AT89C51RC-24AI

Features • • • • • • • • • • • • • • • • • Compatible with MCS®-51 Products 32K Bytes of Reprogrammable Flash Memory Endurance: 1000 Write/Erase Cycles 4V to 5.5V Operating Range Fully Static Operation: 0 Hz to 33 MHz Three-level Program Memory Lock 512 x 8-bit Internal RAM 32 Programmable I/O Lines Three 16-bit Timer/Counters Eight Interrupt Sources Programmable Serial Channel Low-power Idle and Power-down Modes Interrupt Recovery from Power-down Mode Hardware Watchdog Timer Dual Data Pointer Power-off Flag Green (Pb/Halide-free) Packaging Option 8-bit Microcontroller with 32K Bytes Flash AT89C51RC 1. Description The AT89C51RC is a low-power, high-performance CMOS 8-bit microcontroller with 32K bytes of Flash programmable read-only memory and 512 bytes of RAM. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 and 80C52 instruction set and pinout. The on-chip Flash allows the program memory to be user programmed by a conventional nonvolatile memory programmer. A total of 512 bytes of internal RAM are available in the AT89C51RC. The 256-byte expanded internal RAM is accessed via MOVX instructions after clearing bit 1 in the SFR located at address 8EH. The other 256-byte RAM segment is accessed the same way as the Atmel AT89-series and other 8052-compatible products. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51RC is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications. The AT89C51RC provides the following standard features: 32K bytes of Flash, 512 bytes of RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89C51RC is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next external interrupt or hardware reset. 1920C–MICRO–03/05 2. Pin Configurations 2.1 44A – 44-lead TQFP P1.4 P1.3 P1.2 P1.1 (T2 EX) P1.0 (T2) NC VCC P0.0 (AD0) P0.1 (AD1) P0.2 (AD2) P0.3 (AD3) 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 12 13 14 15 16 17 18 19 20 21 22 P1.5 P1.6 P1.7 RST (RXD) P3.0 NC (TXD) P3.1 (INT0) P3.2 (INT1) P3.3 (T0) P3.4 (T1) P3.5 1 2 3 4 5 6 7 8 9 10 11 P0.4 (AD4) P0.5 (AD5) P0.6 (AD6) P0.7 (AD7) EA/VPP NC ALE/PROG PSEN P2.7 (A15) P2.6 (A14) P2.5 (A13) 2.2 44J – 44-lead PLCC P1.4 P1.3 P1.2 P1.1 (T2 EX) P1.0 (T2) NC VCC P0.0 (AD0) P0.1 (AD1) P0.2 (AD2) P0.3 (AD3) 2.3 40P6 – 40-lead PDIP (T2) P1.0 (T2EX) P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 RST (RXD) P3.0 (TXD) P3.1 (INT0) P3.2 (INT1) P3.3 (T0) P3.4 (T1) P3.5 (WR) P3.6 (RD) P3.7 XTAL2 XTAL1 GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 VCC P0.0 (AD0) P0.1 (AD1) P0.2 (AD2) P0.3 (AD3) P0.4 (AD4) P0.5 (AD5) P0.6 (AD6) P0.7 (AD7) EA/VPP ALE/PROG PSEN P2.7 (A15) P2.6 (A14) P2.5 (A13) P2.4 (A12) P2.3 (A11) P2.2 (A10) P2.1 (A9) P2.0 (A8) 2 AT89C51RC 1920C–MICRO–03/05 (WR) P3.6 (RD) P3.7 XTAL2 XTAL1 GND NC (A8) P2.0 (A9) P2.1 (A10) P2.2 (A11) P2.3 (A12) P2.4 18 19 20 21 22 23 24 25 26 27 28 P1.5 P1.6 P1.7 RST (RXD) P3.0 NC (TXD) P3.1 (INT0) P3.2 (INT1) P3.3 (T0) P3.4 (T1) P3.5 7 8 9 10 11 12 13 14 15 16 17 6 5 4 3 2 1 44 43 42 41 40 (WR) P3.6 (RD) P3.7 XTAL2 XTAL1 GND GND (A8) P2.0 (A9) P2.1 (A10) P2.2 (A11) P2.3 (A12) P2.4 39 38 37 36 35 34 33 32 31 30 29 P0.4 (AD4) P0.5 (AD5) P0.6 (AD6) P0.7 (AD7) EA/VPP NC ALE/PROG PSEN P2.7 (A15) P2.6 (A14) P2.5 (A13) AT89C51RC 3. Block Diagram P0.0 - P0.7 P2.0 - P2.7 VCC PORT 0 DRIVERS GND PORT 2 DRIVERS RAM ADDR. REGISTER RAM PORT 0 LATCH PORT 2 LATCH FLASH B REGISTER ACC STACK POINTER PROGRAM ADDRESS REGISTER TMP2 TMP1 BUFFER ALU INTERRUPT, SERIAL PORT, AND TIMER BLOCKS PC INCREMENTER PSW PROGRAM COUNTER PSEN ALE/PROG EA / VPP RST PORT 1 LATCH PORT 3 LATCH TIMING AND CONTROL INSTRUCTION REGISTER DUAL DPTR WATCH DOG OSC PORT 1 DRIVERS PORT 3 DRIVERS P1.0 - P1.7 P3.0 - P3.7 3 1920C–MICRO–03/05 4. Pin Description 4.1 VCC Supply voltage. 4.2 GND Ground. 4.3 Port 0 Port 0 is an 8-bit open drain bi-directional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance inputs. Port 0 can also be configured to be the multiplexed low-order address/data bus during accesses to external program and data memory. In this mode, P0 has internal pull-ups. Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External pull-ups are required during program verification. 4.4 Port 1 Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups. In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively, as shown in the following table. Port 1 also receives the low-order address bytes during Flash programming and verification. Port Pin P1.0 P1.1 Alternate Functions T2 (external count input to Timer/Counter 2), clock-out T2EX (Timer/Counter 2 capture/reload trigger and direction control) 4.5 Port 2 Port 2 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pull-ups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register. Port 2 also receives the high-order address bits and some control signals during Flash programming and verification. 4 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 4.6 Port 3 Port 3 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pull-ups. Port 3 receives some control signals for Flash programming and verification. Port 3 also serves the functions of various special features of the AT89C51RC, as shown in the following table. Port Pin P3.0 P3.1 P3.2 P3.3 P3.4 P3.5 P3.6 P3.7 Alternate Functions RXD (serial input port) TXD (serial output port) INT0 (external interrupt 0) INT1 (external interrupt 1) T0 (timer 0 external input) T1 (timer 1 external input) WR (external data memory write strobe) RD (external data memory read strobe) 4.7 RST Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device. This pin drives High for 98 oscillator periods after the Watchdog times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state of bit DISRTO, the RESET HIGH out feature is enabled. 4.8 ALE/PROG Address Latch Enable is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode. 4.9 PSEN Program Store Enable is the read strobe to external program memory. When the AT89C51RC is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory. 5 1920C–MICRO–03/05 4.10 EA/VPP External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming. 4.11 XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. 4.12 XTAL2 Output from the inverting oscillator amplifier. 5. Special Function Registers A map of the on-chip memory area called the Special Function Register (SFR) space is shown in Table 5-1. Table 5-1. 0F8H 0F0H 0E8H 0E0H 0D8H 0D0H 0C8H 0C0H 0B8H 0B0H 0A8H 0A0H 98H 90H 88H 80H IP XX000000 P3 11111111 IE 0X000000 P2 11111111 SCON 00000000 P1 11111111 TCON 00000000 P0 11111111 TMOD 00000000 SP 00000111 TL0 00000000 DP0L 00000000 TL1 00000000 DP0H 00000000 TH0 00000000 DP1L 00000000 TH1 00000000 DP1H 00000000 AUXR XXX00X00 PCON 0XXX0000 SBUF XXXXXXXX AUXR1 XXXXXXX0 WDTRST XXXXXXXX PSW 00000000 T2CON 00000000 T2MOD XXXXXX00 RCAP2L 00000000 RCAP2H 00000000 TL2 00000000 TH2 00000000 ACC 00000000 B 00000000 AT89C51RC SFR Map and Reset Values 0FFH 0F7H 0EFH 0E7H 0DFH 0D7H 0CFH 0C7H 0BFH 0B7H 0AFH 0A7H 9FH 97H 8FH 87H 6 AT89C51RC 1920C–MICRO–03/05 AT89C51RC Note that not all of the addresses are occupied, and unoccupied addresses may not be implemented on the chip. Read accesses to these addresses will in general return random data, and write accesses will have an indeterminate effect. User software should not write 1s to these unlisted locations, since they may be used in future products to invoke new features. In that case, the reset or inactive values of the new bits will always be 0. Timer 2 Registers: Control and status bits are contained in registers T2CON (shown in Table 52) and T2MOD (shown in Table 13-1 and Table 5-4) for Timer 2. The register pair (RCAP2H, RCAP2L) are the Capture/Reload registers for Timer 2 in 16-bit capture mode or 16-bit autoreload mode. Interrupt Registers: The individual interrupt enable bits are in the IE register. Two priorities can be set for each of the six interrupt sources in the IP register. Dual Data Pointer Registers: To facilitate accessing both internal and external data memory, two banks of 16-bit Data Pointer Registers are provided: DP0 at SFR address locations 82H83H and DP1 at 84H-85H. Bit DPS = 0 in SFR AUXR1 selects DP0 and DPS = 1 selects DP1. The user should always initialize the DPS bit to the appropriate value before accessing the respective Data Pointer Register. Power Off Flag: The Power Off Flag (POF) is located at bit 4 (PCON.4) in the PCON SFR. POF is set to “1” during power up. It can be set and reset under software control and is not affected by reset. 7 1920C–MICRO–03/05 Table 5-2. T2CON – Timer/Counter 2 Control Register Reset Value = 0000 0000B T2CON Address = 0C8H Bit Addressable TF2 Bit 7 Symbol TF2 Function 6 5 4 3 2 EXF2 RCLK TCLK EXEN2 TR2 C/T2 1 CP/RL2 0 Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2 will not be set when either RCLK = 1 or TCLK = 1. Timer 2 external flag set when either a capture or reload is caused by a negative transition on T2EX and EXEN2 = 1. When Timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2 interrupt routine. EXF2 must be cleared by software. EXF2 does not cause an interrupt in up/down counter mode (DCEN = 1). Receive clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock in serial port Modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock. Transmit clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock in serial port Modes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock. Timer 2 external enable. When set, allows a capture or reload to occur as a result of a negative transition on T2EX if Timer 2 is not being used to clock the serial port. EXEN2 = 0 causes Timer 2 to ignore events at T2EX. Start/Stop control for Timer 2. TR2 = 1 starts the timer. Timer or counter select for Timer 2. C/T2 = 0 for timer function. C/T2 = 1 for external event counter (falling edge triggered). Capture/Reload select. CP/RL2 = 1 causes captures to occur on negative transitions at T2EX if EXEN2 = 1. CP/RL2 = 0 causes automatic reloads to occur when Timer 2 overflows or negative transitions occur at T2EX when EXEN2 = 1. When either RCLK or TCLK = 1, this bit is ignored and the timer is forced to auto-reload on Timer 2 overflow. EXF2 RCLK TCLK EXEN2 TR2 C/T2 CP/RL2 8 AT89C51RC 1920C–MICRO–03/05 AT89C51RC Table 5-3. AUXR AUXR: Auxiliary Register Address = 8EH Not Bit Addressable – Bit 7 – 6 – 5 WDIDLE 4 DISRTO 3 – 2 EXTRAM 1 DISALE 0 Reset Value = XXX00X00B – DISALE Reserved for future expansion Disable/Enable ALE DISALE 0 1 Operating Mode ALE is emitted at a constant rate of 1/6 the oscillator frequency ALE is active only during a MOVX or MOVC instruction EXTRAM Internal/External RAM access using MOVX @ Ri/@DPTR EXTRAM 0 1 Operating Mode Internal ERAM (00H-FFH) access using MOVX @ Ri/@DPTR External data memory access DISRTO Disable/Enable Reset out DISRTO 0 1 Operating Mode Reset pin is driven High after WDT times out Reset pin is input only WDIDLE Disable/Enable WDT in IDLE mode WDIDLE 0 1 Operating Mode WDT continues to count in IDLE mode WDT halts counting in IDLE mode Table 5-4. AUXR1 AUXR1: Auxiliary Register 1 Address = A2H Not Bit Addressable – Bit 7 – 6 – 5 – 4 – 3 – 2 – 1 DPS 0 Reset Value = XXXXXXX0B – DPS Reserved for future expansion Data Pointer Register Select DPS 0 1 Selects DPTR Registers DP0L, DP0H Selects DPTR Registers DP1L, DP1H 9 1920C–MICRO–03/05 6. Memory Organization The MCS-51 devices have a separate address space for Program and Data Memory. Up to 64K bytes each of external Program and Data Memory can be addressed. 7. Program Memory If the EA pin is connected to GND, all program fetches are directed to external memory. On the AT89C51RC, if EA is connected to VCC, program fetches to addresses 0000H through 7FFFH are directed to internal memory and fetches to addresses 8000H through FFFFH are to external memory. 7.1 Data Memory The AT89C51RC has internal data memory that is mapped into four separate segments: the lower 128 bytes of RAM, upper 128 bytes of RAM, 128 bytes special function register (SFR) and 256 bytes expanded RAM (ERAM). The four segments are: 1. The Lower 128 bytes of RAM (addresses 00H to 7FH) are directly and indirectly addressable. 2. The Upper 128 bytes of RAM (addresses 80H to FFH) are indirectly addressable only. 3. The Special Function Registers, SFRs, (addresses 80H to FFH) are directly addressable only. 4. The 256-byte expanded RAM (ERAM, 00H-FFH) is indirectly accessed by MOVX instructions, and with the EXTRAM bit cleared. The Lower 128 bytes can be accessed by either direct or indirect addressing. The Upper 128 bytes can be accessed by indirect addressing only. The Upper 128 bytes occupy the same address space as the SFR. This means they have the same address, but are physically separate from the SFR space. When an instruction accesses an internal location above address 7FH, the CPU knows whether the access is to the upper 128 bytes of data RAM or to SFR space by the addressing mode used in the instruction. Instructions that use direct addressing access SFR space. For example: MOV 0A0H, # data accesses the SFR at location 0S0H (which is P2). Instructions that use indirect addressing access the Upper 128 bytes of data RAM. For example: MOV@R0, # data where R0 contains 0A0H, accesses the data byte at address 0A0H, rather than P2 (whose address is 0A0H). Note that stack operations are examples of indirect addressing, so the upper 128 bytes of data RAM are available as stack space. The 256 bytes of ERAM can be accessed by indirect addressing, with EXTRAM bit cleared and MOVX instructions. This part of memory is physically located on-chip, logically occupying the first 256 bytes of external data memory. 10 AT89C51RC 1920C–MICRO–03/05 AT89C51RC With EXTRAM = 0, the ERAM is indirectly addressed, using the MOVX instruction in combination with any of the registers R0, R1 of the selected bank or DPTR. An access to ERAM will not affect ports P0, P2, P3.6 (WR), and P3.7 (RD). For example, with EXTRAM = 0, MOVX@R0, # data where R0 contains 0A0H, accesses the ERAM at address 0A0H rather than external memory. An access to external data memory locations higher than FFH (i.e. 0100H to FFFFH) will be performed with the MOVX DPTR instructions in the same way as in the standard 80C51, i.e., with P0 and P2 as data/address bus, and P3.6 and P3.7 as write and read timing signals (see Figure 7-1). Figure 7-1. Internal and External Data Memory Address (with EXTRAM = 0) FF FF UPPER 128 BYTES INTERNAL RAM ERAM 256 BYTES 80 LOWER 128 BYTES INTERNAL RAM 00 00 80 FF SPECIAL FUNCTION REGISTER FFFF EXTERNAL DATA MEMORY 0100 0000 With EXTRAM = 1, MOVX @ Ri and MOVX@DPTR will be similar to the standard 80C51. MOVX@Ri will provide an 8-bit address multiplexed with data on Port 0 and any output port pins can be used to output higher-order address bits. This is to provide the external paging capability. MOVX@DPTR will generate a 16-bit address. Port 2 outputs the high-order 8 address bits (the contents of DP0H), while Port 0 multiplexes the low-order 8 address bits (the contents of DP0L) with data. MOVX@Ri and MOVX@DPTR will generate either read or write signals on P3.6 (WR) and P3.7 (RD). The stack pointer (SP) may be located anywhere in the 256 bytes RAM (lower and upper RAM) internal data memory. The stack may not be located in the ERAM. 8. Hardware Watchdog Timer (One-time Enabled with Reset-out) The WDT is intended as a recovery method in situations where the CPU may be subjected to software upsets. The WDT consists of a 13-bit counter and the WatchDog Timer Reset (WDTRST) SFR. The WDT is defaulted to disable from exiting reset. To enable the WDT, a user must write 01EH and 0E1H in sequence to the WDTRST register (SFR location 0A6H). When the WDT is enabled, it will increment every machine cycle while the oscillator is running. The WDT timeout period is dependent on the external clock frequency. There is no way to disable the WDT except through reset (either hardware reset or WDT overflow reset). When WDT overflows, it will drive an output RESET HIGH pulse at the RST pin. 11 1920C–MICRO–03/05 9. Using the WDT To enable the WDT, a user must write 01EH and 0E1H in sequence to the WDTRST register (SFR location 0A6H). When the WDT is enabled, the user needs to service it by writing 01EH and 0E1H to WDTRST to avoid a WDT overflow. The 13-bit counter overflows when it reaches 8191 (1FFFH), and this will reset the device. When the WDT is enabled, it will increment every machine cycle while the oscillator is running. This means the user must re-initialize the WDT at least every 8191 machine cycles. To re-initialize the WDT the user must write 01EH and 0E1H to WDTRST. WDTRST is a write-only register. The WDT counter cannot be read or written. When WDT overflows, it will generate an output RESET pulse at the RST pin. The RESET pulse duration is 98xTOSC, where TOSC=1/FOSC. To make the best use of the WDT, it should be serviced in those sections of code that will periodically be executed within the time required to prevent a WDT reset. 10. WDT During Power-down and Idle In Power-down mode the oscillator stops, which means the WDT also stops. While in Powerdown mode, the user does not need to service the WDT. There are two methods of exiting Power-down mode: by a hardware reset or via a level-activated external interrupt which is enabled prior to entering Power-down mode. When Power-down is exited with hardware reset, servicing the WDT should occur as it normally does whenever the AT89C51RC is reset. Exiting Power-down with an interrupt is significantly different. The interrupt is held low long enough for the oscillator to stabilize. When the interrupt is brought high, the interrupt is serviced. To prevent the WDT from resetting the device while the interrupt pin is held low, the WDT is not started until the interrupt is pulled high. It is suggested that the WDT be reset during the interrupt service for the interrupt used to exit Power-down mode. To ensure that the WDT does not overflow within a few states of exiting Power-down, it is best to reset the WDT just before entering Power-down mode. Before going into the IDLE mode, the WDIDLE bit in SFR AUXR is used to determine whether the WDT continues to count if enabled. The WDT keeps counting during IDLE (WDIDLE bit = 0) as the default state. To prevent the WDT from resetting the AT89C51RC while in IDLE mode, the user should always set up a timer that will periodically exit IDLE, service the WDT, and reenter IDLE mode. With WDIDLE bit enabled, the WDT will stop to count in IDLE mode and resumes the count upon exit from IDLE. 11. UART The UART in the AT89C51RC operates the same way as the UART in the AT89C51 and AT89C52. For more detailed information on the UART operation, please click on the document link below: http://www.atmel.com/dyn/resources/prod_documents/DOC4316.PDF 12 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 12. Timer 0 and 1 Timer 0 and Timer 1 in the AT89C51RC operate the same way as Timer 0 and Timer 1 in the AT89C51 and AT89C52. For further information on the timers’ operation, please click on the document link below: http://www.atmel.com/dyn/resources/prod_documents/DOC4316.PDF 13. Timer 2 Timer 2 is a 16-bit Timer/Counter that can operate as either a timer or an event counter. The type of operation is selected by bit C/T2 in the SFR T2CON (shown in Table 5-2). Timer 2 has three operating modes: capture, auto-reload (up or down counting), and baud rate generator. The modes are selected by bits in T2CON, as shown in Table 13-1. Timer 2 consists of two 8-bit registers, TH2 and TL2. In the Timer function, the TL2 register is incremented every machine cycle. Since a machine cycle consists of 12 oscillator periods, the count rate is 1/12 of the oscillator frequency. Table 13-1. Timer 2 Operating Modes CP/RL2 0 1 X X TR2 1 1 1 0 MODE 16-bit Auto-reload 16-bit Capture Baud Rate Generator (Off) RCLK +TCLK 0 0 1 X In the Counter function, the register is incremented in response to a 1-to-0 transition at its corresponding external input pin, T2. In this function, the external input is sampled during S5P2 of every machine cycle. When the samples show a high in one cycle and a low in the next cycle, the count is incremented. The new count value appears in the register during S3P1 of the cycle following the one in which the transition was detected. Since two machine cycles (24 oscillator periods) are required to recognize a 1-to-0 transition, the maximum count rate is 1/24 of the oscillator frequency. To ensure that a given level is sampled at least once before it changes, the level should be held for at least one full machine cycle. 13.1 Capture Mode In the capture mode, two options are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 is a 16-bit timer or counter which upon overflow sets bit TF2 in T2CON. This bit can then be used to generate an interrupt. If EXEN2 = 1, Timer 2 performs the same operation, but a 1-to-0 transition at external input T2EX also causes the current value in TH2 and TL2 to be captured into RCAP2H and RCAP2L, respectively. In addition, the transition at T2EX causes bit EXF2 in T2CON to be set. The EXF2 bit, like TF2, can generate an interrupt. The capture mode is illustrated in Figure 13-1. 13 1920C–MICRO–03/05 13.2 Auto-Reload (Up or Down Counter) Timer 2 can be programmed to count up or down when configured in its 16-bit auto-reload mode. This feature is invoked by the DCEN (Down Counter Enable) bit located in the SFR T2MOD (see Table 13-2). Upon reset, the DCEN bit is set to 0 so that timer 2 will default to count up. When DCEN is set, Timer 2 can count up or down, depending on the value of the T2EX pin. Figure 13-2 shows Timer 2 automatically counting up when DCEN=0. In this mode, two options are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 counts up to 0FFFFH and then sets the TF2 bit upon overflow. The overflow also causes the timer registers to be reloaded with the 16-bit value in RCAP2H and RCAP2L. The values in Timer in Capture Mode RCAP2H and RCAP2L are preset by software. If EXEN2 = 1, a 16-bit reload can be triggered either by an overflow or by a 1-to-0 transition at external input T2EX. This transition also sets the EXF2 bit. Both the TF2 and EXF2 bits can generate an interrupt if enabled. Setting the DCEN bit enables Timer 2 to count up or down, as shown in Figure 13-2. In this mode, the T2EX pin controls the direction of the count. A logic 1 at T2EX makes Timer 2 count up. The timer will overflow at 0FFFFH and set the TF2 bit. This overflow also causes the 16-bit value in RCAP2H and RCAP2L to be reloaded into the timer registers, TH2 and TL2, respectively. A logic 0 at T2EX makes Timer 2 count down. The timer underflows when TH2 and TL2 equal the values stored in RCAP2H and RCAP2L. The underflow sets the TF2 bit and causes 0FFFFH to be reloaded into the timer registers. The EXF2 bit toggles whenever Timer 2 overflows or underflows and can be used as a 17th bit of resolution. In this operating mode, EXF2 does not flag an interrupt. Figure 13-1. Timer in Capture Mode OSC ÷12 C/T2 = 0 TH2 CONTROL C/T2 = 1 T2 PIN TRANSITION DETECTOR T2EX PIN CONTROL EXEN2 EXF2 TR2 CAPTURE RCAP2H RCAP2L TIMER 2 INTERRUPT TL2 TF2 OVERFLOW 14 AT89C51RC 1920C–MICRO–03/05 AT89C51RC Figure 13-2. Timer 2 Auto Reload Mode (DCEN = 0) OSC 12 C/T2 = 0 TH2 CONTR OL TR2 C/T2 = 1 T2 PIN RCAP2H RCAP2L TF2 TRANSITION DETECTOR T2EX PIN CONTROL EXEN2 EXF2 RELO AD TIMER 2 INTERRUPT TL2 OVERFLOW Table 13-2. T2MOD—Timer 2 Mode Control Register Reset Value = XXXX XX00B T2MOD Address = 0C9H Not Bit Addressable – Bit Symbol – T2OE DCEN 7 Function Not implemented, reserved for future Timer 2 Output Enable bit When set, this bit allows Timer 2 to be configured as an up/down counter – 6 – 5 – 4 – 3 – 2 T2OE 1 DCEN 0 Figure 13-3. Timer 2 Auto Reload Mode (DCEN = 1) (DOWN COUNTING RELOAD VALUE) 0FFH 0FFH TOGGLE EXF2 OSC 12 C/T2 = 0 TH2 CONTROL TR2 C/T2 = 1 T2 PIN TL2 OVERFLOW TF2 TIMER 2 INTERRUPT RCAP2H RCAP2L (UP COUNTING RELOAD VALUE) COUNT DIRECTION 1=UP 0=DO T2EX PIN 15 1920C–MICRO–03/05 14. Baud Rate Generator Timer 2 is selected as the baud rate generator by setting TCLK and/or RCLK in T2CON (Table 5-2). Note that the baud rates for transmit and receive can be different if Timer 2 is used for the receiver or transmitter and Timer 1 is used for the other function. Setting RCLK and/or TCLK puts Timer 2 into its baud rate generator mode, as shown in Figure 14-1. The baud rate generator mode is similar to the auto-reload mode, in that a rollover in TH2 causes the Timer 2 registers to be reloaded with the 16-bit value in registers RCAP2H and RCAP2L, which are preset by software. The baud rates in Modes 1 and 3 are determined by Timer 2’s overflow rate according to the following equation. Timer 2 Overflow Rate Mdes 1 and 3 Baud Rates = ----------------------------------------------------------16 Figure 14-1. Timer 2 in Baud Rate Generator Mode TIMER 1 OVERFLOW ÷2 "0" NOTE: OSC. FREQ. IS DIVIDED BY 2, NOT 12 SMOD1 OSC "1" ÷2 C/T2 = 0 "1" TH2 CONTROL TR2 C/T2 = 1 "1" "0" TCLK Tx CLOCK TL2 RCLK "0" Rx CLOCK ÷ 16 T2 PIN RCAP2H RCAP2L TRANSITION DETECTOR T2EX PIN CONTROL EXEN2 EXF2 TIMER 2 INTERRUPT ÷ 16 The Timer can be configured for either timer or counter operation. In most applications, it is configured for timer operation (CP/T2 = 0). The timer operation is different for Timer 2 when it is used as a baud rate generator. Normally, as a timer, it increments every machine cycle (at 1/12 the oscillator frequency). As a baud rate generator, however, it increments every state time (at 1/2 the oscillator frequency). The baud rate formula is given below. Modes 1 and 3 Oscillator Frequency -------------------------------------- = ------------------------------------------------------------------------------------Baud Rate 32 x [65536-RCAP2H,RCAP2L)] where (RCAP2H, RCAP2L) is the content of RCAP2H and RCAP2L taken as a 16-bit unsigned integer. Timer 2 as a baud rate generator is shown in Figure 14-1. This figure is valid only if RCLK or TCLK = 1 in T2CON. Note that a rollover in TH2 does not set TF2 and will not generate an inter- 16 AT89C51RC 1920C–MICRO–03/05 AT89C51RC rupt. Note too, that if EXEN2 is set, a 1-to-0 transition in T2EX will set EXF2 but will not cause a reload from (RCAP2H, RCAP2L) to (TH2, TL2). Thus when Timer 2 is in use as a baud rate generator, T2EX can be used as an extra external interrupt. Note that when Timer 2 is running (TR2 = 1) as a timer in the baud rate generator mode, TH2 or TL2 should not be read from or written to. Under these conditions, the Timer is incremented every state time, and the results of a read or write may not be accurate. The RCAP2 registers may be read but should not be written to, because a write might overlap a reload and cause write and/or reload errors. The timer should be turned off (clear TR2) before accessing the Timer 2 or RCAP2 registers. 15. Programmable Clock Out A 50% duty cycle clock can be programmed to come out on P1.0, as shown in Figure 15-1. This pin, besides being a regular I/O pin, has two alternate functions. It can be programmed to input the external clock for Timer/Counter 2 or to output a 50% duty cycle clock ranging from 61 Hz to 4 MHz at a 16 MHz operating frequency. To configure the Timer/Counter 2 as a clock generator, bit C/T2 (T2CON.1) must be cleared and bit T2OE (T2MOD.1) must be set. Bit TR2 (T2CON.2) starts and stops the timer. The clock-out frequency depends on the oscillator frequency and the reload value of Timer 2 capture registers (RCAP2H, RCAP2L), as shown in the following equation. Oscillator Frequency Clock-Out Frequency = -----------------------------------------------------------------------------------4 x [65536-(RCAP2H,RCAP2L)] In the clock-out mode, Timer 2 roll-overs will not generate an interrupt. This behavior is similar to when Timer 2 is used as a baud-rate generator. It is possible to use Timer 2 as a baud-rate generator and a clock generator simultaneously. Note, however, that the baud-rate and clock-out frequencies cannot be determined independently from one another since they both use RCAP2H and RCAP2L. Figure 15-1. Timer 2 in Clock-Out Mode OSC ÷2 TL2 (8-BITS) TH2 (8-BITS) TR2 RCAP2L RCAP2H C/T2 BIT P1.0 (T2) ÷2 T2OE (T2MOD.1) TRANSITION DETECTOR P1.1 (T2EX) TIMER 2 INTERRUPT EXF2 EXEN2 17 1920C–MICRO–03/05 16. Interrupts The AT89C51RC has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. These interrupts are all shown in Figure 16-1. Each of these interrupt sources can be individually enabled or disabled by setting or clearing a bit in Special Function Register IE. IE also contains a global disable bit, EA, which disables all interrupts at once. Note that Table 14-1 shows that bit position IE.6 is unimplemented. User software should not write 1s to these bit positions, since they may be used in future AT89 products. Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in register T2CON. Neither of these flags is cleared by hardware when the service routine is vectored to. In fact, the service routine may have to determine whether it was TF2 or EXF2 that generated the interrupt, and that bit will have to be cleared in software. The Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 of the cycle in which the timers overflow. The values are then polled by the circuitry in the next cycle. However, the Timer 2 flag, TF2, is set at S2P2 and is polled in the same cycle in which the timer overflows. Table 16-1. (MSB) EA – ET2 ES ET1 Interrupt Enable (IE) Register (LSB) EX1 ET0 EX0 Enable Bit = 1 enables the interrupt. Enable Bit = 0 disables the interrupt. Symbol Position Function Disables all interrupts. If EA = 0, no interrupt is acknowledged. If EA = 1, each interrupt source is individually enabled or disabled by setting or clearing its enable bit. Reserved. Timer 2 interrupt enable bit. Serial Port interrupt enable bit. Timer 1 interrupt enable bit. External interrupt 1 enable bit. Timer 0 interrupt enable bit. External interrupt 0 enable bit. EA IE.7 – ET2 ES ET1 EX1 ET0 EX0 IE.6 IE.5 IE.4 IE.3 IE.2 IE.1 IE.0 User software should never write 1s to reserved bits, because they may be used in future AT89 products. 18 AT89C51RC 1920C–MICRO–03/05 AT89C51RC Figure 16-1. Interrupt Sources 0 INT0 1 IE0 TF0 0 INT1 1 IE1 TF1 TI RI TF2 EXF2 17. Oscillator Characteristics XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be configured for use as an on-chip oscillator, as shown in Figure 19-1. Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven, as shown in Figure 19-2. There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed. 18. Idle Mode In idle mode, the CPU puts itself to sleep while all the on-chip peripherals remain active. The mode is invoked by software. The content of the on-chip RAM and all the special functions registers remain unchanged during this mode. The idle mode can be terminated by any enabled interrupt or by a hardware reset. Note that when idle mode is terminated by a hardware reset, the device normally resumes program execution from where it left off, up to two machine cycles before the internal reset algorithm takes control. On-chip hardware inhibits access to internal RAM in this event, but access to the port pins is not inhibited. To eliminate the possibility of an unexpected write to a port pin when idle mode is terminated by a reset, the instruction following the one that invokes idle mode should not write to a port pin or to external memory. 19 1920C–MICRO–03/05 19. Power-down Mode In the Power-down mode, the oscillator is stopped, and the instruction that invokes Power-down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values until the Power-down mode is terminated. Exit from Power-down can be initiated either by a hardware reset or by an enabled external interrupt. Reset redefines the SFRs but does not change the on-chip RAM. The reset should not be activated before VCC is restored to its normal operating level and must be held active long enough to allow the oscillator to restart and stabilize. Figure 19-1. Oscillator Connections C2 XTAL2 C1 XTAL1 GND Note: C1, C2 = 30 pF ± 10 pF for Crystals = 40 pF ± 10 pF for Ceramic Resonators Figure 19-2. External Clock Drive Configuration NC XTAL2 EXTERNAL OSCILLATOR SIGNAL XTAL1 GND Table 19-1. Mode Idle Idle Power-down Power-down Status of External Pins During Idle and Power-down Modes Program Memory Internal External Internal External ALE 1 1 0 0 PSEN 1 1 0 0 PORT0 Data Float Data Float PORT1 Data Data Data Data PORT2 Data Address Data Data PORT3 Data Data Data Data 20 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 20. Program Memory Lock Bits The AT89C51RC has three lock bits that can be left unprogrammed (U) or can be programmed (P) to obtain the additional features listed in Table 20-1. Table 20-1. Lock Bit Protection Modes Program Lock Bits LB1 1 U LB2 U LB3 U Protection Type No program lock features MOVC instructions executed from external program memory are disabled from fetching code bytes from internal memory, EA is sampled and latched on reset, and further programming of the Flash memory is disabled Same as mode 2, but verify is also disabled Same as mode 3, but external execution is also disabled 2 P U U 3 4 P P P P U P When lock bit 1 is programmed, the logic level at the EA pin is sampled and latched during reset. If the device is powered up without a reset, the latch initializes to a random value and holds that value until reset is activated. The latched value of EA must agree with the current logic level at that pin in order for the device to function properly. 21. Programming the Flash The AT89C51RC is shipped with the on-chip Flash memory array ready to be programmed. The programming interface needs a high-voltage (12-volt) program enable signal and is compatible with conventional third-party Flash or EPROM programmers. The AT89C51RC code memory array is programmed byte-by-byte. Programming Algorithm: Before programming the AT89C51RC, the address, data, and control signals should be set up according to Table 22-1 and Figures 22-1 and 22-2. To program the AT89C51RC, take the following steps: 1. Input the desired memory location on the address lines. 2. Input the appropriate data byte on the data lines. 3. Activate the correct combination of control signals. 4. Raise EA/VPP to 12V. 5. Pulse ALE/PROG once to program a byte in the Flash array or the lock bits. The bytewrite cycle is self-timed and typically takes no more than 50 µs. Repeat steps 1 through 5, changing the address and data for the entire array or until the end of the object file is reached. 21 1920C–MICRO–03/05 Chip Erase Sequence: Before the AT89C51RC can be reprogrammed, a Chip Erase operation needs to be performed. To erase the contents of the AT89C51RC, follow this sequence: 1. Raise VCC to 6.5V. 2. Pulse ALE/PROG once (duration of 200 ns - 500 ns) and wait for 150 ms. 3. Power VCC down and up to 6.5V. 4. Pulse ALE/PROG once (duration of 200 ns - 500 ns) and wait for 150 ms. 5. Power VCC down and up. Data Polling: The AT89C51RC features Data Polling to indicate the end of a write cycle. During a write cycle, an attempted read of the last byte written will result in the complement of the written data on P0.7. Once the write cycle has been completed, true data is valid on all outputs, and the next cycle may begin. Data Polling may begin any time after a write cycle has been initiated. Ready/Busy: The progress of byte programming can also be monitored by the RDY/BSY output signal. P3.0 is pulled low after ALE goes high during programming to indicate BUSY. P3.0 is pulled high again when programming is done to indicate READY. Program Verify: If lock bits LB1 and LB2 have not been programmed, the programmed code data can be read back via the address and data lines for verification. The status of the individual lock bits can be verified directly by reading them back. Reading the Signature Bytes: The signature bytes are read by the same procedure as a normal verification of locations 000H, 100H, and 200H, except that P3.6 and P3.7 must be pulled to a logic low. The values returned are as follows: (000H) = 1EH indicates manufactured by Atmel (100H) = 51H (200H) = 07H indicates 89C51RC 22 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 22. Programming Interface Every code byte in the Flash array can be programmed by using the appropriate combination of control signals. The write operation cycle is self-timed and once initiated, will automatically time itself to completion. Most major worldwide programming vendors offer support for the Atmel AT89 microcontroller series. Please contact your local programming vendor for the appropriate software revision. Table 22-1. Flash Programming Modes ALE/ Mode Write Code Data Read Code Data Write Lock Bit 1 Write Lock Bit 2 Write Lock Bit 3 Read Lock Bits 1, 2, 3 Chip Erase Read Atmel ID Read Device ID Read Device ID VCC 5V 5V 6.5V 6.5V 6.5V RST H H H H H PSEN L L L (2) EA/ VPP 12 V P2.6 L L H H H P2.7 H L H H L P3.3 H L H H H P3.6 H H H L H P3.7 H H H L L P0.7-0 Data DIN DOUT X X X P0.2, P0.3, P0.4 X 1EH 51H 07H P3.4 P2.5-0 Address P1.7-0 PROG (1) A14 A14 X X X A13-8 A13-8 X X X A7-0 A7-0 X X X H (2) H/12 V 12 V 12 V L (2) L 12 V 5V H L H (3) H H H L H L X X X 6.5V 5V 5V 5V H H H H L L L L H H H 12V H H H H L L L L L L L H L L L L L L L L L L L X X X X X XX 0000 XX 0001 XX 0010 X 00H 00H 00H Notes: 1. 2. 3. 4. Write Code Data requires a 200 ns PROG pulse. Write Lock Bits requires a 100 µs PROG pulse. Chip Erase requires a 200 ns - 500 ns PROG pulse. RDY/BSY signal is output on P3.0 during programming. 23 1920C–MICRO–03/05 Figure 22-1. Programming the Flash Memory 4.5V to 5.5V AT89C51RC ADDR. 0000H/7FFFH A0 - A7 A8 - A13 P1.0 - P1.7 P2.0 - P2.5 P3.4 P2.6 P2.7 P3.3 P3.6 P3.7 XTAL2 EA VIH/VPP VCC P0 PGM DATA A14* SEE FLASH PROGRAMMING MODES TABLE ALE PROG 3 - 33 MHz P3.0 RDY/ BSY XTAL1 GND RST PSEN VIH Figure 22-2. Verifying the Flash Memory 4.5V to 5.5V AT89C51RC ADDR. 0000H/7FFFH A0 - A7 A8 - A13 A14* SEE FLASH PROGRAMMING MODES TABLE P2.0 - P2.5 P3.4 P2.6 P2.7 P3.3 P3.6 P3.7 XTAL 2 P1.0 - P1.7 VCC P0 PGM DATA (USE 10K PULL-UPS) ALE VIH EA 3 - 33 MHz XTAL1 GND RST PSEN VIH Note: *Programming address line A14 (P3.4) is not the same as the external memory address line A14 (P2.6). 24 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 23. Flash Programming and Verification Characteristics TA = 20°C to 30°C, VCC = 4.5V to 5.5V Symbol VPP IPP ICC 1/tCLCL tAVGL tGHAX tDVGL tGHDX tEHSH tSHGL tGHSL tGLGH tAVQV tELQV tEHQZ tGHBL tWC Parameter Programming Supply Voltage Programming Supply Current VCC Supply Current Oscillator Frequency Address Setup to PROG Low Address Hold after PROG Data Setup to PROG Low Data Hold after PROG P2.7 (ENABLE) High to VPP VPP Setup to PROG Low VPP Hold after PROG PROG Width Address to Data Valid ENABLE Low to Data Valid Data Float after ENABLE PROG High to BUSY Low Byte Write Cycle Time 0 3 48tCLCL 48tCLCL 48tCLCL 48tCLCL 48tCLCL 10 10 0.2 1 48tCLCL 48tCLCL 48tCLCL 1.0 80 µs µs µs µs µs Min 11.5 Max 12.5 10 30 33 Units V mA mA MHz 25 1920C–MICRO–03/05 24. Flash Programming and Verification Waveforms P1.0 - P1.7 P2.0 - P2.5 P3.4 PORT 0 PROGRAMMING ADDRESS VERIFICATION ADDRESS tAVQV DATA IN DATA OUT tAVGL ALE/PROG tDVGL tGHDX tGHAX tGHSL LOGIC 1 LOGIC 0 tSHGL VPP tGLGH EA/VPP tEHSH P2.7 (ENABLE) tELQV tGHBL tEHQZ P3.0 (RDY/BSY) BUSY READY tWC 25. Lock Bit Programming Test Conditions Setup Lockbit_1, 2 or 3 Data Setup 100 µs ALE/PROG VCC = 6.5V VCC = 4.5V to 5.5V Wait 10 ms to reload new lock bit status 26. Parallel Chip Erase Mode Test Conditions Setup Test Conditions Setup 200 ns ALE/PROG 200 ns P3 VCC = 6.5V Erase DC Erase Erase DC Erase VCC = 4.5V to 5.5V Wait 10 ms before reprogramming 10 ms 26 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 27. Absolute Maximum Ratings* Operating Temperature.................................. -55°C to +125°C Storage Temperature ..................................... -65°C to +150°C Voltage on Any Pin with Respect to Ground .....................................-1.0V to +7.0V Maximum Operating Voltage ............................................ 6.6V DC Output Current...................................................... 15.0 mA *NOTICE: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. 28. DC Characteristics The values shown in this table are valid for TA = -40°C to 85°C and VCC = 4.0V to 5.5V, unless otherwise noted. Symbol VIL VIL1 VIH VIH1 VOL VOL1 Parameter Input Low-voltage Input Low-voltage (EA) Input High-voltage Input High-voltage Output Low-voltage(1) (Ports 1,2,3) Output Low-voltage(1) (Port 0, ALE, PSEN) Output High-voltage (Ports 1,2,3, ALE, PSEN) (Except XTAL1, RST) (XTAL1, RST) IOL = 1.6 mA IOL = 3.2 mA IOH = -60 µA, VCC = 5V ± 10% VOH IOH = -25 µA IOH = -10 µA IOH = -800 µA, VCC = 5V ± 10% VOH1 Output High-voltage (Port 0 in External Bus Mode) Logical 0 Input Current (Ports 1,2,3) Logical 1 to 0 Transition Current (Ports 1,2,3) Input Leakage Current (Port 0, EA) Reset Pull-down Resistor Pin Capacitance Power Supply Current ICC Power-down Mode(1) Notes: Idle Mode, 12 MHz VCC = 5.5V 6.5 100 mA µA Test Freq. = 1 MHz, TA = 25°C Active Mode, 12 MHz IOH = -300 µA IOH = -80 µA IIL ITL ILI RRST CIO VIN = 0.45V VIN = 2V, VCC = 5V ± 10% 0.45 < VIN < VCC 10 2.4 0.75 VCC 0.9 VCC 2.4 0.75 VCC 0.9 VCC -50 -650 ±10 30 10 25 Condition (Except EA) Min -0.5 -0.5 0.2 VCC+0.9 0.7 VCC Max 0.2 VCC-0.1 0.2 VCC-0.3 VCC+0.5 VCC+0.5 0.45 0.45 Units V V V V V V V V V V V V µA µA µA kΩ pF mA 1. Under steady state (non-transient) conditions, IOL must be externally limited as follows: Maximum IOL per port pin: 10 mA Maximum IOL per 8-bit port: Port 0: 26 mA Ports 1, 2, 3: 15 mA Maximum total IOL for all output pins: 71 mA If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed test conditions. 2. Minimum VCC for Power-down is 2V. 27 1920C–MICRO–03/05 29. AC Characteristics Under operating conditions, load capacitance for Port 0, ALE/PROG, and PSEN = 100 pF; load capacitance for all other outputs = 80 pF. 29.1 External Program and Data Memory Characteristics 12 MHz Oscillator Variable Oscillator Min 0 127 43 48 233 43 205 145 0 59 75 312 10 400 400 252 0 97 517 585 200 203 23 433 33 0 43 123 tCLCL-25 300 3tCLCL-50 4tCLCL-75 tCLCL-30 7tCLCL-130 tCLCL-25 0 tCLCL+25 0 2tCLCL-28 8tCLCL-150 9tCLCL-165 3tCLCL+50 6tCLCL-100 6tCLCL-100 5tCLCL-90 tCLCL-8 5tCLCL-80 10 0 tCLCL-25 tCLCL-25 3tCLCL-45 3tCLCL-60 2tCLCL-40 tCLCL-25 tCLCL-25 4tCLCL-65 Max 33 Units MHz ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns Parameter Oscillator Frequency ALE Pulse Width Address Valid to ALE Low Address Hold after ALE Low ALE Low to Valid Instruction In ALE Low to PSEN Low PSEN Pulse Width PSEN Low to Valid Instruction In Input Instruction Hold after PSEN Input Instruction Float after PSEN PSEN to Address Valid Address to Valid Instruction In PSEN Low to Address Float RD Pulse Width WR Pulse Width RD Low to Valid Data In Data Hold after RD Data Float after RD ALE Low to Valid Data In Address to Valid Data In ALE Low to RD or WR Low Address to RD or WR Low Data Valid to WR Transition Data Valid to WR High Data Hold after WR RD Low to Address Float RD or WR High to ALE High Min Max Symbol 1/tCLCL tLHLL tAVLL tLLAX tLLIV tLLPL tPLPH tPLIV tPXIX tPXIZ tPXAV tAVIV tPLAZ tRLRH tWLWH tRLDV tRHDX tRHDZ tLLDV tAVDV tLLWL tAVWL tQVWX tQVWH tWHQX tRLAZ tWHLH 28 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 30. External Program Memory Read Cycle tLHLL ALE tAVLL PSEN tPLAZ tLLAX PORT 0 A0 - A7 tLLPL tLLIV tPLIV tPLPH tPXAV tPXIZ tPXIX INSTR IN A0 - A7 tAVIV PORT 2 A8 - A15 A8 - A15 31. External Data Memory Read Cycle tLHLL ALE tWHLH PSEN tLLDV tLLWL RD tAVLL PORT 0 tLLAX tRLAZ DATA IN tRLRH tRLDV tRHDZ tRHDX A0 - A7 FROM PCL INSTR IN A0 - A7 FROM RI OR DPL tAVWL tAVDV PORT 2 P2.0 - P2.7 OR A8 - A15 FROM DPH A8 - A15 FROM PCH 29 1920C–MICRO–03/05 32. External Data Memory Write Cycle tLHLL ALE tWHLH PSEN tLLWL WR tAVLL PORT 0 tLLAX tQVWX tWLWH tQVWH DATA OUT tWHQX A0 - A7 FROM PCL INSTR IN A0 - A7 FROM RI OR DPL tAVWL PORT 2 P2.0 - P2.7 OR A8 - A15 FROM DPH A8 - A15 FROM PCH 33. External Clock Drive Waveforms tCHCX VCC - 0.5V 0.7 VCC 0.2 VCC - 0.1V 0.45V tCHCX tCLCH tCHCL tCLCX tCLCL 34. External Clock Drive Symbol 1/tCLCL tCLCL tCHCX tCLCX tCLCH tCHCL Parameter Oscillator Frequency Clock Period High Time Low Time Rise Time Fall Time Min 0 30 12 12 5 5 Max 33 Units MHz ns ns ns ns ns 30 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 35. Serial Port Timing: Shift Register Mode Test Conditions The values in this table are valid for VCC = 4.0V to 5.5V and Load Capacitance = 80 pF. 12 MHz Osc Symbol tXLXL tQVXH tXHQX tXHDX tXHDV Parameter Serial Port Clock Cycle Time Output Data Setup to Clock Rising Edge Output Data Hold after Clock Rising Edge Input Data Hold after Clock Rising Edge Clock Rising Edge to Input Data Valid Min 1.0 700 50 0 700 Max Variable Oscillator Min 12tCLCL 10tCLCL - 133 2tCLCL - 80 0 10tCLCL - 133 Max Units µs ns ns ns ns 36. Shift Register Mode Timing Waveforms INSTRUCTION ALE CLOCK 0 1 2 3 4 5 6 7 8 tXLXL tQVXH WRITE TO SBUF tXHQX 0 1 2 3 4 5 6 7 SET TI VALID VALID VALID VALID VALID OUTPUT DATA CLEAR RI INPUT DATA tXHDV VALID VALID tXHDX VALID SET RI 37. AC Testing Input/Output Waveforms(1) VCC - 0.5V 0.2 VCC + 0.9V TEST POINTS 0.45V 0.2 VCC - 0.1V Note: 1. AC Inputs during testing are driven at VCC - 0.5V for a logic 1 and 0.45V for a logic 0. Timing measurements are made at VIH min. for a logic 1 and VIL max. for a logic 0. 38. Float Waveforms(1) V LOAD+ V LOAD V LOAD Note: 0.1V 0.1V V OL Timing Reference Points V OL + 0.1V 0.1V 1. For timing purposes, a port pin is no longer floating when a 100 mV change from load voltage occurs. A port pin begins to float when a 100 mV change from the loaded VOH/VOL level occurs. 31 1920C–MICRO–03/05 39. Ordering Information 39.1 Standard Package Power Supply Ordering Code AT89C51RC-24AC AT89C51RC-24JC AT89C51RC-24PC AT89C51RC-24AI AT89C51RC-24JI AT89C51RC-24PI AT89C51RC-33AC AT89C51RC-33JC AT89C51RC-33PC Package 44A 44J 40P6 44A 44J 40P6 44A 44J 40P6 Operation Range Commercial (0°C to 70°C) Industrial (-40°C to 85°C) Commercial (0°C to 70°C) Speed (MHz) 24 4.0V to 5.5V 33 4.5V to 5.5V 39.2 Green Package Option (Pb/Halide-free) Power Supply 4.0V to 5.5V Ordering Code AT89C51RC-24AU AT89C51RC-24JU AT89C51RC-24PU Package 44A 44J 40P6 Operation Range Industrial (-40°C to 85°C) Speed (MHz) 24 Package Type 44A 44J 40P6 44-lead, Thin Plastic Gull Wing Quad Flatpack (TQFP) 44-lead, Plastic J-leaded Chip Carrier (PLCC) 40-lead, 0.600" Wide, Plastic Dual Inline Package (PDIP) 32 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 40. Package Information 40.1 44A – TQFP PIN 1 B PIN 1 IDENTIFIER e E1 E D1 D C 0˚~7˚ A1 L COMMON DIMENSIONS (Unit of Measure = mm) SYMBOL A A1 A2 D D1 E MIN – 0.05 0.95 11.75 9.90 11.75 9.90 0.30 0.09 0.45 NOM – – 1.00 12.00 10.00 12.00 10.00 – – – 0.80 TYP MAX 1.20 0.15 1.05 12.25 10.10 12.25 10.10 0.45 0.20 0.75 Note 2 Note 2 NOTE A2 A Notes: 1. This package conforms to JEDEC reference MS-026, Variation ACB. 2. Dimensions D1 and E1 do not include mold protrusion. Allowable protrusion is 0.25 mm per side. Dimensions D1 and E1 are maximum plastic body size dimensions including mold mismatch. 3. Lead coplanarity is 0.10 mm maximum. E1 B C L e 10/5/2001 2325 Orchard Parkway San Jose, CA 95131 TITLE 44A, 44-lead, 10 x 10 mm Body Size, 1.0 mm Body Thickness, 0.8 mm Lead Pitch, Thin Profile Plastic Quad Flat Package (TQFP) DRAWING NO. 44A REV. B R 33 1920C–MICRO–03/05 40.2 44J – PLCC 1.14(0.045) X 45˚ PIN NO. 1 IDENTIFIER 1.14(0.045) X 45˚ 0.318(0.0125) 0.191(0.0075) E1 B E B1 D2/E2 e D1 D A A2 A1 0.51(0.020)MAX 45˚ MAX (3X) COMMON DIMENSIONS (Unit of Measure = mm) SYMBOL A A1 A2 D D1 E Notes: 1. This package conforms to JEDEC reference MS-018, Variation AC. 2. Dimensions D1 and E1 do not include mold protrusion. Allowable protrusion is .010"(0.254 mm) per side. Dimension D1 and E1 include mold mismatch and are measured at the extreme material condition at the upper or lower parting line. 3. Lead coplanarity is 0.004" (0.102 mm) maximum. E1 D2/E2 B B1 e MIN 4.191 2.286 0.508 17.399 16.510 17.399 16.510 14.986 0.660 0.330 NOM – – – – – – – – – – 1.270 TYP MAX 4.572 3.048 – 17.653 16.662 17.653 16.662 16.002 0.813 0.533 Note 2 Note 2 NOTE 10/04/01 2325 Orchard Parkway San Jose, CA 95131 TITLE 44J, 44-lead, Plastic J-leaded Chip Carrier (PLCC) DRAWING NO. 44J REV. B R 34 AT89C51RC 1920C–MICRO–03/05 AT89C51RC 40.3 40P6 – PDIP D PIN 1 E1 A SEATING PLANE L B1 e E B A1 C eB 0º ~ 15º REF SYMBOL A A1 D E E1 B COMMON DIMENSIONS (Unit of Measure = mm) MIN – 0.381 52.070 15.240 13.462 0.356 1.041 3.048 0.203 15.494 NOM – – – – – – – – – – 2.540 TYP MAX 4.826 – 52.578 15.875 13.970 0.559 1.651 3.556 0.381 17.526 Note 2 Note 2 NOTE Notes: 1. This package conforms to JEDEC reference MS-011, Variation AC. 2. Dimensions D and E1 do not include mold Flash or Protrusion. Mold Flash or Protrusion shall not exceed 0.25 mm (0.010"). B1 L C eB e 09/28/01 2325 Orchard Parkway San Jose, CA 95131 TITLE 40P6, 40-lead (0.600"/15.24 mm Wide) Plastic Dual Inline Package (PDIP) DRAWING NO. 40P6 REV. B R 35 1920C–MICRO–03/05 A tmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 1150 East Cheyenne Mtn. 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