SST25WF020AT-40I/SN

SST25WF020A 2 Mbit 1.8V SPI Serial Flash Features • Single Voltage Read and Write Operations - 1.65-1.95V • Serial Interface Architecture - SPI Compatible: Mode 0 and Mode 3 • High Speed Clock Frequency - 40MHz • Superior Reliability - Endurance: 100,000 Cycles - Greater than 20 years Data Retention • Ultra-Low Power Consumption: - Active Read Current: 4 mA (typical) - Standby Current: 10 µA (typical) - Power-down Mode Standby Current: 4 µA (typical) • Flexible Erase Capability - Uniform 4 KByte sectors - Uniform 64 KByte overlay blocks • Page Program Mode - 256 Bytes/Page • Fast Erase and Page-Program: - Chip-Erase Time: 300 ms (typical) - Sector-Erase Time: 40 ms (typical) - Block-Erase Time: 80 ms (typical) - Page-Program Time: 3 ms/ 256 bytes (typical) • End-of-Write Detection - Software polling the BUSY bit in Status Register • Hold Pin (HOLD#) - Suspend a serial sequence without deselecting the device • Write-Protection (WP#) - Enables/Disables the Lock-Down function of the status register • Software Write-Protection - Write protection through Block-Protection bits in status register • Temperature Range - Industrial: -40°C to +85°C  2014-2017 Microchip Technology Inc. • Packages Available - 8-lead SOIC (150 mils) - 8-contact USON (2mm x 3mm) - 8-contact WDFN(5mm x 6mm) • All devices are RoHS compliant Product Description SST25WF020A is a member of the Serial Flash 25 Series family and feature a four-wire, SPI-compatible interface that allows for a low pin count package which occupies less board space and ultimately lowers total system costs. SPI Serial Flash memory is manufactured with proprietary, high performance CMOS SuperFlash technology. The split-gate cell design and thick-oxide tunneling injector attain better reliability and manufacturability compared with alternate approaches. This Serial Flash significantly improves performance and reliability, while lowering power consumption. The device writes (Program or Erase) with a single power supply of 1.65-1.95V. The total energy consumed is a function of the applied voltage, current, and time of application. Since for any given voltage range, the SuperFlash technology uses less current to program and has a shorter erase time, the total energy consumed during any Program or Erase operation is less than alternative Flash memory technologies. SST25WF020A is offered in 8-lead SOIC, 8-contact USON, and 8-contact WDFN packages. See Figure 21 for the pin assignments. DS20005139F-page 1 SST25WF020A TO OUR VALUED CUSTOMERS It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and enhanced as new volumes and updates are introduced. If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via E-mail at docerrors@microchip.com. We welcome your feedback. Most Current Data Sheet To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at: http://www.microchip.com You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page. The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000). Errata An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision of silicon and revision of document to which it applies. To determine if an errata sheet exists for a particular device, please check with one of the following: • Microchip’s Worldwide Web site; http://www.microchip.com • Your local Microchip sales office (see last page) When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are using. Customer Notification System Register on our web site at www.microchip.com to receive the most current information on all of our products. DS20005139F-page 2  2014-2017 Microchip Technology Inc. SST25WF020A 1.0 FUNCTIONAL BLOCK DIAGRAM FIGURE 1-1: FUNCTIONAL BLOCK DIAGRAM SuperFlash Memory X - Decoder Address Buffers and Latches Y - Decoder I/O Buffers and Data Latches Control Logic Serial Interface CE# SCK SI SO WP# HOLD# 25139 F01.0  2014-2017 Microchip Technology Inc. DS20005139F-page 3 SST25WF020A 2.0 PIN DESCRIPTION FIGURE 2-1: PIN ASSIGNMENTS CE# 1 8 VDD SO 2 7 HOLD# WP# 3 6 SCK VSS 4 5 SI CE# 1 SO 2 Top View 8 VDD 7 HOLD# WP# 3 6 SCK VSS 4 5 SI 25139 08-uson Q3A P1.0 25139 08-soic-P0.0 8-Lead SOIC 8-Contact USON CE# 1 SO 2 8 VDD 7 HOLD# Top View WP# 3 6 SCK VSS 4 5 SI 20005139 08-WDFN MF P1.0 8-Contact WDFN TABLE 2-1: PIN DESCRIPTION Symbol Pin Name Functions SCK Serial Clock To provide the input/output timing of the serial interface. Commands, addresses, or input data are latched on the rising edge of the clock input, while output data is shifted out on the falling edge of the clock input. SI Serial Data Input To transfer commands, addresses, or data serially into the device. Inputs are latched on the rising edge of the serial clock. SO Serial Data Output To transfer data serially out of the device. Data is shifted out on the falling edge of the serial clock. CE# Chip Enable The device is enabled by a high-to-low transition on CE#. CE# must remain low for the duration of any command sequence. The device is deselected and placed in Standby mode when CE# is high. WP# Write Protect The Write-Protect (WP#) pin is used to enable/disable BPL bit in the status register. HOLD# Hold To temporarily stop serial communication with SPI Flash memory while device is selected. VDD Power Supply To provide power supply voltage: 1.65-1.95V for SST25WF020A VSS Ground DS20005139F-page 4  2014-2017 Microchip Technology Inc. SST25WF020A 3.0 MEMORY ORGANIZATION The SST25WF020A SuperFlash memory arrays are organized in 64 uniform 4 KByte sectors, with four 64 KByte overlay erasable blocks. MEMORY MAP Top of Memory Block 63 03FFFFH 03F000H 1 ... ... 01FFFFH 01F000H 16 ... 15 0 030FFFH 030000H 31 ... ... 48 1 0 ... 3 ... Number of Sectors 01FFFFH 010000H 00FFFFH 00F000H ... Number of 64 KByte Blocks ... FIGURE 3-1: 001FFFH 001000H 000FFFH 000000H Bottom of Memory Block 25139 F51.0 4.0 DEVICE OPERATION The SST25WF020A supports both Mode 0 (0,0) and Mode 3 (1,1) of SPI bus operations. The difference between the two modes, as shown in Figure 4-1, is the state of the SCK signal when the bus master is in Standby mode and no data is being transferred. The SCK signal is low for Mode 0 and SCK signal is high for Mode 3. For both modes, the Serial Data In (SI) is sampled at the rising edge of the SCK clock signal and the Serial Data Output (SO) is driven after the falling edge of the SCK clock signal. SST25WF020A is accessed through the SPI (Serial Peripheral Interface) bus compatible protocol. The SPI bus consist of four control lines; Chip Enable (CE#) is used to select the device, and data is accessed through the Serial Data Input (SI), Serial Data Output (SO), and Serial Clock (SCK). FIGURE 4-1: SPI PROTOCOL CE# SCK SI MODE 3 MODE 3 MODE 0 MODE 0 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 MSB SO HIGH IMPEDANCE DON'T CARE Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 MSB  2014-2017 Microchip Technology Inc. 25139 F03.0 DS20005139F-page 5 SST25WF020A 4.0.1 HOLD In the HOLD# mode, serial sequences underway with the SPI Flash memory are paused without resetting the clocking sequence. To activate the HOLD# mode, CE# must be in active low state. The HOLD# mode begins when the SCK active low state coincides with the falling edge of the HOLD# signal. The HOLD# mode ends when the rising edge of the HOLD# signal coincides with the SCK active low state. HOLD# must not rise or fall when SCK logic level is high. See Figure 4-2 for Hold Condition waveform. FIGURE 4-2: Once the device enters HOLD# mode, SO will be in high-impedance state while SI and SCK can be VIL or VIH. If CE# is driven active high during a Hold condition, the device returns to standby mode. The device can then be re-initiated with the command sequences listed in Table 5-1. As long as HOLD# signal is low, the memory remains in the Hold condition. To resume communication with the device, HOLD# must be driven active high, and CE# must be driven active low. See Figure 4-2 for Hold timing. HOLD CONDITION WAVEFORM SCK HOLD# Active Hold Active 25139 F05.1 4.1 Write-Protection SST25WF020A provides software write-protection. The Write-Protect pin (WP#) enables or disables the lockdown function of the status register. The BlockProtection bits (BP0, BP1, TB, and BPL) in the status 4.1.1 register provide write-protection to the memory array and the status register. See Table 4-3 for the Block-Protection description. WRITE-PROTECT PIN (WP#) The Write-Protect (WP#) pin enables the lock-down function of the BPL bit (bit 7) in the status register. When WP# is driven low, the execution of the Write- TABLE 4-1: Status-Register (WRSR) instruction is determined by the value of the BPL bit (see Table 4-1). When WP# is high, the lock-down function of the BPL bit is disabled. CONDITIONS TO EXECUTE WRITE-STATUS-REGISTER (WRSR) INSTRUCTION WP# BPL L 1 Not Allowed L 0 Allowed H X Allowed DS20005139F-page 6 Execute WRSR Instruction  2014-2017 Microchip Technology Inc. SST25WF020A 4.2 Status Register The software status register provides status on whether the flash memory array is available for any Read or Write operation, whether the device is Write enabled, and the state of the Memory Write protection. TABLE 4-2: During an internal Erase or Program operation, the status register may be read only to determine the completion of an operation in progress. Table 4-2 describes the function of each bit in the software status register. SOFTWARE STATUS REGISTER Default at Power-up Read/Write 1 = Internal Write operation is in progress 0 = No internal Write operation is in progress 0 R WEL 1 = Device is memory Write enabled 0 = Device is not memory Write enabled 0 R 2 BP01 Indicate current level of block write-protection (See Table 4-3) 0 or 1 R/W 3 BP11 Indicate current level of block write-protection (See Table 4-3) 0 or 1 R/W 4 RES Reserved for future use 5 TB1 1 = 1/4 or 1/2 Bottom Memory Blocks are protected (See Table 4-3) 0 = 1/2 or 1/4 Top Memory Blocks are protected 6 RES 7 1 Bit Name Function 0 BUSY 1 BPL Reserved for future use 1 = BP0, BP1, TB, and BPL are read-only bits 0 = BP0, BP1, TB, and BPL are read/writable 0 N/A 0 or 1 R/W 0 N/A 0 or 1 R/W 1. BP0, BP1, TB, and BPL bits are non-volatile memory bits. 4.2.1 BUSY (BIT 0) The Busy bit determines whether there is an internal Erase or Program operation in progress. A ‘1’ for the Busy bit indicates the device is busy with an operation in progress. A ‘0’ indicates the device is ready for the next valid operation. 4.2.2 bits as long as WP# is high or the Block-Protect-Lock (BPL) bit is ‘0’. Chip-Erase can only be executed if Block-Protection bits are all ‘0’. BP0 and BP1 select the protected area and TB allocates the protected area to the higher-order address area (Top Blocks) or lowerorder address area (Bottom Blocks). WRITE-ENABLE-LATCH (WEL–BIT 1) The Write-Enable-Latch bit indicates the status of the internal Write-Enable-Latch memory. If the WEL bit is set to ‘1’, it indicates the device is Write enabled. If the bit is set to ‘0’ (reset), it indicates the device is not Write enabled and does not accept any Write (Program/ Erase) commands. The Write-Enable-Latch bit is automatically reset under the following conditions: • • • • • • • Power-up Write-Disable (WRDI) instruction completion Page-Program instruction completion Sector-Erase instruction completion 64 KByte Block-Erase instruction completion Chip-Erase instruction completion Write-Status-Register instruction completion 4.2.3 BLOCK-PROTECTION (BP0, BP1, AND TB–BITS 2, 3, AND 5) The Block-Protection (BP0, BP1, and TB) bits define the size of the memory area to be software protected against any memory Write (Program or Erase) operation, see Table 4-3. The Write-Status-Register (WRSR) instruction is used to program the BP0, BP1, and TB  2014-2017 Microchip Technology Inc. DS20005139F-page 7 SST25WF020A 4.2.4 BLOCK-PROTECTION LOCK-DOWN (BPL–BIT 7) BP1, TB, and BPL bits. When the WP# pin is driven high (VIH), the BPL bit has no effect and its value is ‘Don’t Care’. When the WP# pin is driven low (VIL), it enables the Block-Protection Lock-Down (BPL) bit. When BPL is set to ‘1’, it prevents any further alteration of the BP0, TABLE 4-3: SOFTWARE STATUS REGISTER BLOCK-PROTECTION Status Register Bit Protection Level TB BP1 BP0 Protected Memory Address 0 (Full Memory Array unprotected) X 0 0 None T1 (1/4 Top Memory Block protected) 0 0 1 030000H-03FFFFH T2 (1/2 Top Memory Block protected) 0 1 0 020000H-03FFFFH B1 (1/4 Bottom Memory Block protected) 1 0 1 000000H-00FFFFH B2 (1/2 Bottom Memory Block protected) 1 1 0 000000H-01FFFFH 3 (Full Memory Array protected) X 1 1 000000H-03FFFFH DS20005139F-page 8  2014-2017 Microchip Technology Inc. SST25WF020A 5.0 INSTRUCTIONS Instructions are used to read, write (Erase and Program), and configure the SST25WF020A devices. The instruction bus cycles are 8 bits each for commands (Op Code), data, and addresses. The Write-Enable (WREN) instruction must be executed prior to SectorErase, Block-Erase, Page-Program, Write-Status-Register, or Chip-Erase instructions. The complete instructions are provided in Table 5-1. All instructions are synchronized off a high-to-low transition of CE#. Inputs will be accepted on the rising edge of SCK starting with TABLE 5-1: the most significant bit. CE# must be driven low before an instruction is entered and must be driven high after the last bit of the instruction has been shifted in (except for Read, Read-ID, and Read-Status-Register instructions). Any low-to-high transition on CE#, before receiving the last bit of an instruction bus cycle will terminate the instruction in progress and return the device to Standby mode. Instruction commands (Op Code), addresses and data are all input from the most significant bit (MSB) first. DEVICE OPERATION INSTRUCTIONS Address Dummy Data Maximum Cycle(s)2 Cycle(s) Cycle(s) Frequency Description Op Code Cycle1 Read Read Memory 0000 0011b (03H) 3 0 1 to  25 MHz High-Speed Read Read Memory at Higher Speed 0000 1011b (0BH) 3 1 1 to  40 MHz 4 KByte SectorErase3 Erase 4 KByte of memory array 0010 0000b (20H) 1101 0111b (D7H) 3 0 0 64 KByte BlockErase4 Erase 64 KByte block of memory array 1101 1000b (D8H) 3 0 0 Chip-Erase Erase Full Memory Array 0110 0000b (60H) or 1100 0111b (C7H) 0 0 0 Instruction Page-Program To program up to 256 Bytes 0000 0010b (02H) 3 0 1 to 256 5 RDSR Read-Status-Register 0000 0101b (05H) 0 0 1 to  WRSR Write-Status-Register 0000 0001b (01H) 0 0 1 WREN Write-Enable 0000 0110b (06H) 0 0 0 WRDI Write-Disable 0000 0100b (04H) 0 0 0 RDID6, 7 Read-ID 1010 1011b (ABH) 3 0 1 to  JEDEC-ID JEDEC ID Read 1001 1111b (9FH) 0 0 4 to  DPD Deep Power-Down Mode 1011 1001b (B9H) 0 0 0 RDPD7 Release from Deep PowerDown or Read-ID 1010 1011b (ABH) 0 0 0 1. 2. 3. 4. 5. 6. One bus cycle is eight clock periods. Address bits above the most significant bit of each density can be VIL or VIH. 4 KByte Sector-Erase addresses: use AMS-A12, remaining addresses are don’t care but must be set either at VIL or VIH. 64 KByte Block-Erase addresses: use AMS-A16, remaining addresses are don’t care but must be set either at VIL or VIH. The Read-Status-Register is continuous with ongoing clock cycles until terminated by a low-to-high transition on CE#. Device ID is read after three dummy address bytes. The Device ID output stream is continuous until terminated by a low-tohigh transition on CE#. 7. The instructions Release from Deep Power down and Read-ID are similar (ABH). Executing Read-ID requires the ABH instruction, followed by 24 dummy address bits to retrieve the Device ID. Release from Deep Power-Down only requires the instruction ABH.  2014-2017 Microchip Technology Inc. DS20005139F-page 9 SST25WF020A 5.1 Read (25 MHz) The Read instruction, 03H, supports up to 25 MHz Read. The device outputs a data stream starting from the specified address location. The data stream is continuous through all addresses until terminated by a lowto-high transition on CE#. The internal address pointer automatically increments until the highest memory address is reached. Once the highest memory address is reached, the address pointer automatically incre- FIGURE 5-1: ments to the beginning (wrap-around) of the address space. For example, for 2 Mbit density, once the data from the address location 3FFFFH is read, the next output is from address location 000000H. The Read instruction is initiated by executing an 8-bit command, 03H, followed by address bits A23-A0. CE# must remain active-low for the duration of the Read cycle. See Figure 5-1 for the Read sequence. READ SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 8 23 24 15 16 31 32 39 40 47 48 55 56 63 64 70 MODE 0 ADD. 03 SI ADD. ADD. MSB MSB N DOUT HIGH IMPEDANCE SO N+1 DOUT N+2 DOUT N+3 DOUT N+4 DOUT MSB 25139 F06.0 5.2 High-Speed-Read (40 MHz) The High-Speed-Read instruction supporting up to 40 MHz Read is initiated by executing an 8-bit command, 0BH, followed by address bits [A23-A0] and a dummy byte. CE# must remain active-low for the duration of the High-Speed-Read cycle. See Figure 5-2 for the High-Speed-Read sequence. through all addresses until terminated by a low-to-high transition on CE#. The internal address pointer will automatically increment until the highest memory address is reached. Once the highest memory address is reached, the address pointer will automatically increment to the beginning (wrap-around) of the address space. For example, for 2 Mbit density, once the data from address location 3FFFFH is read, the next output will be from address location 000000H. Following a dummy cycle, the High-Speed-Read instruction outputs the data starting from the specified address location. The data output stream is continuous FIGURE 5-2: HIGH-SPEED-READ SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 8 15 16 23 24 31 32 39 40 47 48 55 56 63 64 71 72 80 MODE 0 0B SI ADD. ADD. ADD. X MSB SO N DOUT HIGH IMPEDANCE N+1 DOUT N+2 DOUT N+3 DOUT N+4 DOUT MSB 25139 F07.0 DS20005139F-page 10  2014-2017 Microchip Technology Inc. SST25WF020A 5.3 Page-Program The Page-Program instruction programs up to 256 Bytes of data in the memory. The data for the selected page address must be in the erased state (FFH) before initiating the Page-Program operation. A Page-Program applied to a protected memory area will be ignored. Prior to the program operation, execute the WREN instruction. the internal, self-timed, Page-Program operation. See Figure 5-3 for the Page-Program sequence and Figure 6-9 for the Page-Program flow chart. When executing Page-Program, the memory range for the SST25WF020A is divided into 256-Byte page boundaries. The device handles the shifting of more than 256 Bytes of data by maintaining the last 256 Bytes as the correct data to be programmed. If the target address for the Page-Program instruction is not the beginning of the page boundary (A[7:0] are not all zero), and the number of bytes of data input exceeds or overlaps the end of the address of the page boundary, the excess data inputs wrap around and will be programmed at the start of that target page. To execute a Page-Program operation, the host drives CE# low, then sends the Page-Program command cycle (02H) and three address cycles, followed by the data to be programmed, then drives CE# high. The programmed data must be between 1 to 256 Bytes and in whole byte increments; sending less than a full byte will cause the partial byte to be ignored. Poll the BUSY bit in the Status register, or wait TPP, for the completion of FIGURE 5-3: PAGE-PROGRAM SEQUENCE CE# MODE 3 SCK 23 24 15 16 0 1 2 3 4 5 6 7 8 31 32 39 MODE 0 SI ADD. 02 MSB SO ADD. ADD. Data Byte 0 LSB MSB LSB MSB LSB HIGH IMPEDANCE 2079 2078 2077 2076 2075 2074 2073 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 2072 CE#(cont’) SCK(cont’) SI(cont’) Data Byte 1 MSB SO(cont’) Data Byte 255 Data Byte 2 LSB MSB LSB MSB LSB HIGH IMPEDANCE 25139 F60.1  2014-2017 Microchip Technology Inc. DS20005139F-page 11 SST25WF020A 5.4 Sector-Erase (AMS = Most Significant address) are used to determine the sector address (SAX), remaining address bits can be VIL or VIH. CE# must be driven high before the instruction is executed. Poll the BUSY bit in the Software Status register, or wait TSE, for the completion of the internal self-timed Sector-Erase cycle. See Figure 5-4 for the Sector-Erase sequence and Figure 6-9 for the flow chart. The Sector-Erase instruction clears all bits in the selected 4 KByte sector to FFH. A Sector-Erase instruction applied to a protected memory area will be ignored. Prior to any Write operation, the Write-Enable (WREN) instruction must be executed. CE# must remain active-low for the duration of any command sequence. The Sector-Erase instruction is initiated by executing an 8-bit command, 20H or D7H, followed by address bits [A23-A0]. Address bits [AMS-A12] FIGURE 5-4: SECTOR-ERASE SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 8 23 24 15 16 31 MODE 0 MSB ADD. ADD. 20 or D7 SI ADD. MSB SO HIGH IMPEDANCE 2539 F13.0 5.5 64-KByte Block-Erase The 64-KByte Block-Erase instruction clears all bits in the selected 64 KByte block to FFH. Applying this instruction to a protected memory area results in the instruction being ignored. Prior to any Write operation, the Write-Enable (WREN) instruction must be executed. CE# must remain active-low for the duration of any command sequence. Initiate the 64-Byte Block-Erase instruction by executing an 8-bit command, D8H, followed by address bits FIGURE 5-5: [A23-A0]. Address bits [AMS-A16] (AMS = Most Significant Address) determine the block address (BAX), remaining address bits can be VIL or VIH. CE# must be driven high before executing the instruction. Poll the Busy bit in the software status register or wait TBE for the completion of the internal self-timed Block-Erase cycle. See Figure 5-5 for the 64-KByte Block-Erase sequences and Figure 6-9 for the flow chart. 64-KBYTE BLOCK-ERASE SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 8 D8 SI MSB SO 15 16 23 24 31 MODE 0 ADDR ADDR ADDR MSB HIGH IMPEDANCE 25139 F15.0 DS20005139F-page 12  2014-2017 Microchip Technology Inc. SST25WF020A 5.6 Chip-Erase The Chip-Erase instruction clears all bits in the device to FFH. A Chip-Erase instruction is ignored if any of the memory area is protected. Prior to any Write operation, the Write-Enable (WREN) instruction must be executed. CE# must remain active-low for the duration of the Chip-Erase instruction sequence. Initiate the ChipErase instruction by executing an 8-bit command, 60H FIGURE 5-6: or C7H. CE# must be driven high before the instruction is executed. Poll the BUSY bit in the Software Status register, or wait TSCE, for the completion of the internal self-timed Chip-Erase cycle. See Figure 5-6 for the Chip-Erase sequence and Figure 6-11 for the flow chart. CHIP-ERASE SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 MODE 0 60 or C7 SI MSB SO HIGH IMPEDANCE 25139 F16.0 5.7 Read-Status-Register (RDSR) The Read-Status-Register (RDSR) instruction, 05H, allows reading of the status register. The status register may be read at any time even during a Write (Program/ Erase) operation. When a Write operation is in progress, the Busy bit may be checked before sending any new commands to assure that the new commands are FIGURE 5-7: properly received by the device. CE# must be driven low before the RDSR instruction is entered and remain low until the status data is read. Read-Status-Register is continuous with ongoing clock cycles until it is terminated by a low-to-high transition of the CE#. See Figure 5-7 for the RDSR instruction sequence. READ-STATUS-REGISTER (RDSR) SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 MODE 0 05 SI MSB SO HIGH IMPEDANCE Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 MSB Status Register Out 25139 F17.0  2014-2017 Microchip Technology Inc. DS20005139F-page 13 SST25WF020A 5.8 Write-Enable (WREN) The Write-Enable (WREN) instruction, 06H, sets the Write-Enable-Latch bit in the Status Register to 1 allowing Write operations to occur. The WREN instruction must be executed prior to any Write (Program/Erase) operation. The WREN instruction may also be used to allow execution of the Write-Status-Register (WRSR) FIGURE 5-8: instruction; however, the Write-Enable-Latch bit in the Status Register will be cleared upon the rising edge CE# of the WRSR instruction. CE# must be driven low before entering the WREN instruction, and CE# must be driven high before executing the WREN instruction. See Figure 5.8 for the WREN instruction sequence. WRITE-ENABLE (WREN) SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 MODE 0 06 SI MSB SO HIGH IMPEDANCE 25139 F18.0 5.9 Write-Disable (WRDI) The Write-Disable (WRDI) instruction, 04H, resets the Write-Enable-Latch bit to ‘0’, thus preventing any new Write operations. CE# must be driven low before enter- FIGURE 5-9: ing the WRDI instruction, and CE# must be driven high before executing the WRDI instruction. See Figure 5-9 for the WRDI instruction sequence. WRITE DISABLE (WRDI) SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 MODE 0 04 SI MSB SO HIGH IMPEDANCE 25139 F19.0 DS20005139F-page 14  2014-2017 Microchip Technology Inc. SST25WF020A 5.10 Write-Status-Register (WRSR) The Write-Status-Register instruction writes new values to the BP0, BP1, TB, and BPL bits of the status register. CE# must be driven low before the command sequence of the WRSR instruction is entered and driven high before the WRSR instruction is executed. Poll the BUSY bit in the Software Status register, or wait TWRSR, for the completion of the internal self-timed Write-Status-Register cycle. See Figure 5-10 for WREN and WRSR instruction sequences and Figure 7.0 for the WRSR flow chart. ‘1’ to lock-down the status register, but cannot be reset from ‘1’ to ‘0’. When WP# is high, the lock-down function of the BPL bit is disabled and the BPL, BP0, BP1, and TB bits in the status register can all be changed. As long as BPL bit is set to ‘0’ or the WP# pin is driven high (VIH) prior to the low-to-high transition of the CE# pin at the end of the WRSR instruction, the bits in the status register can all be altered by the WRSR instruction. In this case, a single WRSR instruction can set the BPL bit to ‘1’ to lock down the status register as well as altering the BP0, BP1, and TB bits at the same time. See Table 4-1 for a summary description of WP# and BPL functions. Executing the Write-Status-Register instruction is ignored when WP# is low and BPL bit is set to ‘1’. When the WP# is low, the BPL bit can only be set from ‘0’ to FIGURE 5-10: WRITE-ENABLE (WREN) AND WRITE-STATUS-REGISTER (WRSR) SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 MODE 0 MODE 3 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 MODE 0 06 SI MSB SO 01 MSB STATUS REGISTER IN 7 6 5 4 3 2 1 0 MSB HIGH IMPEDANCE 25139 F20.0  2014-2017 Microchip Technology Inc. DS20005139F-page 15 SST25WF020A 5.11 Power-Down The Deep Power-Down (DPD) instruction puts the device in the lowest power consumption mode – the Deep Power-Down mode. This instruction is ignored if the device is busy with an internal write operation. While the device is in DPD mode, all instructions are ignored except for the Release Deep Power-Down instruction or Read-ID. requires a delay of TDPD before the standby current ISB is reduced to the deep power-down current IDPD. See Figure 5-11 for the DPD instruction sequence. Exit the power-down state using the Release from Deep Power-Down or Read-ID instruction. CE# must be driven low before sending the Release from Deep Power-Down command cycle (ABH), and then driving CE# high. The device will return to Standby mode and be ready for the next instruction after TSBR. See Figure 5-12. for the Release from Deep Power-Down sequence. To initiate DPD, input the DPD instruction (B9H) while driving CE# low. CE# must be driven high before executing the DPD instruction. After driving CE# high, it FIGURE 5-11: DEEP POWER-DOWN SEQUENCE CE# TDPD MODE 3 SCK 0 1 2 3 4 5 6 7 MODE 0 B9 SI MSB SO HIGH IMPEDANCE 25139 F46.1 FIGURE 5-12: RELEASE FROM DEEP POWER-DOWN SEQUENCE CE# TSBR MODE 3 SCK 0 1 2 3 4 5 6 7 MODE 0 AB SI MSB SO HIGH IMPEDANCE 25139 F47.1 DS20005139F-page 16  2014-2017 Microchip Technology Inc. SST25WF020A 5.12 Read-ID The Read-ID instruction identifies the device as SST25WF020A. Use the Read-ID instruction to identify SST25WF020A when using multiple manufacturers in the same socket. See Table 5-2. Following the Read-ID instruction, and 24 address dummy bits, the device ID continues to output with continuous clock input until terminated by a low-to-high transition on CE#. See Figure 5-13 for the Read-ID sequence. The device ID information is read by executing an 8-bit command, ABH, followed by 24 dummy address bits. TABLE 5-2: PRODUCT IDENTIFICATION SST25WF020A ID FIGURE 5-13: Address Data XXXXXXH 34H READ-ID SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 8 23 24 15 16 31 32 39 40 47 48 55 56 63 MODE 0 XX AB SI XX MSB XX MSB HIGH IMPEDANCE SO Device ID Device ID Device ID Device ID HIGH IMPEDANCE MSB 25139 F22.1 Note: The Device ID output stream is continuous until terminated by a low-to-high transition on CE# 5.13 JEDEC Read-ID The JEDEC Read-ID instruction identifies the device ID information of SST25WF020A. The device information can be read by executing the 8-bit command, 9FH. Following the JEDEC Read-ID instruction, a 32-bit Device ID information is output from the device. The Device ID information is assigned by the manufacturer and contains the Device ID 1 in the first byte, the type of mem- FIGURE 5-14: ory in the second byte, the memory capacity of the device in the third byte, and a reserved code in the fourth byte. The 4-Byte code outputs repeatedly with continuous clock input until a low-to-high transition on CE#. See Figure 5-14 for the instruction sequence. The JEDEC Read ID instruction is terminated by a low-tohigh transition on CE# at any time during data output. JEDEC READ-ID SEQUENCE CE# MODE 3 SCK 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 MODE 0 SI SO 9F HIGH IMPEDANCE 16 62 MSB 12 00 MSB 25139 F23.1 TABLE 5-3: JEDEC READ-ID DATA-OUT Device ID Product SST25WF020A Device ID 1 (Byte 1) 62H  2014-2017 Microchip Technology Inc. Memory Type (Byte 2) 16H Memory Capacity (Byte 3) 12H Reserved Code (Byte 4) 00H DS20005139F-page 17 SST25WF020A 6.0 ELECTRICAL SPECIFICATIONS Absolute Maximum Stress Ratings (Applied conditions greater than those listed under “Absolute Maximum Stress Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these conditions or conditions greater than those defined in the operational sections of this data sheet is not implied. Exposure to absolute maximum stress rating conditions may affect device reliability.) Temperature Under Bias. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to +125°C Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to +150°C D. C. Voltage on Any Pin to Ground Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to VDD+0.5V Transient Voltage (