SI2400URT-EVB

S i 2 4 0 0 U R T- E V B E V A L U A T I O N B O A R D F O R T H E S i2 4 0 0 W I T H A UART I N T E R F A C E Description The Si2400URT-EVB evaluation board provides the system designer an easy way to evaluate the Si2400 ISOmodem™. The Si2400URT-EVB consists of a motherboard with a power supply, an RS-232 interface, other ease-of-use features, and a complete removable modem module on a daughter card. (A functional block diagram of the Si2400URT-EVB is shown below.) The Si2400 ISOmodem is a complete controller-based modem chipset with an integrated and programmable direct access arrangement (DAA) that meets global telephone line requirements. Available as two 16-pin small outline (SOIC) packages, the Si2400 ISOmodem eliminates the need for a separate DSP data pump, modem controller, memories, analog front end (AFE), isolation transformer, relays, opto-isolators, and a 2- to 4-wire hybrid. The Si2400 is ideal for embedded modem applications due to its small board area, controllerbased architecture, low power consumption, and global compliance. The Si2400URT-EVB provides an RJ-11 jack and a DB9 connector for interfacing the Si2400URT-EVB to the phone line and a PC or data terminal serial port. This allows the Si2400 ISOmodem to operate as a serial modem for straightforward evaluation. To evaluate the Si2400 ISOmodem in an embedded system, the daughter card can be used independently or with the motherboard. A direct access header (JP3) is available on the motherboard to bypass the RS-232 transceivers and connect the Si2400 ISOmodem directly to a target system. The EVB also provides test points for access to the analog input and analog output. These interfaces can be used to evaluate the Si2400 PCM and voice modes. Given that any of the GPIO pins may be used as an audio input, the EVB provides access to all GPIO pins. Power is supplied through a screw terminal (J3) or a standard 2 mm power jack (J4). An on-board rectifier, filter, and voltage regulator allow the power input to be 7.5 V–13 V ac or dc (either polarity). The Si2400URTEVB can drive an external speaker for call monitoring or a piezoelectric speaker can be mounted directly on the board in the space provided. Features The Si2400URT-EVB includes the following: Dual RJ-11 connection to phone line Serial interface to PC Audio connector for call monitoring Direct access to Si2400 for embedded application evaluation Easy power connection to common 7.5 V–13.5 V power supplies 9 V ac adaptor Simple installation and operation Functional Block Diagram Audio Out 9 V dc at 300 mA ac Adaptor 7.5–13.5 V dc or peak ac UART Rectifier Filter Audio Amplifier Voltage Regulator 3.3 V Direct Access HDR Daughter Board Boundary 5V DB9 RS-232 Transceivers AOUT Interface Selection Jumpers Si2400 RESET XTALO Si3015 Interface Circuit RJ-11 Phone Line XTALI Push Button Reset Power-On Reset Rev. 0.6 10/01 Copyright © 2001 by Silicon Laboratories Si2400URT-EVB-06 Si2400URT-EVB Introduction Table 2. Modem Initialization Example Notable differences between the Si2400 and other ISOmodem products are highlighted in the bulleted list below. For complete details and specifications, please refer to the current Si2400 data sheet. Unique Si2400 Features: Many AT commands execute when entered without AT COMMANDS MUST BE ENTERED IN UPPER CASE The +++ escape sequence is disabled at power-up and/or reset ATS14=20 enables +++ escape S-Register address and value are entered in hex (example: ATS0F=2B) Result codes are abbreviated (example: “O” instead of “OK”) The Si2400DC power can be 3.3 V or 5 V (3.3 V used on motherboard) Several AT commands are required to enable the speaker Auto-answer after two rings ATS07=06 Configures modem for V.22b ATS14=20 Enables +++ escape ATSF4=00 Removes audio mute ATSE4=02 Turns on audio ADC and DAC ATM1 Turns on speaker until carrier negotiated Si2400URT-EVB Setup and Evaluation This section explains how to set up the Si2400URT-EVB for evaluation as a serial interface modem. Jumper settings, power connection, PC/terminal connections, and terminal program configuration settings are given. The initial modem setup after power is applied along with a basic tutorial on modem operation is also provided. Si2400URT-EVB configurations for evaluating additional features are discussed separately. 1. Set jumpers according to Figure 1 DTE interface default is 8N1, 2400 bps, no handshaking and no line-feeds with carriage returns ATDT is disabled if line-feeds with carriage returns are enabled Some common AT Commands are not available ATH1 A/ ATD (must be ATDT or ATDP) AT&Tn (use ATSE4=20 for local digital loopback) Table 1. Modem Configuration Examples 2 ATS00=02 Si2400URT-EVB Quick Start ATSF4=00 removes Tx and Rx audio mute ATSE4=02 turns on ADC and DAC power ATM2 turns on speaker continuously Modulation Command Function 2. Connect DB-9 to PC COM 1 (with a pass-through cable) RJ-11 to phone line or test box the 9 V ac adaptor 3. Bring up Turn on power to modem Set Terminal Program for 2400 bps 8N1. No handshaking. Disable linefeeds with carriage returns (linefeeds with carriage returns disable ATDT commands.) 4. Type “AT” followed by a carriage return. Should echo “AT” and then an “O”. 5. Type ATS14=20 to enable +++ escape ATS07=06 to enable V.22b ATS00=01 for auto-answer on first ring ATS07= V22bis 06 V.22 02 V.21 03 Bell 212A 00 Bell 103 01 V.23 (1200 TX, 75 RX—Answer) 14 V.23 (75 TX, 1200 RX—Originate) 24 V.23 (600 TX, 75 RX—Answer) 10 V.23 (75 TX, 600 RX—Originate) 20 Rev. 0.6 Si2400URT-EVB Jumper Settings Check all jumper settings on the Si2400URT-EVB before applying power. Figure 1 shows the standard factory jumper settings. These settings configure the Si2400URT-EVB for RS-232 serial operation. Any standard terminal program configured to communicate through a PC COM port can be used to communicate with the Si2400URT-EVB. The transceiver jumper (JP8) should be connected whenever the RS-232 UART interface is used. For normal operation, JP6 should have jumpers at positions 2-3, 5-6, 8-9, and 11-12. ALERT/GPIO4 (Si2400, pin 10) is connected to RD (ring detect) (J1, pin 9) on the PC by via the jumper at JP6 pins 5-6. Removing this jumper disconnects RD from the ALERT/GPIO4 pin on the Si2400. Placing a jumper at JP6 (pins 2-3) and JP5 (pins 2-3) connects EOFR/GPIO1 (Si2400, pin 16) to CD (J1, pin 1). Placing a jumper at JP6 (pins 2-3) and JP5 (pins 1-2) connects CD/AIN/GPIO2 (Si2400, pin 15) to CD (J1, pin 1). Figure 1. Standard Factory Jumper Settings (outlined in gray) Rev. 0.6 3 Si2400URT-EVB Power Requirements The Si2400URT-EVB has an on-board diode bridge, filter capacitor, and voltage regulator (U8). Power can be supplied from any source capable of providing 7.5 V–13 V dc or 7.5 V–13 V peak ac and at least 100 mA. (Additional current may be required if a speaker is connected for monitoring call progress tones.) Power may be applied to the Si2400URT-EVB through the screw terminals (J3) or the 2 mm power jack (J4). The on-board full-wave rectifier and filter ensures the correct polarity is applied to the Si2400URT-EVB. Daughter card power is supplied through voltage regulator U7 and is factory set at 3.3 V by connecting JP7 pins 1 and 2. Daughter card current can be measured by connecting an ammeter between JP7 pins 1 and 2. These pins must always be connected. Failure to connect pins 1 and 2 of JP7 through either a jumper or a low impedance ammeter may result in damage to the Si2400URT-EVB. Terminal and Line Connections The Si2400 can be tested as a standard serial data modem by connecting the Si2400URT-EVB to a personal computer or other data terminal equipment (DTE), phone line, and power. Connect a serial port on a PC to the DB9 connector on the Si2400URT-EVB with a pass-through cable. The RS-232 transceivers on the EVB can communicate with the DTE at rates up to 230.4 kbps. Any standard terminal program such as HyperTerminal or ProComm running on a PC will communicate with the Si2400URT-EVB. Configure the terminal emulation program to 2400 bps, 8 data bits, no parity, one stop bit, and no handshaking. Also, be sure to disable linefeeds with carriage returns. Connect the RJ-11 jack on the Si2400URT-EVB to an analog phone line or telephone line simulator such as a Teltone TLS 5. Making Connections With the terminal program properly configured and running, apply power to the Si2400URT-EVB. Type “AT” and the modem should return “O” indicating the modem is working in the command mode and communicating with the terminal. If the “O” response is not received, try resetting the modem by pressing the manual reset switch (S1) then again type “AT”. To take the modem off-hook, type “ATDT.” The modem should go to the off-hook state, draw loop current, and respond with a “t”, indicating a dial tone detection. Typing any characters will make the modem hang up (go on-hook) and stop drawing loop current. To make a modem connection, type “ATDT(called modem phone number).” Once the connection is established, a “c” message will appear indicating the 4 two modems are in the data mode and communicating. Typing on one terminal should appear on the other terminal. To return to the command mode without interrupting the connection between the two modems, type “+++.” Approximately two seconds later “O” will appear. The modem is now in command mode and will accept “AT” commands. This assumes the command ATS14=20 was issued during the initial modem configuration to enable “+++” escape. To return to the data mode, type “ATO.” The modem will resume the data connection and no longer accept AT commands. Type “ATH” to terminate the data connection. Echo control effects data and command mode. To turn off the character echo, type “ATEO”. Si2400URT-EVB Functional Description The Si2400URT-EVB is a multipurpose evaluation system. The modem daughter card illustrates the small size and few components required to implement an entire controller-based modem with global telecommunications compatibility. The daughter card can be used independently of, or in conjunction with, the motherboard. The motherboard adds features that enhance the ease of evaluating the many capabilities of the Si2400 ISOmodem™. Motherboard The motherboard provides a convenient interface to the Si2400DC (daughter card). The versatile power supply allows for a wide range of ac and dc voltages to power the board. RS-232 transceivers and a DB9 connector allow the Si2400URT-EVB to be easily connected to a PC or other terminal device. Jumper options allow direct access to the LVCMOS/TTL level serial inputs to the Si2400, bypassing the RS-232 transceivers. This is particularly useful for directly connecting the Si2400 to embedded systems. The Si24xxURT-EVB motherboard connects to the daughter card through two connectors, JP1 and JP2. JP1 is an 8x2 socket providing connection to all Si2400 digital signals and regulated 3.3 V power for the Si2400. The Si2400 digital signals appearing at JP1 (daughter card interface) are LVCMOS and TTL compatible. The Si2400DC can be powered by 5.0 V or 3.3 V. The motherboard is factory configured for 3.3 V. It is recommended that JP7 pins 1 and 2 are connected any time the daughter card is used in conjunction with the motherboard. This ensures no damage will occur to the Si2456/33/14DC if used with this motherboard. JP2 is a 4x1 socket providing connection between the daughter card, the RJ-11 phone jack and chassis ground. Rev. 0.6 Si2400URT-EVB Voltage Regulator/Power Supply The input voltage to either J3 or J4 must be between 7.5 and 13.5 V dc or 7.5 and 13.5 VPEAK ac. The motherboard includes a diode bridge (D1–D4) to guard against a polarity reversal of the dc voltage or to rectify an ac voltage. The power source must be capable of continuously supplying at least 100 mA. C50 serves as a filter cap for an ac input. The voltage regulator U8 provides 5 V for the motherboard and the input for voltage regulator U7 which outputs 3.3 V for use on the motherboard and to power the daughter card. Si24xxDC power consumption can be measured by placing a meter between pins 1 and 2 of JP7. The connection between JP7 pins 1 and 2 must be made at all times when power is applied to the evaluation board either through a jumper block or a low impedance meter to avoid damage to the daughter card. or any other Data Terminal Equipment (DTE) via a standard RS-232 interface or through a direct TTL serial interface. The Si2400 can be tested as a standard data modem by connecting the Si2400URT-EVB to a personal computer or other DTE, power and a phone line. The RS-232 transceivers on the Si2400URT-EVB can communicate at rates between 300 bps and 230.4 kbps. A PC can communicate with the Si2400URT-EVB using a standard terminal program such as HyperTerm or ProComm. Jumper settings determine how the Si2400URT-EVB is connected to the DTE. Table 3 lists the interface controlled by each motherboard jumper. See Figures 6 and 11. Table 3. Interface Selection Jumpers Reset Circuitry The Si2400 requires a reset pulse to remain low for at least 5.0 ms after the power supply has stabilized during the power-up sequence or for at least 5.0 ms during a power-on reset then go high with a rise time