Features, Applications
Pin compatible with MAS7838 Interfaces a duplex asynchronous to synchronous channel Modem speeds 14.4k, 19.2k and 38.4k bps with a single 4.9152 MHz crystal
DESCRIPTION
is a single chip duplex asynchronous to synchronous converter. It converts asynchronous start stop characters to synchronous format, with stop bit deletion when required as defined in the CCITT recommendation V.14. On the receiver channel MAS9138 converts the incoming synchronous data to asynchronous start stop character format with stop bit insertion when required as defined in the CCITT recommendation V.14. MAS9138 implements the data modes for the synchronous interface as specified in the V.14. MAS9138 can be configured to operate at any frequency to 38.4 kbits/s within these modes. The device contains a bit generator and frequency selection logic to allow easy operation at other data rates. With just one crystal the device can adapt to ten (10) different bit rates it is ideally suited to be used with the most common modem systems ranging from to V.34.
FEATURES
Implements CCITT recommendation V.14 Bypass operation Character length from to 11 bits including start stop and parity bits CMOS and LS-TTL compatible interface Low power consumption (typically 10 mW) No additional circuitry needed to perform conversion Single +3.3...+5V supply o Operating temperature C 16-pin PDIP and SO package
APPLICATION
Data communication systems Adapts asynchronous terminals to synchronous modems Full or half card PC modems using UART as a data source Simplifying data multiplexing systems
Top marking: YYWW = Year Week, XXXXX.X = Lot Number,
Pin name TSL TMG I/O I Function Timing select. 0 selects external sampling timing 16 x TXC from pin 2, TMG. 1 selects internal sampling timing. Timing. Square wave timing signal 16 x TXC (TSL 128 x TXCmax (TSL = 1). Max = 10 Mhz when VDD = 5v and 5MHz when VDD = 3.3v. Oscillator. Output for crystal. If used, the crystal is connected between pins 2 and 3. Transmitter timing (MAS9138 only). Synchronous square wave timing for transmitter. The transmitted data output, TDO is synchronized to the rising edge of TXC. The duty cycle of TXC has 50% 5%. Character length. The total character length including one start bit, one stop bit and possible parity bit is selected with the CL1 and CL2 signals. Extended signalling rate. The tolerance of the synchronous bit rate can be: XESR = 1 (basic signalling rate) TXC -2.5%...+1.0% XESR = 0 (extended signalling rate) TXC -2.5%...2.3% Ground
Pin name TDI TDO XASY Pin no. PDIP O I Transmitter data input. 1 = mark or stop bit. 0 = space, start or break signal. Transmitter data output. Output data is synchronized to the synchronous timing signal TXC (pin 1 = mark. 0 = space. Asynchronous mode. XASY = 0 Asynchronous transmission, XASY = 1 Synchronous transmission. In synchronous transmission the converter is totally bypassed in both directions: TDI = TDO, RDI = RDO Higher speed signalling timing. XHST = 1 normal synchronous to asynchronous conversion (CCITT V.14). XHST = 0 asynchronous to synchronous conversion with higher speed synchronous timing (TXC, RXC). TXC and RXC timing must be 1-2% higher than the normal bit rate in order to allow some overspeed in the asynchronous data. On the receiver side the RX buffer is deleted and the synchronous data RDI is directly connected to the asynchronous output RDO. Receiver data output. RDO is the received data converted back to asynchrnous mode. 1 = mark or stop bit, 0 = space, start or break signal Receiver data input. 1 = mark, 0 = space. The received data must be synchronized to the receiver timing RXC from the synchronous channel (pin 15). Receiver timing (MAS9138 only). Receiver square wave timing from the synchronous channel. The received data RDI must be synchronized to the rising edge of RXC. Power supply I/O Function
Parameter Supply Voltage Supply current Operating Temperature Symbol VDD IDD Ta VDD = 5V Conditions Min 2 -40 Typ to 5.0 Max 5 +85 Unit V mA
