Wang 5536 - Page 38

3402
scs
EP
PEN
12,Ll
82,Sl
CRD
Single Character Synchronization (Double if not· set)
Even Parity Generate/Check (if PEN set)
Parity Enable
Transmission Character Length (in bits):
00 = 5; 01 = 6; 10 = 7 i 11 = 8
Number of Stop Bits: 00 = Invalid; 01 = l; 10 = 1-1/2; 11.= 2
Clock Rate Divider (see description of the command which
sets the clock rate for values to use)
Command Word
DO TxE
Dl DTR
D2 RxE
D3 BRK
D4 ER
D5 RTS
D6 IR
D7 EH
EH Enter Hunt Mode (applicable to synchronous only)
IR Internal Rest USART
RTS
ER
BRK
RxE
DTR
TxE
Request to Send Modem Signal
Error Reset of Framing, Overrun, and Parity Error Status
Send Break on Transmit Data Signal
(Break lasts until BRK is cleared)
Receive Enable
Data Terminal Read Modem Signal
Transmit Enable
The USART chip has several limitations which must be observed.
o The status of the USART will not be valid until 28 clock cycles from an
event affecting the status (11.4 microseconds).
o The TXRDY pin will not be valid for 8 clock cycles after last trans-
mission (3.25 microseconds).
o The RXRDY pin will not be valid for up to 24 clock cycles after the last
received character. (9.77 microseconds).
o Note also that the main USART clock is independent of the system clock
and has a fixed frequency of 2.4576 MHZ.
2.4.4.3 Modem Interface
The workstation contains a 25-pin connector EIA RS-232-C.
Control
Signal
ON
OFF
Data I
Signal I
SPACE ( O) I
MARK (1) I
Applied
Voltage
2-24
+8
-8
Detected
Voltage
+5 to + 15
-5 to - 15
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