Intel 8XC196NT, User Manual

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C-59
REGISTERS
SSIOx_CON
SSIO
x
_CON
x = 0–1
Address:
Reset State:
Table C-15
The synchronous serial control x (SSIO x _CON) registers control the communications mode and
handshaking. The two least-significant bits indicate whether an overflow or underflow has occurred
and whether the channel is ready to transmit or receive.
7 0
M/S# T/R# TRT THS STE ATR OUF TBS
Bit
Number
Bit
Mnemonic
Function
7
†
M/S# Master/Slave Select
Configures the channel as either master or slave.
0 = slave; SC x is an external clock input to SSIO x _BUF
1 = master; SC x is an output driven by the SSIO baud-rate generator
6
†
T/R# Transmit/Receive Select
Configures the channel as either transmitter or receiver.
0 = receiver; SD
x
is an input to SSIO
x
_BUF
1 = transmitter; SD x is an output driven by the output of SSIO x _BUF
5 TRT Transmitter/Receiver Toggle
Controls whether receiver and transmitter switch roles at the end of each
transfer.
0 = do not switch
1 = switch; toggle T/R# and clear TRT at the end of the current transfer
Setting TRT allows the channel configuration to change immediately on
transfer completions, thus avoiding possible contention on the data line.
4 THS Transceiver Handshake Select
Enables and disables handshaking. The THS, STE, and ATR bits must be
set for handshaking modes.
0 = disables handshaking
1 = enables handshaking
3 STE Single Transfer Enable
Enables and disables transfer of a single byte. Unless ATR is set, STE is
automatically cleared at the end of a transfer. The THS, STE, and ATR
bits must be set for handshaking modes.
0 = disable transfers
1 = allow transmission or reception of a single byte.
2 ATR Automatic Transfer Re-enable
Enables and disables subsequent transfers. The THS, STE, and ATR bits
must be set for handshaking modes.
0 = allow automatic clearing of STE; disable subsequent transfers
1 = prevent automatic clearing of STE; allow transfer of next byte
†
The M/S# and T/R# bits specify four possible configurations: master transmitter, master receiver,
slave transmitter, or slave receiver.