Model 100 Serial Interface
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Overview
The BASIC ROM provides access to the serial port. This support is well documented elsewhere. This article covers direct use of the IM6402 UART.
Configuration
Serial Word Format
Port $D8 controls the serial word format.
Bit
Function
Note
0
Stop bits
0 → 1 stop bit
1 → 2 or 1.5 stop bits (1.5 if character length is 5, 2 otherwise)
1
Parity
0 → Odd parity
1 → Even
2
Parity Inhibit
0 → Parity
1 → No parity
4-3
Character length
Number of bits:
00 → 5
01 → 6
10 → 7
11 → 8
7-5
Unused
Baud Rate
Data Transmission
Data Reception
I/O Map
Name Direction Port TX Output $C8 RX Input $C8 RTS Output $BA, bit 7 CTS Input $BB, bit 4 DSR Input $BB, bit 5 DTR Output $BA, bit 6
Direction indicates both data flow, and whether to use an IN or OUT instruction to read/write to the given pin.
