Appendix E
Memory Map
128
Communication Flags
Communication Input Flags
Address
$0015
START
/
STOP
____
____
CTS1
DSR2
DSR1
BAT
LOW
1
IRQ2
IRQ1
___
___
___
___
___
7
6
5
4
3
2
1
0
Port for interrupts from ACIA and PTM
Port for interrupts from START/STOP
switch and PC
0 when START/STOP switch is ON
Normally 1
1 when battery voltage drops
Port 1 DSR signal, active low
Port 2 DSR signal, active low
Port 1 CTS signal, active low
Communication Output Flags
Address
$0003
BANK2 BANK1 WDREF
DTR2
DTR1
___
___
7
6
5
4
3
2
1
0
TXD1
RXD1
RTS1
___
Port 1 DTR signal, active low
Port 2 DTR signal, active low
1 RTS signal, active low
1 receive data
Port 1 transfer data
Watchdog timer refresh port
Bank ports (Do not change
these ports.)
Summary of Contents for C500-ASC04
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