OP7100
Hardware 43
Z180 Serial Ports
The
Z180
’s two independent, full-duplex asynchronous serial channels
have a separate baud-rate generator for each channel. The baud rate can be
divided down from the microprocessor clock, or from an external clock for
either or both channels.
The serial ports have a multiprocessor communications feature. When
enabled, this feature adds an extra bit to the transmitted character (where
the parity bit would normally go). Receiving
Z180
s can be programmed to
ignore all received characters except those with the extra multiprocessing
bits enabled. This provides a
1
-byte attention message that can be used to
wake up a processor without the processor having to intelligently monitor
all traffic on a shared communications link.
The block diagram in Figure 3-22 shows Serial Channel 0. Serial Chan-
nel 1 is similar, but control lines for
/RTS
and
/DCD
do not exist. The five
unshaded registers shown in Figure 3-22 are directly accessible as internal
registers.
Figure 3-22. Z180 Serial Channel 0
Microprocessor Internal Bus
RDR0
TDR0
TSR0
RXA0
TXA0
Shift Register Out
Shift Register In
Baud-Rate
Generator
CKA0
CNTLA0
STAT0
CNTLB0
/RTS0
/CTS0
/DCD0
RSR0
Summary of Contents for OP7100
Page 1: ...OP7100 Serial Graphic Display User s Manual 019 0065 070831 O ...
Page 10: ...OP7100 x About This Manual ...
Page 16: ...OP7100 16 Overview ...
Page 74: ...OP7100 74 Software ...
Page 82: ...OP7100 82 Graphics Programming ...
Page 88: ...OP7100 88 Installation ...
Page 98: ...OP7100 98 Specifications ...
Page 108: ...OP7100 108 Memory I O Map and Interrupt Vectors ...
Page 112: ...112 Serial Interface Board 2 OP7100 ...
Page 113: ...OP7100 Backup Battery 113 APPENDIX E BACKUP BATTERY ...
Page 116: ...OP7100 116 Backup Battery ...
Page 124: ...OP7100 124 Index ...
Page 126: ...XX0000 Schematics ...