OP7100
Hardware 47
ASCI Control Register A
Control Register A affects various aspects of the asynchronous channel
operation.
CNTLA0
(00H)
7
6
5
4
3
2
1
0
MPE
RE
TE
/RTS0
MPBR/
EFR
MOD2
MOD1
MOD0
R / W
R / W
R / W
R / W
R / W
R / W
R / W
R / W
CNTLA1
(01H)
7
6
5
4
3
2
1
0
MPE
RE
TE
CKA1D
MPBR/
EFR
MOD2
MOD1
MOD0
R / W
R / W
R / W
R / W
R / W
R / W
R / W
R / W
MOD0–MOD2 (Data Format Mode Bits)
MOD0 controls stop bits: 0
⇒
1 stop bit, 1
⇒
2 stop bits. If 2 stop bits are
expected, then 2 stop bits must be supplied.
MOD1 controls parity: 0
⇒
parity disabled, 1
⇒
parity enabled. (See PEO
in ASCI Control Register B for even/odd parity control.)
MOD2 controls data bits: 0
⇒
7 data bits, 1
⇒
8 data bits.
MPBR/EFR (Multiprocessor Bit Receive/Error Flag Reset)
Reads and writes on this bit are unrelated. Storing a byte when this bit is 0
clears all the error flags (OVRN, FE, PE). Reading this bit obtains the
value of the MPB bit for the last read operation when the multiprocessor
mode is enabled.
/RTS0 (Request to Send, Channel 0)
Store a 1 in this bit to set the RTS0 line from the Z180 high. This bit is
essentially a 1-bit output port without other side effects.
CKA1D (CKA1 Disable)
This bit controls the function assigned to the multiplexed pin (CKA1/
~TEND0): 1
⇒
~TEND0 (a DMA function) and 0
⇒
CKA1 (external
clock I/O for Channel 1 serial port).
TE (Transmitter Enable)
This bit controls the transmitter: 1
⇒
transmitter enabled, 0
⇒
transmitter
disabled. When this bit is cleared, the processor aborts the operation in
progress, but does not disturb TDR or TDRE.
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 ...