Typewriter User Manual

MOTOROLA MC68340 USER’S MANUAL 7- 37
OP0—Output Port 0/RTSA
1 = The OP0/RTSA pin functions as the ready-to-send signal for channel A. The
signal is asserted and negated according to the configuration programmed by
RxRTS bit 7 in the MR1A for the receiver and TxRTS bit 5 in the MR2A for the
transmitter.
0 = The OP0/
RTSA pin functions as a dedicated output. The signal reflects the
complement of the value of bit 0 of the OP.
7.4.1.16 OUTPUT PORT DATA REGISTER (OP). The bits in the OP register are set by
performing a bit set command (writing to offset $71E) and are cleared by performing a bit
reset command (writing to offset $71F). This register can only be written when the serial
module is enabled (i.e., the STP bit in the MCR is cleared).
Bit Set
OP $71E
76543210
OP7 OP6 OP5 OP4 OP3 OP2 OP1 OP0
RESET:
00000000
Write Only Supervisor/User
NOTE
OP bits 7, 5, 3, and 2 are not pinned out on the MC68340;
thus, changing these bits has no effect.
OP6, OP4, OP1, OP0—Output Port Parallel Outputs
1 = These bits can be set by writing a one to the bit position(s) at this address.
0 = These bits are not affected by writing a zero to this address.
Bit Reset
OP $71F
76543210
OP7 OP6 OP5 OP4 OP3 OP2 OP1 OP0
RESET:
00000000
Write Only Supervisor/User
NOTE
OP bits 7, 5, 3, and 2 are not pinned out on the MC68340;
thus, changing these bits has no effect.
OP6, OP4, OP1, OP0—Output Port Parallel Outputs
1 = These bits can be cleared by writing a one to the bit position(s) at this address.
0 = These bits are not affected by writing a zero to this address.
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
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