Zilog Z80180 - Manual (Page 167)

Z8018x
Family MPU User Manual
152
UM005003-0703
c. Poll the RE bit in CNTR until RE =
0
.
d. Read the receive data from TRDR.
e. Repeat steps 2 to 4 for each receive data byte.
•
Receive–Interrupts
a. Poll the RE bit in CNTR until RE is
0
.
b. Set the RE and EIE bits in CNTR to
1
.
c. When the receive interrupt occurs read the receive data from
TRDR.
d. Set the RE bit in CNTR to
1
.
e. Repeat steps 3 and 4 for each receive data byte.
CSI/O Operation Timing Notes
•
Transmitter clocking and receiver sampling timings are different from
internal and external clocking modes. Figure 59 to Figure 62 illustrate
CSI/O Transmit/Receive Timing.
•
The transmitter and receiver is disabled TE and RE =
0
) when
initializing or changing the baud rate.
CSI/O Operation Notes
•
Disable the transmitter and receiver (TE and RE =
0
) before
initializing or changing the baud rate. When changing the baud rate
after completion of transmission or reception, a delay of at least one
bit time is required before baud rate modification.
•
When RE or TE is cleared to
0
by software, a corresponding receive
or transmit operation is immediately terminated. Normally, TE or RE
is only cleared to
0
when EF is
1
.
•
Simultaneous transmission and reception is not possible. Thus, TE
and RE are not both
1
at the same time.