z80189 ZiLOG Semiconductor, z80189 Datasheet - Page 166

• Manufacturer Part Number: z80189
• Description: Z80180, Z8s180, Z8l180 Mpu Operation
• Manufacturer: ZiLOG Semiconductor

Figure 58.
CSI/O Operation
The CSI/O is operated using status polling or interrupt driven algorithms.
•
•
•
EIE
EF
Transmit–Polling
a. Poll the TE bit in CNTR until TE =
b. Write the transmit data into TRDR.
c. Set the TE bit in CNTR to
d. Repeat steps 1 to 3 for each transmit data byte.
Transmit–Interrupts
a. Poll the TE bit in CNTR until TE =
b. Write the first transmit data byte into TRDR.
c. Set the TE and EIE bits in CNTR to
d. When the transmit interrupt occurs, write the next transmit data
e. Set the TE bit in CNTR to
f.
Receive –Polling
a. Poll the RE bit in CNTR until RE =
b. Set the RE bit in CNTR to
byte into TRDR.
Repeat steps 4 and 5 for each transmit data byte.
CSI/O Interrupt Request Generation
IEF1
1
1
1
.
.
.
Family MPU User Manual
0
0
0
1
.
.
.
.
CSI/O
Interrupt Request
UM005003-0703
Z8018x
151