Motorola MPC860 PowerQUICC, User Manual, Page: 809 / 1106

MOTOROLA Chapter 30. Serial Management Controllers 30-19
Part V. The Communications Processor Module
Figure 30-10 shows an example of the timing of various events in the SMCE.
Figure 30-10. SMC UART Interrupts Example
30.3.13 SMC UART Controller Programming Example
The following initialization sequence assumes 9,600 baud, 8 data bits, no parity, and 1 stop
bit in a 25-MHz system. BRG1 and SMC1 are used.
1. ConÞgure the port B pins to enable SMTXD1 and SMRXD1. Set PBPAR[24, 25]
then clear PBDIR[24, 25] and PBODR[24, 25].
2. ConÞgure the BRG1. Write BRGC1 with 0x01_0144. The DIV16 bit is not used and
the divider is 162 (decimal). The resulting BRG1 clock is 16
´
the preferred bit rate.
3. Connect BRG1 to SMC1 using the SI. Clear SIMODE[SMC1, SMC1CS].
4. Assuming one RxBD at the beginning of dual-port RAM followed by one TxBD,
write RBASE with 0x0000 and TBASE with 0x0008.
5. Write 0x0091 to CPCR to execute the
INIT RX AND TX PARAMETERS
command.
6. Initialize the SDMA conÞguration register (SDCR) to 0x0001.
7. Write RFCR and TFCR with 0x10 for normal operation.
8. Write MRBLR with the maximum number of bytes per receive buffer. Assume 16
bytes, so MRBLR = 0x0010.
9. Write MAX_IDL with 0x0000 in the SMC UART-speciÞc parameter RAM to
disable the MAX_IDL functionality for this example.
10. Clear BRKLN and BRKEC in the SMC UART-speciÞc parameter RAM.
RX RX BRK BRKE
Break
Line Idle
10 Characters
RXD
Characters
Received by SMC UART
Time
Line Idle
TXD
Characters
Transmitted by SMC UART
TX
Line Idle Line Idle
7 Characters
NOTES:
SMC UART SMCE
Events
1. The Þrst RX event assumes receive buffers are 6 bytes each.
2. The second RX event position is programmable based on the MAX_IDL value.
3. The BRK event occurs after the Þrst break character is received.
SMC UART SMCE
Events
NOTES:
The TX event assumes all seven characters were put into a single buffer, and the TX event occurred when the seventh
character was written to the SMC transmit FIFO. 1.