Motorola MPC8260 - Manual (Page 715)

MOTOROLA Chapter 26. Serial Management Controllers (SMCs) 26-19
Part IV. Communications Processor Module
Figure 26-10. SMC UART Interrupts Example
26.3.12 SMC UART Controller Programming Example
The following initialization sequence assumes 9,600 baud, 8 data bits, no parity, and 1 stop
bit in a 66-MHz system. BRG1 and SMC1 are used. (The SMC transparent programming
example uses an external clock conÞguration; see Section 26.4.11, ÒSMC Transparent
NMSI Programming Example.Ó)
1. ConÞgure the port D pins to enable SMTXD1 and SMRXD1. Set PPARD[8,9] and
PDIRD[9]. Clear PDIRD[8] and PSORD[8,9].
2. ConÞgure the BRG1. Write BRGC1 with 0x0001_035A. The DIV16 bit is not used
and the divider is 429 (decimal). The resulting BRG1 clock is 16
´ the preferred bit
rate.
3. Connect BRG1 to SMC1 using the CPM mux by clearing CMXSMR[SMC1,
SMC1CS].
4. In address 0x87FC, assign a pointer to the SMC1 parameter RAM.
5. Assuming one RxBD at the beginning of dual-port RAM followed by one TxBD,
write RBASE with 0x0000 and TBASE with 0x0008.
6. Write 0x1D01_0000 to CPCR to execute the INIT RX AND TX PARAMETERS
command.
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.
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 first 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 first 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.