Motorola MPC8260 - Manual (Page 936)

33-12 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
33.5.1 Receive/Transmit Function Code Registers (RFCR/TFCR)
Figure 33-9 shows the Þelds in the receive/transmit function code registers (RFCR/TFCR)
Table 33-6 describes the RFCR/TFCR Þelds.
33.6 SPI Commands
Table 33-7 lists transmit/receive commands sent to the CP command register (CPCR).
Bit 0 1 2 3 4 5 6 7
Field Ñ GBL BO TC2 DTB Ñ
Reset 0000_0000
R/W R/W
Addr SPI Base + 04 (RFCR)/SPI Base + 05 (TFCR)
Figure 33-9. RFCR/TFCRÑFunction Code Registers
Table 33-6. RFCR/TFCR Field Descriptions
Bits Name Description
0Р1 С Reserved, should be cleared.
2 GBL Global access bit
0 Disable memory snooping
0 Enable memory snooping
3Ð4 BO Byte ordering. Set BO to select the required byte ordering for the buffer. If BO is changed on-the-ßy, it
takes effect at the beginning of the next frame or BD.
00 True little-endian. Note this mode can only be used with 32-bit port size memory.
01 PowerPC little-endian.
1x Big-endian.
5 TC2 Transfer code 2. Contains the transfer code value of TC[2], used during this SDMA channel memory
access. TC[0Ð1] is driven with a 0b11 to identify this SDMA channel access as a DMA-type access.
6 DTB Data bus indicator.
0 Use 60x bus for SDMA operation.
1 Use local bus for SDMA operation.
7 Ñ Reserved, should be cleared.
Table 33-7. SPI Commands
Command Description
INIT TX
PARAMETERS
Initializes all transmit parameters in the parameter RAM to their reset state and should be issued only
when the transmitter is disabled. The
INIT TX AND RX PARAMETERS command can also be used to reset
both the Tx and Rx parameters.
CLOSE RXBD Forces the SPI controller to close the current RxBD and use the next BD for subsequently received data.
If the controller is not receiving data, no action is taken. Use this command to extract data from a
partially full buffer.