Motorola MPC8260 User Manual

33-12

MOTOROLA

Figure 33-9 shows the Þelds in the receive/transmit function code registers (RFCR/TFCR)

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

Ñ

Reset

0000_0000

R/W

R/W

Addr

SPI Base + 04 (RFCR)/SPI Base + 05 (TFCR)

0Ð1

Reserved, should be cleared.

2

Global access bit
0 Disable memory snooping
0 Enable memory snooping

3Ð4

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

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

Data bus indicator.
0 Use 60x bus for SDMA operation.
1 Use local bus for SDMA operation. 

7

Reserved, should be cleared.

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.