Serial Periph eral Inter face (SPI)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
38-6 Freescale Semiconductor

mode. Gaps should be inserted between multiple characters to keep from exceeding the maximum

sustained data rate.

38.4 Programming the SPI Registers

The following sections describe the registers used in configuring and operating the SPI.

38.4.1 SPI Mode Re gister (SPMODE)

The SPI mode register (SPMODE), shown in Figure 38-4, controls both the SPI operation mode and clock

source.

Table38-1 describes the SPMODE fields.

0 1 2 3 4 5 6 7 8 9 101112131415
Field — LOOP CI CP DIV16 REV M/S EN LEN PM
Reset 0000_00 — 0_0000_0000
R/W R/W
Addr 0x0x11AA0
Figure 38-4. SPMODE—SPI Mode Register
Table38-1. SPMODE Field Descriptions
Bits Name Description
0 Reserved, should be cleared.
1LOOP Loop mode. Enables local loopback operation.
0 Normal operation.
1 Loopback mode. The transmitter output is internally connected to the receiver input. The receiver
and transmitter operate normally, except that received data is ignored.
2CI Clock invert. Inver ts SPI clock po larity. See Figure 38-5 and Figure 38-6.
0 The inactive state of SPICLK is low.
1 The inactive state of SPICLK is high.
3CP Clock phase. Selects the transfer format. See Figure38-5 and Figure 38-6.
0 SPICLK starts toggling at the middle of the data transfer.
1 SPICLK starts toggling at the beginning of the data transfer.
4DIV16 Divide by 16. Selects the clock source for the SPI baud rate generator when configured as an SPI
master. In slave mode, SPICLK is the clock source.
0 BRGCLK is the input to the SPI BRG.
1 BRGCLK/16 is the input to the SPI BRG.
5REV Reverse data. Determines the receive and transmit character bit order.
0 Reverse data—lsb of the character sent and received first.
1 Normal operation—msb of the character sent and received first.
6M/S Master/slave. Selects master or slave mode.
0 The SPI is a slave.
1 The SPI is a master.