MOTOROLA
Chapter 31. Serial Peripheral Interface
31-7
Part V. The Communications Processor Module
31.4 SPI Registers
The following sections describe the registers used in conÞguring and operating the SPI.
31.4.1 SPI Mode Register (SPMODE)
The SPI mode register (SPMODE), shown in Figure 31-4, controls both the SPI operation
mode and clock source.
Table 31-1 describes the SPMODE Þelds.
Bit
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Field
Ñ
LOOP
CI
CP
DIV16
REV
M/S
EN
LEN
PM
Reset
0000_00
Ñ
0_0000_0000
R/W
R/W
Addr
0xAA0
Figure 31-4. SPI Mode Register (SPMODE)
Table 31-1. SPMODE Field Descriptions
Bits
Name
Description
0
Ñ
Reserved, should be cleared.
1
LOOP 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.
2
CI
Clock invert. Inverts SPI clock polarity. See Figure 31-5 and Figure 31-6.
0 The inactive state of SPICLK is low.
1 The inactive state of SPICLK is high.
3
CP
Clock phase. Selects the transfer format. See Figure 31-5 and Figure 31-6.
0 SPICLK starts toggling at the middle of the data transfer.
1 SPICLK starts toggling at the beginning of the data transfer.
4
DIV16 Divide by 16. Selects the clock source for the SPI baud rate generator when conÞgured 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.
5
REV
Reverse data. Determines the receive and transmit character bit order.
0 Reverse dataÑlsb of the character sent and received Þrst.
1 Normal operationÑmsb of the character sent and received Þrst.
6
M/S
Master/slave. Selects master or slave mode.
0 The SPI is a slave.
1 The SPI is a master.
Note that master/slave mode is undeÞned at reset.
7
EN
Enable SPI. Do not change other SPMODE bits when EN is set.
0 The SPI is disabled. The SPI is in a reset state and consumes minimal power. The SPI BRG is not
functioning and the input clock is disabled.
1 The SPI is enabled.
Summary of Contents for MPC860 PowerQUICC
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Page 78: ...I iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
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Page 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
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Page 325: ...MOTOROLA Part IV Hardware Interface IV v Part IV Hardware Interface ...
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Page 998: ...37 48 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part VI Debug and Test ...
Page 1016: ...A 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
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