Motorola MC68VZ328 Manuale Utente
SPI 2 Overview
Serial Peripheral Interface 1 and 2
13-11
SPISPC
SPI 1 Sample Period Control Register
0x(FF)FFF70A
13.4
SPI 2 Overview
This section discusses how SPI 2 can be used to communicate with external devices, such as EEPROMs,
analog-to-digital converters, and other peripherals. The SPI 2 module is a 3- or 4-wire system, depending
on whether you are using unidirectional or bidirectional communication mode. It provides the clock for
data transfer and can only function as a master device. It is fully compatible with the serial peripheral
interface on Motorola’s 68HC05 and 68HC11 microprocessors. Figure 13-3 shows the SPI 2 block
diagram.
analog-to-digital converters, and other peripherals. The SPI 2 module is a 3- or 4-wire system, depending
on whether you are using unidirectional or bidirectional communication mode. It provides the clock for
data transfer and can only function as a master device. It is fully compatible with the serial peripheral
interface on Motorola’s 68HC05 and 68HC11 microprocessors. Figure 13-3 shows the SPI 2 block
diagram.
Figure 13-3. SPI 2 Block Diagram
BIT 15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
BIT 0
CSRC
WAIT
TYPE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0x0000
Table 13-6. SPI 1 Sample Period Control Register Description
Name
Description
Setting
CSRC
Bit 15
Bit 15
Counter Clock Source—This bit selects the
clock source for the sample period counter.
clock source for the sample period counter.
0 = SPICLK1 clock
1 = CLK32 (32.68 kHz normal crystal used)
1 = CLK32 (32.68 kHz normal crystal used)
WAIT
Bits 14–0
Bits 14–0
Wait—Number of clock periods inserted
between data transactions in master mode
between data transactions in master mode
0000 = 0 clocks
0001 = 1 clock
0002 = 2 clocks
.
.
.
7FFF = 32767 clocks (approximately 1 second)
0001 = 1 clock
0002 = 2 clocks
.
.
.
7FFF = 32767 clocks (approximately 1 second)
SPICLK2
Control
MPU Interface
SPIRXD
SPITXD
MSB
Clock
Generator
Shift Register