Freescale Semiconductor FRDM-FXS-MULTI 데이터 시트
MISO
MOSI
SCLK
SPI_CS_B
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
R/W A6
A5
A4
A3
A2
A1 A0
17
18
19
20
21
22
23
24
D7 D6 D5 D4 D3 D2
D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
Figure 11. SPI multiple read operation showing 2 bytes written
3.2.3 SPI 3-Wire Mode
The FXAS21000 can be configured to operate in 3-wire mode. In this mode the only
signal pins used are SPI_CS_B, SCLK, and SPI_DIO; the MISO pin is not used. 3-
wire mode is selected by setting the SPIW bit in CTRL_REG0.
signal pins used are SPI_CS_B, SCLK, and SPI_DIO; the MISO pin is not used. 3-
wire mode is selected by setting the SPIW bit in CTRL_REG0.
Read operations in 3-Wire mode are different from read operations in 4-Wire mode.
• At the end of the address cycle of read operations in 3-Wire mode, the MOSI pin
switches from SI to SO
• Multiple read operations in 3-wire mode use auto-increment
• Multiple read operations in 3-wire mode return data on the MOSI pin
• Multiple read operations in 3-wire mode return data on the MOSI pin
MISO
SPI_DIO
SCLK
SPI_CS_B
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
R/W A6
A5
A4
A3
A2
A1 A0 D7 D6 D5 D4 D3 D2
D1 D0
Figure 12. SPI 3-Wire single read operation
Write operations in 3-wire mode are identical to write operation in 4-wire mode since
the MISO pin is not used in either mode of operation.
the MISO pin is not used in either mode of operation.
Digital Interfaces
Xtrinsic 3-Axis Digital Angular Rate Gyroscope, Rev1.2, 7/2014.
19
Freescale Semiconductor, Inc.