CHAPTER 13 SERIAL INTERFACE CHANNEL 0
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User’s Manual U11302EJ4V0UM
(3) Signals
Figure 13-7 shows the RELT and CMDT operations.
Figure 13-7. RELT and CMDT Operations
(4) MSB/LSB switching as the start bit
In the 3-wire serial I/O mode, transfer can be selected to start from the MSB or LSB.
Figure 13-8 shows the configuration of serial I/O shift register 0 (SIO0) and the internal bus. As shown
in the figure, the MSB/LSB can be read/written in reverse form.
MSB/LSB switching as the start bit can be specified using bit 2 (CSIM02) of serial operating mode register
0 (CSIM0).
Figure 13-8. Circuit for Switching Transfer Bit Order
Start bit switching is realized by switching the bit order for data write to SIO0. The SIO0 shift order remains
unchanged.
Thus, switch the MSB/LSB start bit before writing data to the shift register.
RELT
CMDT
SO0 latch
7
6
Internal bus
1
0
LSB start
MSB start
Read/write gate
SI0
Shift register 0 (SIO0)
Read/write gate
SO0
SCK0
D
Q
SO0 latch
Содержание mPD780204
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