UPD784938 Datasheet, PDF (443/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 18 ASYNCHRONOUS SERIAL INTERFACE/3-WIRE SERIAL I/O
18.3.2 Clocked serial interface mode registers (CSIM1, CSIM2)
CSIM1 and CSIM2 are 8-bit registers that specify operations in the 3-wire serial I/O mode.
These registers can be read or written to with an 8-bit manipulation instruction or bit manipulation instruction. The CSIM1
and CSIM2 format is shown in Figure 18-11.
RESET input clears these registers to 00H.
Figure 18-11. Format of Clocked Serial Interface Mode Register 1 (CSIM1) and Clocked Serial Interface
Mode Register 2 (CSIM2)
7
6
5
4
3
2
1
0 Address After reset R/W
CSIM1 CTXE1 CRXE1 0
0
0 DIR1 CSCK1 0 0FF84H
00H
R/W
CSIM2 CTXE2 CRXE2 0
0
0 DIR2 CSCK2 0 0FF85H
00H
R/W
(n = 1, 2)
CSCKn
Serial Clock Selection Bit
Source Clock
In case of SCKn
(CTXEn, CRXEn = 1)
0 External input Input
clock to SCKn pin
1 Baud rate
CMOS output
generator output
DIRn
Operation Mode Specification
(Transfer Bit Order)
0 MSB-first
1 LSB-first
CTXEn CRXEn Transmit/Receive Operation
0
0 Transmission/reception disabled,
or asynchronous serial interface
mode
0
1 Reception enabled
1
0 Transmission enabled
1
1 Transmission/reception enabled
Preliminary User’s Manual U13987EJ1V0UM00
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