HD404344R Datasheet, PDF (72/102 Pages) Renesas Technology Corp – 4-bit microcomputer has an A/D converter

HD404344R Series/HD404394 Series
Serial Data Register (SRL: $006, and SRU: $007): This register has the following functions (figures 47
and 48):
• Transmission data write and shift
• Receive data shift and read
Data written to the serial data registers is output from the SO pin, LSB first, synchronously with the falling
edge of the transmit clock.
Also, data from the SI pin (from the LSB) is input synchronously with the rising edge of the transmit clock.
Reading or writing to the serial data register should be performed after data transfer. Read/write operation
to this register during data transfer does not guarantee valid data. The input/output timing chart for the
transmit clock and the data are shown in figure 49.
Serial data register (lower) (SRL: $006)
Bit
Initial value
Read/Write
Bit name
3
2
1
0
Undefined Undefined Undefined Undefined
R/W R/W R/W R/W
SR3 SR2 SR1 SR0
Figure 47 Serial Data Register (SRL)
Serial data register (upper) (SRU: $007)
Bit
Initial value
Read/Write
Bit name
3
2
1
0
Undefined Undefined Undefined Undefined
R/W R/W R/W R/W
SR7 SR6 SR5 SR4
Figure 48 Serial Data Register (SRU)
Ttransmit clock
Serial output
data
Serial input
data latch
timing
1
2
3
4
5
6
7
8
LSB
MSB
Figure 49 Serial Interface Timing
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