
HD404849 Series
90
Bit
Initial value
Read/Write
Bit name
3
Undefined
R/W
SR7
2
Undefined
R/W
SR6
0
Undefined
R/W
SR4
1
Undefined
R/W
SR5
Serial data register (upper digit) (SRU: $007)
Figure 73 Serial Data Register (SRU)
LSB
MSB
1
2
3
4
5
6
7
8
Transmit clock
Serial output
data
Serial input data
latch timing
Figure 74 Serial Interface Input/Output Timing
Port Mode Register A (PMRA: $004):
This register has the following functions (figure 75).
R2
2
/SI pin function selection
R2
3
/SO pin function selection
Port mode register A (PMRA: $004) is a 2-bit write-only register, and is reset to $0 by MCU reset.
Bit
Initial value
Read/Write
Bit name
3
—
—
Not used
2
—
—
Not used
0
0
W
PMRA0
1
0
W
PMRA1
PMRA0
0
1
R2
3
/SO mode selection
R2
3
SO
Port mode register A (PMRA: $004)
PMRA1
0
1
R2
2
/SI mode selection
R2
2
SI
Figure 75 Port Mode Register A (PMRA)