HD404639R Datasheet, PDF (96/135 Pages) Renesas Technology Corp – 4-Bit Single-Chip Microcomputer

HD404639R Series
Miscellaneous register (MIS: $00C)
Bit
Initial value
Read/Write
Bit name
3
0
W
MIS3
2
0
W
MIS2
1
0
W
MIS1
0
0
W
MIS0
MIS1
0
MIS0
0
1
1
0
1
t_RC
0.12207 ms
0.24414 ms*
7.8125 ms
31.25 ms
Not used
MIS2
0
1
R4₃/SO₁ PMOS on/off selection
On
Off
MIS3
0
1
Pull-up MOS on/off selection
Off
On
Note: * This value is valid only for direct transfer operation.
Figure 76 Miscellaneous Register (MIS)
Serial Mode Register 2A (SM2A: $01B): This register has the following functions (figure 77).
• R5₁/SCK₂ pin function selection
• Serial interface 2 transmit clock selection
• Serial interface 2 prescaler division ratio selection
• Serial interface 2 initialization
Serial mode register 2A (SM2A: $01B) is a 4-bit write-only register. It is reset to $0 by MCU reset.
A write signal input to serial mode register 2A discontinues the input of the transmit clock to serial data
register 2 (SR2L: $01D, SR2U: $01E) and the octal counter, and the octal counter is reset to 000.
Therefore, if a write is performed during data transfer, the serial 2 interrupt request flag (IFS2: $023, bit 2)
is set.
Written data is valid from the second instruction execution cycle after the write operation, so the SM2A
read instruction must be executed at least two cycles after that.
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