HD404639R Datasheet, PDF (83/135 Pages) Renesas Technology Corp – 4-Bit Single-Chip Microcomputer

Octal counter
(OC1, OC2)
SO₁ , SO₂
Idle control
logic
SCK₁ , SCK₂
I/O control
logic
Clock
SI₁ , SI ₂
1/2
1/2
HD404639R Series
Serial interrupt
request flag
(IFS1, IFS2)
Serial data
register (SR1L/U,
SR2L/U)
Transfer
control
Selector
System ^øPER
clock
Prescaler S (PSS)
3
Serial mode register
1A, 2A (SM1A,
SM2A)
Serial mode register
1B, 2B (SM1B,
SM2B)
Figure 66 Block Diagram of Serial Interface Serial Interface Operation
Serial Interface Operation
Selecting and Changing the Operating Mode: Tables 26 (A) and 26 (B) list the serial interfaces’
operating modes. To select an operating mode, use one of these combinations of port mode register A
(PMRA: $004), serial mode register 1A (SM1A: $005), and serial mode register 2A (SM2A: $01B)
settings; to change the operating mode of serial interface 1, always initialize the serial interface internally
by writing data to serial mode register 1A; and to change the operating mode of serial interface 2, always
initialize the serial interface internally by writing data to serial mode register 2A. Note that serial interface
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