NEC PD78F9488 User Manual

Page 231

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CHAPTER 12 SERIAL INTERFACE 1A0

User’s Manual U15331EJ4V1UD

231

Symbol

<7> 6 <5>

<4> 3 2 1 0

Address

After

reset

R/W

CSIM1A0 CSIE10 DIR10 ATE0 LSCK10

0

0

SCL101 SCL100 FF78H

00H

R/W

Specification of operation enable/disable

CSIE10

Shift register operation

Serial counter

Port

Note

0

Operation stopped

Cleared

Port function

1

Operation enabled

Count operation enabled

Serial function + port function

DIR10

Specification of first bit of serial transfer data

0 MSB

1 LSB

ATE0

Selection of operation mode

0

3-wire serial mode

1

3-wire serial mode with automatic transmit/receive function

LSCK10

Chip enable control of SCK10 pin

0

SCK10 is used as port (P23) when CSIE10 = 0.
SCK10 is used for clock output when CSIE10 = 1.

1

SCK10 is fixed to high-level output when CSIE10 = 0.
SCK10 is used for clock output when CSIE10 = 1.

SCL101 SCL100

Selection of serial clock

0

0

External clock input to SCK10 pin

0 1

f

X

/2

2

(1.25 MHz)

1 0

f

X

/2

3

(625 kHz)

1 1

f

X

/2

4

(313 kHz)


Note When CSIE10 = 0 (SIO1A0 operation stop status), the SCK10/P23, SO10/P24, and SI10/P25 pins can

freely be used as port pins. Also, when CSIE10 is used for transmission only, the SI10/P25 pin can be
used as P25 (CMOS I/O) (set bit 7 (RE0) of ADTC0 to 0).


Remarks 1. f

X

: Main system clock oscillation frequency

2. The parenthesized values apply to operation at f

X

= 5.0 MHz.

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