M38027E8SP Datasheet, PDF (22/51 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
3802 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
Serial I/O2
The serial I/O2 function can be used only for clock synchronous
serial I/O.
For clock synchronous serial I/O the transmitter and the receiver
must use the same clock. If the internal clock is used, transfer is
started by a write signal to the serial I/O2 register.
Serial I/O2 control register (SIO2CON) 001D16
The serial I/O2 control register contains seven bits which control
various serial I/O functions.
b7
b0
Serial I/O2 control register
(SIO2CON : address 001D16)
Internal synchronous clock selection bits
b2 b1 b0
0 0 0: f(XIN)/8
0 0 1: f(XIN)/16
0 1 0: f(XIN)/32
0 1 1: f(XIN)/64
1 1 0: f(XIN)/128
1 1 1: f(XIN)/256
Serial I/O2 port selection bit (SM23)
0: I/O port
1: SOUT2,SCLK2 output pin
SRDY2 output enable bit (SM24)
0: I/O port
1: SRDY2 output pin
Transfer direction selection bit (SM25)
0: LSB first
1: MSB first
Serial I/O2 synchronous clock selection bit (SM26)
0: External clock
1: Internal clock
P51/SOUT2 P-channel output disable bit
0: CMOS output (in output mode)
1: N-channel open-drain output (in output mode)
Fig. 15 Structure of serial I/O2 control register
1/8
Internal synchronous
clock selection bits
1/16
Data bus
1/32
XIN
1/64
1/128
1/256
P53/SRDY2
P53 latch
Serial I/O2 synchronous
"0"
clock selection bit
SRDY2
"1"
Synchronization circuit
SRDY2 output enable bit
"1"
"0"
External clock
P52/SCLK2
P51/SOUT2
P50/SIN2
P52 latch
"0"
"1"
Serial I/O2 port selection bit
P51 latch
"0"
"1"
Serial I/O2 port selection bit
Serial I/O counter 2 (3)
Serial I/O2
interrupt request
Serial I/O shift register 2 (8)
Fig. 16 Block diagram of serial I/O2 function
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