Technical information
2-36
3800 GROUP USER’S MANUAL
APPLICATION
2.3 Serial I/O
(2) Output of serial data (control of a peripheral IC)
Outline : 4-byte data is transmitted and received through the clock synchronous serial I/O. The CS
signal is output to a peripheral IC through the port P5
3.
Fig. 2.3.19 Connection diagram [Output of serial data]
Specifications : • The Serial I/O is used. (clock synchronous serial I/O is selected)
• Synchronous clock frequency : 125 kHz (f(X
IN) = 4 MHz is divided by 32)
• Transfer direction : LSB first
• The
Serial I/O1 interrupt is not used.
• The Port P53 is connected to the CS pin (“L” active) of the peripheral IC for a
transmission control (the output level of the port P5
3 is controlled by software).
Figre 2.3.20 shows an output timing chart of serial data.
Fig. 2.3.20 Timing chart [Output of serial data]
P53
SCLK
TXD
CS
Peripheral IC3800 group
DATA
CS
CLK
CLK
DATA
CS
DO
0
DO
1
DO
2
DO
3
CLK
DATA