RL78/G1P
CHAPTER 11 SERIAL ARRAY UNIT
R01UH0895EJ0100 Rev.1.00
400
Nov 29, 2019
Multiple slaves can be connected to a master and communication can be performed by using the slave select input
function. The master outputs a slave select signal to the slave (one) that is the other party of communication, and each
slave judges whether it has been selected as the other party of communication and controls the SO pin output. When a
slave is selected, transmit data can be communicated from the SO pin to the master. When a slave is not selected, the
SO pin is set to high-impedance output. Therefore, short circuit of the SO pin with SO output of other slave can be
avoided. Furthermore, when a slave is not selected, no transmission/reception operation is performed even if a serial
clock is input from the master.
Caution Output the slave select signal by port manipulation.
Figure 11-75. Example of Slave Select Input Function Configuration
SAU
SAU
SCK
SSI
SI
SO
SAU
Master
Slave
Slave
Port
SCK
SSI
SI
SO
SCK
SSI
SI
SO
Caution Make sure that V
DD
≥
V
b
.
Select the N-ch open-drain output (V
DD
tolerance) mode for the SO00 pin.