RL78/G15 CHAPTER 19 FLASH MEMORY
R01UH0959EJ0110 Rev.1.10 Page 661 of 765
Mar 7, 2023
19.2.2 Communication mode
Communication between the external device and the RL78 microcontroller is established by serial communication using
the TOOL0 pin via the dedicated UART of the RL78 microcontroller.
Transfer rate: Fixed to 115200 bps
Figure 19-4. Communication with External Device
V
SS
V
DD
RL78 microcontroller
V
DD
GND
RESET_OUT
TxD
RxD
TOOLTxD
TOOLRxD
PORT
TOOL0
External device
(such as microcontroller and ASIC)
______
RESET
The external device generates the following signals for the RL78 microcontroller.
Table 19-4. Pin Connection
External Device RL78 microcontroller
Signal Name I/O Pin Function Pin Name
V
DD
I/O
V
DD
voltage generation/
power monitoring
V
DD
GND — Ground V
SS
RESET_OUT Output Reset signal output RESET
¯¯¯¯¯¯
RxD Input Receive signal TOOLTxD
TxD Output Transmit signal TOOLRxD
PORT Output Mode signal TOOL0