2-wire UART Serial Programming with RFP on RL78/G23

Question

RFP shows that a COM port and 2-wire UART can be used to program a target RL78/G23. It also allows configuring a reset signal from one of the control lines (DTR/RTS)

According to documentation I've read, including "RL78 Microcontroller (RL78 Protocol C) Serial Programming Guide" R01AN5756EJ0100, TOOL0 is essential to enter programming mode.

Am I misunderstanding the RFP in that it can program a target MCU using two wire communications?

Thanks.

AZ_Renesas · Accepted Answer

As listed RFP supports 2-wire dedicated UART with TypeD connection settings:

For examples of recommended connections of type D, refer to the RL78 Debugging functions Using Serial port Application notes

However, I see no reason to prefer 2-wire UART over single wire UART for RFP connection. With a 2-wire connection you will just use 1 more pin for the same baud rate.

JimB · Answer

TOOL0 needs to be controlled by the programmer to set the mode. Connect TOOL0 to the incoming TxD via a serial resistor. The G23 Fast ProtoBoard is a suitable reference design (and is very low-cost). 
 
 There is sample code to use a Raspberry Pi to program RL78/G23:

Sample Code 
 
 Flash programmer with Raspberry Pi (RL78 Protocol C) - Sample Code 
 ZIP 1.29 MB Feb 28, 2024

AZ_Renesas · Answer

Hello, 
 RFP can support serial programming using 2-wire UART if the dedicated UART pins TOOLTxD and TOOLRxD are used:

2-wire UART Serial Programming with RFP on RL78/G23

Top Replies