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"In debugging RX MCU, do the RxD1 and TxD1 pins have to be connected? "

Latest Updated:10/24/2014

Question:

I am considering debugging of an RX family MCU using the E1 or E20 emulator via the FINE connection. During debugging, do the RxD1 and TxD1 pins have to be connected?

Answer:

When debugging is performed via the FINE connection, the RxD1 and TxD1 pins are not used. Therefore, when performing only debugging using the E1 or E20 emulator, the RxD1 and TxD1 pins need not be connected to the E1 or E20 emulator.

Note however when performing on-board FLASH programming (*1) in boot mode, the RxD1 and TxD1 pins must be connected (*2) to the connectors of the E1 or E20 emulator.

*1 Programming flash memory via the E1 or E20 emulator using the Flash Development Toolkit or Renesas Flash Programmer

*2 In RX200 and RX100 series MCUs, flash memory can be also programmed through the FINE connection without using the RxD1 and TxD1 pins. In this case, the RxD1 and TxD1 pins need not be connected to the E1 or E20 emulator.

When performing debugging with the FINE connection, since the E1 or E20 emulator does not control the RxD1 and TxD1 pins, the output from the E1 or E20 emulator is high-impedance (Hiz).
On the other hand, when performing on-board FLASH programming in boot mode, since the E1 or E20 emulator does control the RxD1 and TxD1 pins, a switch should be attached so that the output from the E1 or E20 emulator does not collide with the output from the user system.

Product sites:
- Flash Development Toolkit
- Renesas Flash Programmer

Since the RxD1 and TxD1 functions are assigned to multiple pins in some microcontrollers, through the hardware manual, confirm to which pins the RxD1 and TxD1 functions used in boot mode are assigned.

Suitable Products
E1 [R0E000010KCE00]
E20 [R0E000200KCT00]
Renesas Flash Programmer
Flash Development Toolkit