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The GR-PEACH is an mbed platform with an RZ/A1H and a single QSPI Flash device. While it was intended to be used with the mbed cloud development environment, the board itself can be loaded with Linux, and particularly XIP Linux (since you only have the 10MB of RAM inside the RZ/A1H).

In order to program the board, or to enlarge its flash disk size some hardware modifications are required.

Board Modifications

SPI Flash

  • The GR-PEACH only comes with a 8MB QSPI flash. That is pretty small for Linux, especially XIP Linux. It is recommended that you replace it with a the 16MB version of the same Macronix chip. Because the package footprint is a 8-SOP, your choices on drop in SPI flash replacements are pretty small. This is the recomended device to use:
Macronix Part Number: MX25L12835FM2I-10G
Digi-Key Part Number: 1092-1197-ND (http://www.digikey.com/products/en?keywords=1092-1197-ND)

There is a 32MB version QSPI flash version (Macronix MX25L25645G), but it is hard to get unless you order 4,000 at a time.


  • Since the GR-PEACH was intended to be used for mbed, the SPI flash was meant to be loaded using the 'mbed file drag and drop' method. It is much easier to just use the JTAG interface with a Segger Jlink (or the JLINK-LITE that comes with the Renesas RSK kit). To do this, you need to solder on the 9-pin JTAG connector (yes, it's called a mini Cortex M connector...but it's the same signals)
Samtec FTSH-105-01-L-D-K
  • Note that you must remove one of the pins on the 10-pin connector by either cutting it or pulling it out with pliers before you solder it down. The reason is that the Cortex-M adapter expects there NOT to be a pin there (and they block it on the plug). If a pin is there, the connector will not plug in.
See image: Grpeach jtag header.jpg
  • You will also need an adapter to convert the full 20-pin JTAG interface to the mini connector.
  • Note that we will still use the mbed USB connection (the one closest to the corner) for board power and serial console.

Update mbed Firmware

It is recommended that you update your GR-PEACH firmware to whatever the last version is (just to fix any USB-Serial bugs)

  • NOTE The 'drag&drop' firmware update has sometimes proved to fail, causing the board to always enter the in-famous 'CRP_DISABLD' state as if JP2 is always shorted even after the first firmware update. If that happens, just dd the new firmware image to its designed destination.
dd if=grpeach_8mb_20161212.bin of=/media/CRP\ DISABLD/firmware.bin conv=notrunc

mbed USB-to-Serial Driver

  • If you will be using Windows for your serial terminal, you will need to download the mbed drivers from here
  • If you will be using Linux for your serial terminal, they should already be included as part of your distribution and serial link will appear as /dev/ttyACM0
  • Note that we will be using a baud rate of 115200bps(8 bits, 1 stop bit, no parity)

Running Linux

Please refer to: