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Renesas Singapore - Knowledgebase

How is the checksum value calculated in the E8a/E8 Program Flash (*) mode?

Last Updated:04/26/2017


How is the checksum value calculated in the Program Flash (*) mode?
* This mode name is displayed as [Writing Flash Memory] on an earlier version than the E8 emulator software V.2.09 Release 00.


The checksum displayed when a program is downloaded to the flash memory in the E8a/E8 Program Flash mode is calculated as follows:

The entire flash memory area of the MCU (internal RAM and non-flash memory reserved areas are not included in the calculation) is calculated in byte units and displayed in 4 bytes.

When E8a/E8 is connected in the Program Flash mode, all flash memory areas are cleared. Therefore, at the time of download, the initial value of the Flash memory areas in which data is not assigned will be 0xff.

Ex:    R8C Family:
The flash memory area of the R8C/25 consists of a data area and a program area.In the Program Flash mode, the data of both areas is calculated in bytes and displayed as a 4-byte checksum value.
Ex:    H8/Tiny Series:
The calculation area for H8/3664F is from H'0000 to H'7FFF. However, for MCUs that have an E8a/E8-dedicated ROM area, that area is also included in the calculation. For example, in H8/3672F, the calculation area is from H'0000 to H'4FFF.
Note that addresses for dedicated ROM areas are not always provided in the hardware manual (H8/36049F, for example). In this case, you will need to refer to the Additional Document for E8a/E8 Users Manual corresponding to you are using.

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