Flash the GPNVM bits using Segger software (Atmel Cortex-M3)

FocusPaul · Nov 14th 2014, 11:20am

Hello!

I'm trying to find a way to change the GPNVM bits of the Atmel Cortex-M3 chip AT91SAM3X.

Is is possible to do this with J-Flash/J-Link Commander software? (using a J-Link Pro).

Thank you,
Paule

SEGGER - Alex · Nov 18th 2014, 11:36pm

Hi Paule,

In general, this is possible.
This can be done via a relatively simple sequence of memory commands.
Could you please let me know which GPNVM bit you want to modify?
I will then check, if we can provide some sample code short term.

- Alex

FocusPaul · Nov 20th 2014, 7:20am

Hello Alex,

I'd like to re-program _all_ GPNVM bits on SAM3X8E (please see ch. 9.3.1.10 in PDF description on atmel page: atmel.com/Images/doc11057.pdf).

If you would be so kind to give me an example on one of those bits, I'm sure I'll be able to use this example for other bits.

Thank you for your help,

Paule

SEGGER - Alex · Nov 20th 2014, 10:42am

Hi,

Via Commander:
Sample code for setting GPNVM bit 1 which is BMS => Boot from flash (1) or internal ROM (0)

C Source Code

// FlashRegFCR = 0x400E0A04;
// FlashRegFSR = 0x400E0A08;
// FlashRegFRR = 0x400E0A0C;
// Set GPNVM bit to "boot from flash" (0x5A << 24) | (GPNVMBitNo << 8) | (Cmd_SetGPNVMBit << 0)
w4 0x400E0A04, 0x5A00010B
// Wait until bit has been programmed
sleep 20

via J-Flash: Can be done by WriteU32 + Delay instructions in the Init / Exit steps that can be found at Options -> Project Settings -> CPU

If you need an optimized version which does not use fixed delays but reads the status etc.,
we recommend to get the J-Link SDK and write your own small application with it.

Best regards
Alex

C Source Code

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