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Best method to erase code flash memory? #148

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chanqueo opened this issue Nov 8, 2022 · 6 comments
Open

Best method to erase code flash memory? #148

chanqueo opened this issue Nov 8, 2022 · 6 comments

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@chanqueo
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chanqueo commented Nov 8, 2022 •
edited

Hi,
On my device, flash memory is from 0x00000000 to 0x1fffffff.
Flash allocated to source code is only from 0x00000000 to 0x00100000.
erase() method will erase the whole flash memory.
What it the best method to only clear flash dedicated to source code?

Here is the source code I am using.
flash_address, flash_size = self.get_radio_board_flash_info()
data = [0xFF] * flash_size
self.jlink.flash_bytes(data, flash_address)
@hkpeprah
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Hm. I'm not sure what the best way is. What happens if you try the aforementioned?

@chanqueo
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chanqueo commented Nov 21, 2022 •
edited

As you know, when a flash is erased, all the bits are set to 1.
So writing 0xFF everywhere gives the same result as erase operation.
self.get_radio_board_flash_info() returns the start address and size of the flash dedicated to source code.
After running my source code, the flash contents is erased as expected but the execution takes very long.

  1. compare
  2. clear
  3. write

Instead of one erase operation.
I'm surprised to be the only one concerned.

@hkpeprah
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Looks like #154 is related to this.

@chanqueo
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I'm not sure.
My question is, what is the best way to erase only part of the flash memory?
The jlink.erase() method will erase the whole flash memory, and this is not what I want, because of bootloader...

denravonska added a commit to denravonska/pylink that referenced this issue Nov 25, 2022
@denravonska
Switch to read-write-modify flashing.
8cc7759 
This enables programming the chip without having to erase the entire contents.
Instead, JLink will erase where needed while retaining the data that's within
the same sectors but outside of the specified write area.

Closes square#154, square#148
denravonska added a commit to denravonska/pylink that referenced this issue Nov 25, 2022
@denravonska
Switch to read-write-modify flashing.
cceaf88 
This enables programming the chip without having to erase the entire contents.
Instead, JLink will erase where needed while retaining the data that's within
the same sectors but outside of the specified write area.

Closes square#154, square#148
@denravonska denravonska mentioned this issue Nov 25, 2022
Merged
denravonska added a commit to denravonska/pylink that referenced this issue Nov 25, 2022
@denravonska
Switch to read-write-modify flashing.
61b024a 
This enables programming the chip without having to erase the entire contents.
Instead, JLink will erase where needed while retaining the data that's within
the same sectors but outside of the specified write area.

Closes square#154, square#148
denravonska added a commit to denravonska/pylink that referenced this issue Nov 25, 2022
@denravonska
Switch to read-modify-write flashing.
1147466 
This enables programming the chip without having to erase the entire contents.
Instead, JLink will erase where needed while retaining the data that's within
the same sectors but outside of the specified write area.

Closes square#154, square#148
@denravonska
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@chanqueo #155 should fix this. It causes flash to only erase the target area, leaving the bootloader (and other permanent data) untouched.

Also, apologies for opening a duplicate issue. I should've checked beforehand.

hkpeprah pushed a commit to denravonska/pylink that referenced this issue Dec 5, 2022
@denravonska @hkpeprah
Switch to read-modify-write flashing.
f17199d 
This enables programming the chip without having to erase the entire contents.
Instead, JLink will erase where needed while retaining the data that's within
the same sectors but outside of the specified write area.

Closes square#154, square#148
@hkpeprah
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hkpeprah commented Dec 8, 2022

Remedy should be available in v1.0.0 thanks to @denravonska.

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3 participants
@denravonska @hkpeprah @chanqueo