Flash Read/Write

Browse source code on GitHub

Overview

This sample demonstrates using the flash API to perform basic erase, write and read operations on the internal flash of a device.

A single generic test function (flash_region_test) receives the flash device, byte offset, length and a region name, then runs the full erase/verify/write/read/verify cycle. The sample invokes it twice:

  1. PFM storage – the storage_partition in Program Flash (flash1).

  2. BFM top – the last page of Boot Flash Memory (flash0), exercising the upper address boundary.

All sizes (page size, write block size) are queried at runtime from the flash driver, so the sample works across different devices (e.g. PIC32CK, PIC32CZ) without modification.

Test steps

For each region the following five operations are performed:

  1. Erase one flash page

  2. Verify the erased region reads back as the erase value

  3. Write a test pattern

  4. Read back the written data

  5. Verify the data matches

Requirements

The board must have:

  • A flash controller with driver support in Zephyr

  • A storage_partition defined in the board devicetree

Building and Running

west build -b None samples/drivers/flash/flash_read_write
west flash

Flash Read/Write sample for pic32ck_sg01_cult
==========================

--- PFM storage test ---

PFM storage: flash device is ready.
PFM storage parameters:
  Write block size : 8 bytes
  Erase value      : 0xff
  Erase block size : 4096 bytes
  Page start offset: 0x1f8000
  Page index       : 508
  Total pages      : 512
  Test offset      : 0x1f8000
  Test size        : 4096 bytes

Test 1: PFM storage erase
  Erasing 4096 bytes at offset 0x1f8000 ...
  PFM storage erase succeeded!

Test 2: PFM storage erase verification
  PFM storage erase verification succeeded!

Test 3: PFM storage write
  Writing 4096 bytes (write block = 8 bytes) ...
  PFM storage write succeeded!

Test 4: PFM storage read
  Reading back 4096 bytes ...
  PFM storage read succeeded!

Test 5: PFM storage data verification
  PFM storage data read matches data written. Good!!

--- BFM top test ---

BFM top: flash device is ready.
BFM top parameters:
  Write block size : 8 bytes
  Erase value      : 0xff
  Erase block size : 4096 bytes
  Page start offset: 0x1f000
  Page index       : 31
  Total pages      : 32
  Test offset      : 0x1f000
  Test size        : 4096 bytes

Test 6: BFM top erase
  Erasing 4096 bytes at offset 0x1f000 ...
  BFM top erase succeeded!

Test 7: BFM top erase verification
  BFM top erase verification succeeded!

Test 8: BFM top write
  Writing 4096 bytes (write block = 8 bytes) ...
  BFM top write succeeded!

Test 9: BFM top read
  Reading back 4096 bytes ...
  BFM top read succeeded!

Test 10: BFM top data verification
  BFM top data read matches data written. Good!!

==========================
All flash tests PASSED.

See also

Flash