topic MPC5675K - Software hanging on reading data flash sector in Other NXP Products

MPC5675K - Software hanging on reading data flash sector

mohammedshibin — Fri, 08 May 2015 13:13:09 GMT

Hai all,

My application is hanging while I am trying to read data flash sector 1(0x0080_4000) of MCU. All other sectors are working fine.

I have already performed around 10000 write cycle to sector 1. I am reading the sector using an 'unsigned long' pointer.

Please help me to identify the reason. Any help will be appreciated.

Thank you.

Re: MPC5675K - Software hanging on reading data flash sector

mohammedshibin — Mon, 11 May 2015 04:46:46 GMT

Hi,

Same code is working fine in another board. What could be the reason for hanging in the other board?

Re: MPC5675K - Software hanging on reading data flash sector

lukaszadrapa — Tue, 12 May 2015 11:54:35 GMT

Hi,

It is caused by ECC error, most likely. Each word in data flash memory has hidden 7bit ECC syndrome. The ECC mechanism provides correction of single-bit faults and reporting of multiple-bit errors.

ECC error can occur if:

- erase or program operation is terminated by unexpected reset, so the flash is left in undefined state

- if we programmed word in data flash that is not fully erased (different from 0xFFFFFFFF)

- if we performed too many erase/program cycles (flash wear-out)

In case of single-bit fault, the ECC circuitry automatically corrects the data. In case of multiple-bit error, the flash controller returns bus error and exception is triggered. Take a look at this document and examples for details:

https://community.freescale.com/docs/DOC-103300

The solution is to erase whole flash block. Then it can be programmed and read again.

Regards,

Lukas