topic Re: Flash write stalls in i.MX RT Crossover MCUs

Flash write stalls

Robert123 — Mon, 16 Aug 2021 11:43:09 GMT

Hi, I am writing an application which downloads a new image (over-the-air update) from a HTTP server.

The size of the new image is a bit larger than 400 kbytes. After approximately 100-200 kbytes the write to the flash memory fails/stalls. I cannot get any useful information from the debugger.

I disable the interrupts and enable between each write to the flash as shown below:

unsigned char https_buf[1024]; int read_request() { do { len = sizeof(https_buf); memset(https_buf, 0, sizeof(https_buf)); ret = lwip_recv(tlsDataParams.fd, https_buf, len, 0); if (ret == 0) { PRINTF("\n\nEOF\r\n"); goto exit; } uint32_t regPrimask = DisableGlobalIRQ(); result = mflash_drv_write(chunk_addr, (uint8_t*)https_buf, len); EnableGlobalIRQ(regPrimask); } while (1);

I am using a Embedded Artists imx-rt1062-developers-kit with the following SDK: eaimxrt1062_sdk_2.9.3_freertos. The flash memory is a Adesto XIP.

Could you give any hints on why the write to flash stalls?

Re: Flash write stalls

Robert123 — Mon, 16 Aug 2021 11:41:52 GMT

Found a solution by ereasing the sector before writing to it, as described here: https://community.nxp.com/t5/NXP-Designs/Flash-Write-with-FreeRTos/m-p/1134245

result = mflash_drv_sector_erase(chunk_addr); if (result != 0) { PRINTF("\r\nCould not earase sector\r\n"); } result = mflash_drv_write(chunk_addr, (uint8_t*)&https_buf[start_image_pos], len - start_image_pos); if (result != 0) { PRINTF("\r\nError during write\r\n"); }

Re: Flash write stalls

Robert123 — Wed, 18 Aug 2021 06:20:48 GMT

double post

Re: Flash write stalls

Robert123 — Wed, 18 Aug 2021 06:19:58 GMT

Actually, the problem still exists when I continued to work on my project today. I have tried to read and erase the flash memory before writing and also tried to reset the flex SPI but nothing works. The write to flash write still stalls/crashes.

Re: Flash write stalls

Alexis_A — Fri, 20 Aug 2021 21:14:36 GMT

Hello @Robert123,

Is this a problem with writing at a certain sector? If you write at the sector that is stalling the operation does the same behavior is present?

Best Regards,
Alexis Andalon

Re: Flash write stalls

Robert123 — Mon, 23 Aug 2021 08:27:32 GMT

It stalls at different sectors from 100 to 300 kbytes (one sector is 10 kbyte). I am running FreeRTOS (for the lwip stack) and I think it may interfere when I am disabling the interrupts while I am writing to flash. Sometimes I am unable to fetch the entire binary and lwip_recv returns 0 indicating "end of file" premature.

I solved the OTA update by copying the entire binary to a temporary buffer. But the buffer is quite large so it would be nice to allow writing to flash while still enabling interrupts.

Re: Flash write stalls

Alexis_A — Mon, 23 Aug 2021 23:13:10 GMT

Hello @Robert123,

I think to ensure the communication in the ethernet side your workaround would be the best option.

Best Regards,

Alexis Andalon

Re: Flash write stalls

Robert123 — Fri, 27 Aug 2021 11:40:07 GMT

Thanks, do you think a solution would be to replace lwip with the freertos TCP/IP stack? https://www.freertos.org/FreeRTOS_Support_Forum_Archive/November_2014/freertos_FreeRTOS_TCP_IP_stack_vs_lwIP_8324ceabj.html

It would be nice to avoid allocating a large buffer in RAM and write directly to flash.