Hi Everyone, Weare working on a project where using SPI3 with DMA to communicate with flash. The problem we are facing is when copying a file from our module to PC, (file size is around 130 MB), it takes almost 14 minutes to complete the transfer.

[SNata.1]

Is there anyway we can decrease this time. We are using void DMA2_Channel2_IRQHandler(void) and void DMA2_Channel1_IRQHandler(void). Both RX and Tx callbacks are not firing and really not able to debug this issue. Looking forward to a solution. Thanks everyone.

[Uwe Bonnes]

How is the transfer from board to PC done (e.g. Serial, USB FS, USB HS)? What device?

[SNata.1]

HI, Thanks for the quick reply. It is USB HS. STM32L151VEYx MCU. Device is a datalogger board, designed and fabricated by us.

[Tesla DeLorean]

Depends where the bottleneck is. USB MSC probably looking at 4-5 minutes​

[Tesla DeLorean]

I'd imagine it could be done faster.

Post a bit light​ on any usable detail to provide a diagnosis.

Why can't you and your team better understand and debug the failure?

​

I​nterrupts and callbacks not occurring suggests an error is being flagged or the transfer is not actually happening. Or you're using C++. Do an inspection of the peripheral registers. Do a disassembly of the code, check the vector table and associations with interrupts used and callbacks. That your routines linked in.

[SNata.1]

Hi Clive1,

Thanks. Actually transmission happens without an issue. We are able to copy files from device to PC and vice versa. The problem is the timing. How to improve or reduce cycle time. We are reading 512 bytes per read, so for a 4096 block, we need 8 such reads. Again, this current setup works fine.

[Tesla DeLorean]

A USB MSC or something else?

​

C​heck MSC_PACKET_SIZE definition, or something similar, don't recall, not at a computer.

[SNata.1]

it is USB MSC only. We declared our own variable for packet size as 512 bytes. HAL_SPI_Receive_DMA(&heval_Spi3, buf, USB_BLK_SIZ); declared USB_BLK_SIZ as 0x200

[Tesla DeLorean]

/* MSC Class Config */

#define MSC_MEDIA_PACKET                     8192

Allows for more efficient multi-block read requests from host OS

[SNata.1]

Thanks. We will try and update on the results.

[SNata.1]

If we change any value above from 512, the USB device is not recognized. PC cannot recognize our module.