STM32F103RB - USB - Packet memory too small

miki_pf · ‎2014-09-19

Posted on September 19, 2014 at 14:33

Hi All.

I'm working on a project which needs to send and receive audio stream with the size of packet - 288 bytes one way, - 576 bytes both ways. Problem is that the Packet Memory is only 512 bytes long and I have already used 320 bytes for other endpoints.

Is there a way around this, can the USB data be send or received without the need of going into the Packet Memory first but directly to SRAM??

Any other ideas how to solve this??

Thanks in advance

Marek

#stm32 #usb

tsuneo · ‎2014-09-19

Posted on September 20, 2014 at 01:57

Unfortunately, there is no way to bypass the packet buffer.

Isoc endpoints claim double (ping-pong) buffer on the packet buffer, in this USB engine. It makes the problem worse.

You may manage to run the jobs on the OTG_FS on STM32F105/7, F2, F4 (1.25 Kbytes packet buffer).

Even on this engine, double-size buffer is recommended, but single buffer still works under tight timing.

Tsuneo