- Add .dma_buf section in RAM_D1 for DMA-accessible USART instance pool.
DTCM (0x20000000) is not reachable by DMA on STM32H7, causing bus errors
(TE) when DMA writes to malloc'd buffers placed in DTCM by the XG linker
script.
- Replace malloc with static pool (usart_pool[]) placed in .dma_buf section.
- In RxEventCallback, set recv_buff_size from Size so module callbacks know
how many bytes were actually received.
- Use USART_RXBUFF_LIMIT (256) as the DMA transfer size instead of per-module
recv_buff_size. The actual buffer is always 256 bytes.
- Remove recv_buff_size from USART_Init_Config_s; it is now set at runtime.
- Flush RDR, clear error flags, and clear stale DMAR in error callback to
prevent residual conditions from re-triggering errors on DMA restart.
- Switch Vision module from UART10 to UART1.
SkyLiCoder
88702e2832