I'm working on a custom board that uses a STM32F407 to send data across the network to another STM32F407 board using LwIP (no OS). I created an array of 100 bytes to use as a test program. It works fine as long as the array is declared as uint8_t. I am able to send 100 bytes and the other board receives all 100 bytes correctly.
If I declare the array as uint16_t, I only receive half of the bytes. I changed the array size to 40 as a further test. That results in only 20 bytes being received by the remote board.
If I look at the ethernetif.c file in LwIP, I see the following 2 lines that indicate what may be the problem.
__ALIGN_BEGIN uint8_t Rx_Buff[ETH_RXBUFNB][ETH_RX_BUF_SIZE] __ALIGN_END; /* Ethernet Receive Buffer */
__ALIGN_BEGIN uint8_t Tx_Buff[ETH_TXBUFNB][ETH_TX_BUF_SIZE] __ALIGN_END; /* Ethernet Transmit Buffer */
If I change the uint8_t Tx to uint16_t TX and try to compile I get these warning:
warning: passing argument 3 of 'HAL_ETH_DMATxDescListInit' from incompatible pointer type [-Wincompatible-pointer-types]
I have been working on this problem for a few hours but can't find a solution. The only thing I can think of (haven't tried) is to break the 16 bit data into two 8 bit data bytes and re-assemble on the remote end. But that is not really a desirable solution.
Has anyone else encountered this problem and found a work around?
