CANOpen SDO write buffer corruption when writing less data bits than the previous data write

[gpender]

Hi Ulrik,

Observing the CANbus when writing SDOs, a UINT32 with value 0xFFFFFFFF and then immediately writing a UINT8 with value 0x0C the value seen on the CAN bus is 0x0CFFFFFF. This creates a problem for the target CAN device I am using and throws it into an Emergency State.
To overcome this problem I have changed your code to reset to 0x00 the 4 data bytes in the buffer: not particularly elegant but it does seem to work.

canOpenStatus SDO :: setData(u32 val, u8 valid, u8 *n)
{
canOpenStatus ret = CANOPEN_ERROR;
if (valid > 0 && valid <= 4)
{
this->can_data_tx[4] = 0x00;
this->can_data_tx[5] = 0x00;
this->can_data_tx[6] = 0x00;
this->can_data_tx[7] = 0x00;
if (valid == 1)
{
::setU8Val((u8)val, this->can_data_tx, 4);
}
else if (valid == 2)
{
::setU16Val((u16)val, this->can_data_tx, 4);
}

I hope you can fix this issue for me, in the meantime I will use a modified version
Kind Regards
Guy Pender