Good morning
Started on a project where a STM32F2 series MCU plays the role of a GPIB device...
According to the GPIB protocol pictures I've found the start of a communication from a GPIB controller looks like:
- Wait for NRFD is 1
- Set DIO on the bus
- Set DAV to 0
- Wait for NDAC for 1
- Set DAV to 1
So in my init code I have:
// Drive SN75160
HAL_GPIO_WritePin(GPIOE, TE, GPIO_PIN_RESET);
HAL_GPIO_WritePin(GPIOE, PE, GPIO_PIN_SET);
// Drive SN75161
HAL_GPIO_WritePin(GPIOE, DC, GPIO_PIN_SET);
HAL_GPIO_WritePin(GPIOD, NDAC, GPIO_PIN_RESET);
HAL_GPIO_WritePin(GPIOD, NRFD, GPIO_PIN_SET);
HAL_GPIO_WritePin(GPIOD, SRQ, GPIO_PIN_SET);
But I don't see anything happening with the DAV signal being set to 0 when sending a command...
As soon I attach another device on the GPIB bus I see the DAV signal being driven low.
So I assume I missed some other signal which is not set correctly besides NRFD, NDAC and SRQ?
thanks in advance
davorin