I am trying to interface PSOC 3 device (programmed as bulk transfer usb device) with labview through usb. I installed NI VISA driver for my device by setting VID PID values and updating driver in device manager. In "USB RAW-BULK" example given in NI EXAMPLES, i set visa resource name and IN endpoint of my device. When i start communication, only once data packet transfer from device to labview takes place, after that for every IN request by labview, device sends a NAK (& no data). I am analyzing this through USB Analyzer.
Can somebody suggest what is reason for that ? Reply ASAP because this is high priority project of Cypress.
Can you tell me how many data packets are you trying to send from the device? It requires you to understand the UART based communication which is formatted as 1 bit of start, 5-8 bits of data and one parity bit which is optional and finally one or two stop bits.
Can you tell me if you have checked your device functionality and whether it is giving you the correct data onr not on any other platform?
Also please refer to the following links if they are of any use.
Let me know also if you are getting any specific error? After first data what is happening? Is it giving you a timeout error or anyother error? please specify the error code it will be helpful to debug it faster.