Cmod S6 outputs not working when running statdalone

[Ian]

This problem is strange. I've been using the Coolrunner II for over 20 projects. I saw the Cmod S6 Dip format and thought I would give it a try. I started with a simple program and got an external LED to flash at 1 Hz on Pin 1. The demo that comes with it also flashes the on board Led at 1 Hz. I simply just duplicated that. So good so far. Now here's the strange thing, When I remove the USB connection and then reconnect it or add the 5 Vdc power from a separate power supply, the on board LED flashes but the external one does not. If you measure Pin 1 you will see a hard voltage 3.3 vdc when open and 1.3 vdc when I have the external LED connected. It is no longer changing states. If I reprogram it without changing enything, it starts to flash again. I've tried a number of experiments from another CmodS6, different pins  and rebuilding the project from scratch with the same results. Has anyone else seen this or tried to run there's stand alone.

Thanks

 

[sbobrowicz]

Great news, glad it worked. Can you provide a link to the other post in case anyone else in need stumbles here?

Edit: Nevermind, I found it here: https://forum.digilentinc.com/topic/105-cmod-s6-quad-spi/ 

[sbobrowicz]

The CPLD on the coolrunner has internal non-volatile storage, which is why when you program it and remove power it still runs your design the next time it is powered on. The FPGA on the CmodS6 does not have internal non-volatile memory, so once it is powered off the configuration from the loaded bitfile goes away. Instead, the FPGA will look to the external SPI flash once it is powered on, and load the .bit file stored there (the .bit file stored there after manufacturing is our default demo). So, just to make sure I'm not barking up the wrong tree, did you program the SPI flash with your .bit file, or just the FPGA? If you only programmed the FPGA, we can teach you how to program the SPI flash.

[Ian]

That sounds exactly like what is going on. I've been using the Digilent Adept to load the .bit file into the Cmod so I assume that I am targeting the FPGA directly and not the SPI flash. Can you tell me how I would program the SPI flash.

Thank You

[Ian]

I found another post on how to program the SPI flash "Cmod S6 Quad Spi". Worked perfectly, Thank You

[lmarie]

I'm also getting to grips with the Cmod S6, and running into similar problems.

What cable are you using to program the SPI flash?

Is it the simple USB cable, via the Atmel chip, or are you using a USB-to-JTAG connector and the connections of header J4?

These details are not given in the other answer sbobrowicz alludes to, and they could probably be useful for other users.

Best regards,

[sbobrowicz]

J4 is actually a programming port for the Atmel part. The only way to program the FPGA (and the SPI flash) is with a USB micro cable. Ian is connecting to the Cmod S6 with a USB Micro cable.

[Ian]

I used a simple USB to micro adapter cable, it was actually for my phone originally so nothing special about it. Instead of using the Digilent Adept to load the file you had to use the Xilinx ISE IMPACT to program the flash directly. It used the same USB cable which I was surprised at, I thought I would have to use a special USB Xilinx Programming Cable but it found the flash straight away and had no issues programing it. The only difference was that it took a lot longer to complete.

[lmarie]

OK, many thanks to you. Looks like the USB cable I'm using may have been in use for too long...

Best regards