Author Topic: VNC2 SPI Slave to USB Host  (Read 10403 times)

matchesman

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VNC2 SPI Slave to USB Host
« on: January 28, 2014, 08:04:08 am »
Hi, I'm working on a project where I need to save data to a usb stick, at a rate of about 10 kB/s. I'm using FTDI's Vinculum II. I managed to send data to the VNC2 with the fifo interface and write it to a usb stick, and it works pretty well, but I would like to use the spi slave interface of the VNC2 instead, to free so pins that I could use for GPIOs.That's where I have problems. I used the "SPI to USB Memory Sample Application ROM" as a starting point, but I am not able to read data from the SPI port. I can see with a logic analyzer that I'm sending data from the master though. I tried different slave modes, and SCK speeds with no success. In Full duplex mode, when the master sends a write command byte, the VNC2 replies that it can receive new data, but when the master sends the first data byte, the VNC2 automaticaly replies that It cannot receive data. And even this single data byte is not available from the spi driver. Finally, I tried to contact FTDI support, with no success.

Anyone can help?

Jan Axelson

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Re: VNC2 SPI Slave to USB Host
« Reply #1 on: January 28, 2014, 10:02:50 am »
No specific advice, but John Hyde's free ebook might have something:

http://www.ftdichip.com/Support/Documents/TechnicalPublications/USBDesignByExample.htm

Annoying that the example code doesn't work!

Systronik

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Re: VNC2 SPI Slave to USB Host
« Reply #2 on: February 21, 2014, 02:24:46 am »
Hello,

Did you already find a solution for your problem?
I have also tried to contact FTDI support without success.

I am running into the same problem as I try to use the VNC2 device for reading data from a FTDI serial cable and sending the data via SPI Slave to our host processor. Sending data from our host processor to the VNC2 over SPI Slave worked out of the box, but the other way is still a mystery. We have to finish our product in March, so we try to do everything to get it to work.