You are here

UVC_AN75779 fails to work after I change the data-width to 32-bits. | Cypress Semiconductor

UVC_AN75779 fails to work after I change the data-width to 32-bits.

Summary: 2 Replies, Latest post by lis_user1 on 10 Oct 2016 02:26 AM PDT
Verified Answers: 0
Last post
Log in to post new comments.
lis_user1's picture
User
32 posts

Hi Cypress, 

I am experimenting with FX3 application note AN75779. 

I use FPGA to replace the image sensor and removed all sensor related I2C transactions in FX3 firmware. 

The FPGA generates 32-bit data and follows the FV/LV protocol in AN75779. With original fx3_uvc.cydsn I could stream in the LSB of my data. 

 

To adjust for the data width I changed that to 32 bit in fx3_uvc.cydsn. I also changed step size in LD_ADDR_COUNT & LD_DATA_COUNT to 4. 

It failed to work after that change. 

What should I do now? 

Thank you! 

 

Malik Bathusha's picture
User
2 posts

hi,

Check your system Clock frequency. you use 32-bit so enable the SysClk400 in CyU3PDeviceInit.

lis_user1's picture
User
32 posts

Thank you. It works now. 

How long is the latency from INTR_CPU to CyU3PDmaMultiChannelCommitBuffer? With 100MHz and 16KB buffer, one would expect to interrupt to hit & commit every 40us. Is the CPU fast enough to add header in that 20000 cycles? 

 

Log in to post new comments.