AnsweredAssumed Answered

need some project advice :)

Question asked by pirie.russell on Oct 7, 2012
Latest reply on Nov 4, 2012 by pirie.russell
Hello :)

I have a little project using a stm32f4 which receives usb data from the pc using the cdc classes (2048bytes @ 60fps) and then draws them to a Plasma dot matrix display.

I have it all working ok :) The problem is, the dot matrix display needs to be continually refreshed to keep the image on it /create different shades of colour. When i am not sending usb data the image is fine, nice and stable. But when i start sending the usb data at 60fps it starts to flicker slightly. This is because the cpu is going off to do the usb stuff and taking cpu time away from updating the display :(

is there any way around this? is the cdc class pure interrupt driven? is there a way i can tell it when i want it to run its usb functions. (basically i control the cpu time)

I have had this problem with other microcontrollers but was hoping the speed of this one would solve the problem. only way i have managed to successfully solve the problem is use a FPGA+FTDI but this is quite expensive and was hoping i could do the whole thing just with one stm32f4

any advice would be much appreciated.