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PSoC™ 5, 3 & 1 Forum Discussions

muhuc_4026131
Level 1
Level 1
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Hello everyone,

I have recently come across PSoC 5LP. I am working on a project where I have to generate three frequencies to run the TCD1304DG CCD. The three frequencies are Master Clock (2 Mhz), Shift Gate (SH-Pulse) and Integration Clear Gate (ICG). I am able to generate 2 MHz from the master clock and I can also use the PWM function but I am unable to the specific clocks and delays given in the figure below.

Capture.PNG

This translates to the following:

  1. SH must go high with a delay (t2) of 500 ns after ICG goes low.
  2. SH must stay high for (t3) a minium of 1000 ns.
  3. ICG must go high with a delay (t1) of 5000 ns after SH goes low.

I have used several codes that are available online for Arduino Uno and Arduino Mega ADK but I want to use my PSoC 5LP. I would appreciate your help guys. Cheers.

Zaryab

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1 Solution

So here's something I mocked up, but haven't tested:

2019-02-22_9-20-10.png

Do be careful with the LUT as it normally would be backwards for a down counter (click on the input hex value twice to sort in reverse order).

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4 Replies
ScottA_91
Employee
Employee
10 solutions authored 100 replies posted 50 replies posted

First, I wouldn't set the IMO to 2 MHz.  I would put down a clock component, set that to 2 MHz and let the system take care of dividing the clock down for you.

I can see a couple of ways of doing this:

If you just want to do this on a regular basis, use a lookup table and a down counter.  (Use the lookup table to disable the down counter, use the count to change states, register the lookup table outputs, and use a control to reset the down counter to start this action.)  No code needed, meeting timing should be pretty easy and it should be very reliable.

Alternatively, you can do all of this in a datapath, with the different states time slices you want.  The advantage here is less resources, but it is more difficult to do and understand.

You *might* be able to make timing bit banging things via the CPU, but I think using pure hardware is a better way to go here.

Thanks for your reply ScottA_91 . Really appreciate it. I have looked into LUT and down counter and I understand what you're suggesting. The problem is I don't know how to implement what you just said. Would you be able to elaborate your first suggestion please? I am trying to meet the time requirements for the CCD and I hoping to keep these fixed these once they work. Cheers.

So here's something I mocked up, but haven't tested:

2019-02-22_9-20-10.png

Do be careful with the LUT as it normally would be backwards for a down counter (click on the input hex value twice to sort in reverse order).

Thanks a lot. sorry for the late reply. This is looking promising. I will try it and report back. Cheers.

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