How Many PWM Outputs Can a PSoC 3 or 5 Generate?
An interesting question that I've gotten several times is how many instances of a specific function can be placed into a PSoC 3 or 5
. This question is particularly interesting for PSoC since unlike typical micro controller alternatives, the quantity of a specific digital function that is present in a PSoC isn't a fixed small number. If your application demands that the entire programmable digital array be used for just one function type, then you have that option. Specifically it can be interesting to look at how many PWM outputs can be generated by a single PSoC 3 device. The digital array (UDB array) has 24 UDBs . Each of those UDBs can be used to create an 8-bit PWM. Each of those PWMs can generate 2 independent outputs. They have the same period, but the duty cycle is independent. So if the entire array is dedicated to generating PWM outputs, then 48 PWM outputs can be generated. To make sure there aren't any gotchas, the video shows a design that includes 48 PWM outputs along with the utilization report showing the resources used. If by chance, 48 PWM outputs is not enough you can squeeze 4 additional PWM outputs from the fixed function counter/timer/PWM blocks. I've not used those in the designs shown here, but they are available and can be used to provide 4 extra single output PWMs. So the correct answer to the question posed by this post is 52. The next question is what to do with all of these PWM outputs. There are many real world examples where a large number of signals that have individually controllable PWM signals would be useful. For this example I'm going to use them to control the brightness of LEDs. In particular I've built a design that uses RGB LEDs, so I'll need 3 PWM outputs for each LED in order to control the three color components. This will allow the creation of 16 Million possible colors since each of the color components can take on 256 distinct levels of brightness. I didn't want to breadboard up a system with 16 of these LEDs, so to prove the concept I've used just 2 of the RGB LEDs. To make it a little more interesting I've used the CapSense capability of PSoC to control the LEDs. I'm using the 2 CapSense buttons on the DVK to select the LED and the color component and then using the slider to control the brightness. To Know more about PSOC visit Cypress's website http://www.cypress.com/How Many PWM Outputs Can a PSoC 3 or 5 Generate?
By: Dave Van Ess