Best signal counting MCU ?

Steve's picture

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Joined: Nov 10, 2020

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Best signal counting MCU ?
November 29, 2020 - 8:32pm

Hi,

Any suggestions on the best MCU for signal counting? I need to interpret a 50 MHz PWM signal and make my own control outputs from variable analog ( through a buck)  and digital outputs. I want mil spec or automotive "tough" chips too.

Steve's picture

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I meant to say 50KHz PWM

Sourav Gupta's picture

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Use pic32mz or 32 bit st.
You could choose renesas mcu also for automotive.

Steve's picture

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Thanks for the reply, I appreciate your input.

I totally goofed on the frequency, servos use only a 50 hz PWM, I think any PIC can handle that.

From other info I'm getting over at microchip forum it sounds like I need to focus on my analog outputs.

Someone suggested PIC18F16Q41 for it's peripherals and onboard DAC.

Remember from my other questions about simulating the throttle control for the eBike brushless hub motors....again this is an application that will be controlling those hub motors in the same way but will be using inputs from an OEM remote control car controllers reciever pack that controls standard RC type servos.

I have 2 50hz inputs, 1 binary digital input and 13 analog outputs, only 4 need to be variable.

I'm having trouble deciding if something like a DAC converter is the way to go or use something like the MikroE Buck 14 click board for the 100 mA (0.5-5V) variable analog outputs.

This project is for turning my lawn mower into a 4 wheel drive, zero turning radius, first person view robotic grass cutter :)

There are so many PICs and I find the data sheets are different, at least they seem that way to me, I'm hoping to find something close to what I need and just focus on learning that one and coming up with some code for it.

Thanks again.

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Actually I only need the 4 variable analog outputs, the other outputs could be binary digital, they are for a reversing relay arrangement of the 3 phase wires and also braking.

Sourav Gupta's picture

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Depends on cost. What is your level of concern about the price?

 

Lets say, you need 4 output where you could choose a simple mcu from pic without thinking the DAC portion where you just write the code and then choose a pic mcu that suits the size of the code and peripherals (I/O pins, CCP peripherals etc). Then go for 4 individual DAC or a single dac that has 4 output. Choose one depending on the changing resolution. If summing up all cost is still low for a mcu with 4 DAC output then go for it.

Other way is to drive a DAC based MCU that supports multi port output, I think that cost much, not sure through.

 

Hope this will help you.

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Thanks for the response, I guess I've been asking my questions the wrong way, I thought my video clearly showed what the output requirements would be, the buck output was at 100 mA between 0.5 to 5 volts only.

It turns out my best option is to just make a mosfet amplifier on the PIC analog output, that's all I needed, PWM based analog output is fine, I don't need DAC audio quality analog. 

As far as reading PWM signal for servos, I made a mistake, servo is only 50 Hz so any PIC CCP can read this.

Nevertheless I'm learning a lot, every response is valued and makes me think about how to build circuits and work with MCU, what are options etc etc.

Thanks