FIFO push all values as vector

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Tamar 2023-7-11

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评论： Jon 2023-7-18

Hi, I want to pop the fifo every step time (1 sec) and push all the values as vector every 5 steps (5 sec). I didn’t find way to push more then one value every step time

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Jon 2023-7-11

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fifoEx.slx

I assume you are using the Queue block in the DSP System Toolbox in Simulink.

If so you should supply the In port with a 5 element vector input, then supply the Push port with the output of Pulse Generator with 5 second period, and the Pop port with the output of a Pulse Generator with a 1 second period.

You may want to delay the start of popping until the buffer is full.

See my attached example

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Jon 2023-7-12

在 MATLAB Online 中打开

I think this approach may work for you. I have use a tapped delay line to buffer the values. I detect a zero following a non-zero pulse train (e.g. the zero following 3 6 3 in your example). When I detect this zero, I trigger a triggered subsystem that hold the MATLAB function block. and receives the entire contents of the FIFO (output of the tapped delay line). Inside the function block I extract just the most recent pulse train, with some additional logic, and the compute the desired function of the pulse train values.

I have attached the model demonstrating this saved as version 2022a. Hope you can open and run it Also here is a screen shot for an overview. Below is the code inside of the MATLAB function block.

Note this approach won't find a final non-zero pulse train at the end of the simulation unless the last element in the input is a zero, so you may have to be careful about that edge case.

function y = fcn(u)
% function to do demonstrate doing something
% with group of pulse inputs
% u is output of tapped delay line, which essential acts as FIFO buffer
% Function is executed at end of non-zero pulse train, since u is entire
% contents of FIFO, and non-zero pulse trains are variable length, there
% may be some previous pulse trains and/or zeros in the buffer
% Just keep the newest non-zero values
idx = find(u==0,1,'last');
% Note even though idx has only one element, it seems that Simulink doesn't
% know this and has errors unless you just use the first element of this
% one element vector, so use idx(1), rather than idx
iStart = idx(1) + 1; 
x = u(iStart:end,1); % just the most recent pulse train
% Calculate something using the non-zero pulse train, I will compute the
% total, but you can insert what you want here
y = sum(x);

Tamar 2023-7-18

I tried to not use buffer. I did something and I think it worked. Thank you anyway, you help me a lot!!

Jon 2023-7-18

Hi Glad you found a solution. I and maybe others would be interested to see your approach without a buffer. Could you attach a simple model that demonstrates the idea.

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