Hi Jes,

Since my previous project was finished I was thinking of prototyping this 
frequency counter in JAL. My idea is to use it in combination with an SSD1306 
display and test it using the library I created for the Si5351 although the 
range will be limited of this frequency counter.

I think of making it 'auto ranging' as to increase the frequency range indeed 
by changing prescaler values as you mentioned to measure lower frequencies. I 
do not yet know how low it can measure.

I might even post it on Instructables as prototype. I saw some examples there 
based on Arduino but most of them are very simple, that is no auto-ranging and 
so limited in the range it can handle.

I started today, not sure how long it wil take but when it is done I will post 
the source file on Jallib or on Instructables.

BTW I will base it on a PIC16F1823 since that is the one I often use in my 
projects but you can use other PICs as long as it has the capture function. As 
said I do not know how long it will take so don't wait for it 🙂.

Kind regards,

Rob

________________________________
Van: [email protected] <[email protected]> namens Jesito's μFabLab 
<[email protected]>
Verzonden: zaterdag 5 september 2020 09:55
Aan: jallib <[email protected]>
Onderwerp: Re: [jallib] Some help needed to measure pulse length

Many thanks Rob. I have to figure out how to do it. Is the timer working at the 
MCU clock speed?. If so the 16 bit value might be too small to hold the pulse 
length for i.e. a 5 sec pulse, isn't it?. I suppose some prescaling should be 
done there... Have to investigate and read more on that.
Kind regards.
Jes.


El jueves, 3 de septiembre de 2020 a las 18:51:51 UTC+2, [email protected] 
escribió:
Hi Jes,

I just checked but I was mistaken, there is a procedure that calculates a value 
for the timer based on a frequency.

If you want to measure the length of a pulse you can use the capture mode of a 
timer which is available in many PICs, for example the 16F1823.From the 
datasheet:
Capture mode makes use of the 16-bit Timer1
resource. When an event occurs on the CCP1 pin, the
16-bit CCPR1H:CCPR1L register pair captures and
stores the 16-bit value of the TMR1H:TMR1L register
pair, respectively. An event is defined as one of the
following and is configured by the CCP1M<3:0> bits of
the CCP1CON register:
• Every falling edge
• Every rising edge
• Every 4th rising edge
• Every 16th rising edge
When a capture is made, the Interrupt Request Flag bit
CCP1IF of the PIR1 register is set. The interrupt flag
must be cleared in software. If another capture occurs
before the value in the CCPR1H, CCPR1L register pair
is read, the old captured value is overwritten by the new
captured value.

Kind regards,

Rob

________________________________
Van: [email protected] <[email protected]> namens Jes 
<[email protected]>
Verzonden: donderdag 3 september 2020 13:45
Aan: [email protected] <[email protected]>
Onderwerp: Re: [jallib] Some help needed to measure pulse length

Thanks Rob, I look for it, just what I needed to know :0)

El jue., 3 sept. 2020 12:01, Rob CJ <[email protected]> escribió:
Hi Jes,
I thought there is already a Jal library to measure the width of a pulse 
created by Matt. Would that do the job?

Met vriendelijke groet,
Rob Jansen
________________________________
From: [email protected] <[email protected]> on behalf of Jesito's 
μFabLab <[email protected]>
Sent: Thursday, September 3, 2020 10:49:48 AM
To: jallib <[email protected]>
Subject: [jallib] Some help needed to measure pulse length

Hello,
I'm new to JAL and I would like to measure the length of some pulses that can 
be as long as 5 sec and as short as 1/8000 of second.
I have a handful of different pics, but ideally I would like to use a small 
one, I just need one pin for the pulse, two more to interface to an I2C small 
display and one more to reset and restart the measure.
Could anyone point me to an example that could guide me through this?.
I love the cleanless and simplicity of JAL.
Thanks in advance.
Jes.

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