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UART counts double?

Posted: Sun Feb 19, 2017 1:43 am
by MJU
I'm trying to get a NRF24L01 working with the FC7 component.

This works with the UART component I think.
The last evenings I was trying to send just 1 number via the component, but when I watch what is send via the UART (logic analyser), I see that the number is doubled.

In the attached flowchart I see that the initialisation is done the correct way (looks familiar with the code I've written for V6) :-)
But, as soon as the random number is send (register 0 = 1) I read a "2" on the analyser.
Register 5 = 0x11, and the UART sends 0x22..

Again a timing error?
The strange thing is that the initialisation is done with the right settings:

0.100181937500000,SPI,MOSI: 0x24
1.387201750000000,SPI,MOSI: 0x4F
1.387204375000000,SPI,MOSI: 0x26
1.387248125000000,SPI,MOSI: 0x07
1.387250750000000,SPI,MOSI: 0x3C
1.387294562500000,SPI,MOSI: 0x00
1.387297187500000,SPI,MOSI: 0x27
1.387340937500000,SPI,MOSI: 0x70
1.387343562500000,SPI,MOSI: 0x40
1.387387375000000,SPI,MOSI: 0x4C
1.387390000000000,SPI,MOSI: 0xE2
1.387433687500000,SPI,MOSI: 0xE1
1.387477437500000,SPI,MOSI: 0x2A
1.387522500000000,SPI,MOSI: 0x11
1.387525125000000,SPI,MOSI: 0x11
1.387527750000000,SPI,MOSI: 0x11
1.387530375000000,SPI,MOSI: 0x11
1.387533000000000,SPI,MOSI: 0x11
1.387535625000000,SPI,MOSI: 0x30
1.387578875000000,SPI,MOSI: 0x11
1.387581500000000,SPI,MOSI: 0x11
1.387584125000000,SPI,MOSI: 0x11
1.387586687500000,SPI,MOSI: 0x11
1.387589312500000,SPI,MOSI: 0x11

Re: UART counts double?

Posted: Mon Feb 20, 2017 11:52 am
by Benj
Hello,

The nRF24L01 component uses SPI which unlike UART is clock driven and so as long as the data is in time with the clock the actual data rate has no real effect.

However as your using hardware SPI the data rate should remain constant for the duration of your program.

You have the SPI prescaler set to Fosc /2 or 8MHz which is pretty fast, maybe try increasing the prescaler setting a bit and see if this helps.

Re: UART counts double?

Posted: Mon Feb 20, 2017 4:12 pm
by MJU
I have tried several settings for the OSC.. but the error remains.

I have tried the "naked" flowcharts I have made for V6 (and which are the base for this V7 component I think).
And this works fine with the OSC settings..

I was wrong naming the SPI Uart in my original post..

Re: UART counts double?

Posted: Wed Feb 22, 2017 6:46 pm
by MJU
I think I found it.

There was a problem with my logic analyser and the speed of the SPI didn't do any good.
I reduced the speed and managed to get my logic analyser working right.

Thanks