ESP32 LOLIN SPI Problem

[p.erasmus]

Hi Ben/leigh.

I have an issue with the SPI on the ESP32 Lolin Board.

If there is no Prescale selected then the SPI is clocking and MOSI /MISO Is working ,If I select the Prescale anything below 10MHZ then there is no SPI
so from 8MHZ up 80MHZ seems to work and even no value for Prescale
secondly the CS/SS Pins does not work automatically it just makes a funny shape on the signal it is trying to do something .
If I use the SPI CS Enable and disable macro's the I can drive the High and low .
I need 4MHZ Clock for my ADC device to work correctly

P1.jpg (54.15 KiB) Viewed 8306 times

P_trace.jpg (74.22 KiB) Viewed 8306 times

CS Pin Controlled by Automode Property

P3.jpg (72.35 KiB) Viewed 8306 times

CS Pin Controled from a macro

CS-Pin.jpg (68.92 KiB) Viewed 8306 times

Test.zip

(2.37 KiB) Downloaded 587 times

[p.erasmus]

Hi Team,

I really understand you are very busy however it would be nice if I can get some help here, if it is me doing something wrong or is there a problem with the SPI,The post is open for a few days and I would like to move on with this in the new week

Appreciate you help

[LeighM]

Hi there
Sorry for delay.
(Doing a Google) it looks like the ESP32 SPI does not clock below 8MHz, which seems a bit strange.
If so, we are going to have to remove the options

Your auto CS is set on A5, but your pin drive is on A13
Is one a typo?

[p.erasmus]

Hi Leigh

That is just because I was playing with both pin 5 and 13 and some how the docs and code does not fit anymore and both work as IO's and when driven by myself with the CS commands/macros but when as CS pin with the auto CS function does not drive them for me Thanks for the info regarding the SPI clock may be we should remove the option

Thanks again then

[p.erasmus]

Hi Leigh

Can you please try this on your ESP32 board.
Auto CS does not work for me and also I noticed that 6MHZ clock working (Did not measure the time I will do to make sure it is really 6 and not 8 Mhz)

If I use Enable_CS and Disable_CS the CS pin as defined in the properties function, it is when I relay on Auto CS that there is no CS signal

May it it me I dont know

Test_2.rar

(980.79 KiB) Downloaded 702 times

Thanks

[LeighM]

Despite the word "auto" I don't think that the SPI component does anything with the pin other than via the Enable_CS and Disable_CS

[p.erasmus]

Leigh.

Ok I can do that in code however then it does not make much sense having a Property that can be selected to yes/ NO and actually are there only for cosmetic reasons

What I did in a component with PIC18, I have used the Enable /Disable_CS macro's inside my component macro calls and then if you select Yes the CS pins is driven and when select NO there is no actions on the CS pin . It does have some sort of effect what what only you guys know maybe would be good if you guys can tell us how to use this Auto Property ?

Thanks for your help appreciated

[BenR]

Hello,

The auto property I beleive gets rid of the CS pin property when set to no, forcing the user to control the CS pin themselves or not use a CS pin say if the pin not available or permanently tied to ground.

"Auto" is probably the wrong label, it should be more along the lines of "CS pin controlled by the component macros enable/disable".

[p.erasmus]

Hi Ben,

Sorry for my stupidity however I am still not getting what should happen when property is set to Yes ,
Should the SPI Component macro such as SPI Transaction automatically drive the CS pin or Not or is it the case
if CS is needed that regardless of the property setting the user should drive the CS pin in code

I am lost on this

[BenR]

Hello,

You either need the Auto property set to yes and to call the enable / disable macros or you set to no if there is no CS pin.


I've just tried 400KHz on ESP32 SPI hardware and it's working just fine. What specific speeds are you trying and i'll test those here.

I've seen the 8MHz reference Leigh has spotted but the text is pretty vague about what the limits actually are.