MKR1000 SPI bus speed and can it be increased?

[IraSch]

I'm running an ILI9488 LCD display and it paints kind of slowly.

What is the default SPI speed on the MKR1000 and can it be changed? I thought I saw that the SPI speed can be set on some other processors.

Thanks.

[ptillisch]

Hi @IraSch.

@IraSch

What is the default SPI speed on the MKR1000

4 MHz:

arduino/ArduinoCore-API/blob/1.5.1/api/HardwareSPI.h#L55-L56

@IraSch

can it be changed?

Yes. The SPI library provides a speed configuration capability:

SPISettings - Arduino Reference

[IraSch]

OK, that makes sense but leads to some questions:

1-Can the MKR1000 support faster speeds (8MHz, 16MHz)?

2-The actual use of the SPI bus is buried in a library. Can I just call SPI.beginTransaction() with the modified parameter (and the 2 order and mode parameters) or would I need to go into the library, find its call, and modify it there. If the latter, I'm probably out of luck, since I really wouldn't want to change a [fairly] standard library .ccp and then have my change wiped out on a possible library update.

Thanks.

[ptillisch]

@IraSch

Can the MKR1000 support faster speeds (8MHz, 16MHz)?

Unfortunately I'm not very knowledgeable on this subject. Some of the other forum helpers are very knowledgeable so they will likely be able to provide an answer to your question.

@IraSch

The actual use of the SPI bus is buried in a library.

It will be necessary for us to take a look at the specific library to be able to effectively answer this. If you installed the library from the Arduino IDE Library Manager, please tell us the exact name of the library. Or if you downloaded it from the Internet, please provide a link to where you downloaded the library from.

[gilshultz]

Before worrying about a guess on the SPI being to slow it could very well be the processor is not keeping it loaded. Connect a scope or logic analyzer to the SPI bus and check it out. You can get a inexpensive "24 MHz" for less then two cups of coffee. Here is a link: https://www.aliexpress.us/item/3256807162946365.html? It comes with free shipping if over $10.00 but you you will need to purchase 3 to get that. It shows $4.95. You will have about a two week wait before it arrives. For about 6X you can get in a few days.

[IraSch]

@gilshultz

Before worrying about a guess on the SPI being to slow it could very well be the processor is not keeping it loaded. Connect a scope or logic analyzer to the SPI bus and check it out. You can get a inexpensive "24 MHz" for less then two cups of coffee. Here is a link: https://www.aliexpress.us/item/3256807162946365.html ? It comes with free shipping if over $10.00 but you you will need to purchase 3 to get that. It shows $4.95. You will have about a two week wait before it arrives. For about 6X you can get in a few days.

Wow! Thanks for the info. Never knew you could get one so cheap. I'm sure you get what you pay for, but at this price can't really go too far wrong. I'm ordering from Amazon - about $13 vs $1 (+ shipping) on Aliexpress, but I know I'll actually get it.

Thanks again.... now back to your regularly scheduled program ....