nRF52840 2 SPI instance use different clock to 2 devices

RE: nRF52840 2 SPI instance use different clock to 2 devices

qleung — Mon, 02 Nov 2020 01:09:04 GMT

Sorry i not expression that clearly, actually i need the flash memory working on at least 40 MHz, that my mistake and thanks for your help.

RE: nRF52840 2 SPI instance use different clock to 2 devices

awneil — Mon, 02 Nov 2020 00:45:32 GMT

You said the EEPROM was the 40 MHz device - EEPROMs do not generally have a minimum clock frequency.

RE: nRF52840 2 SPI instance use different clock to 2 devices

qleung — Mon, 02 Nov 2020 00:39:27 GMT

Hi Awneil,

Device A lowest working frequent is 40MHz and Device B maximum working frequent is 10MHz, so i need two different frequent base SPI.

RE: nRF52840 2 SPI instance use different clock to 2 devices

awneil — Mon, 02 Nov 2020 00:35:51 GMT

RE: nRF52840 2 SPI instance use different clock to 2 devices

qleung — Mon, 02 Nov 2020 00:35:00 GMT

Hi Einar,

Thanks for your answer, now i know how does that work!

RE: nRF52840 2 SPI instance use different clock to 2 devices

awneil — Fri, 30 Oct 2020 15:50:17 GMT

[quote userid="95009" url="~/f/nordic-q-a/67762/nrf52840-2-spi-instance-use-different-clock-to-2-devices/277695#277695"]those frequencies are devices specification ferquncy range[/quote]

Again, aren't they just the maximum limit to the range - not a requirement that they work exactly at those specific frequencies ?

RE: nRF52840 2 SPI instance use different clock to 2 devices

Einar Thorsrud — Fri, 30 Oct 2020 15:34:28 GMT

Hi,

[quote user="qleung"]use legacy SPI, it is can work in same time with different clock(like set general gpio to PWM and MOSI、MISO) too?[/quote]

The legacy SPI peripheral are also independent, so yes, you can use different clocks on the different SPI peripherals at the same time.

RE: nRF52840 2 SPI instance use different clock to 2 devices

qleung — Fri, 30 Oct 2020 00:40:46 GMT

Hi Awneil
Appreciate your detail explanation, but i also want to know if don't use SPIM but use legacy SPI, it is can work in same time with different clock(like set general gpio to PWM and MOSI、MISO) too? Because those frequencies are devices specification ferquncy range.

Thanks

RE: nRF52840 2 SPI instance use different clock to 2 devices

awneil — Thu, 29 Oct 2020 09:22:32 GMT

[quote userid="95009" url="~/f/nordic-q-a/67762/nrf52840-2-spi-instance-use-different-clock-to-2-devices"]the sensor spi clock is use 10 MHz and the EEPROM is 40MHz[/quote]

Surely, those are just the maximum specifications for those components - they don't have to be those specific frequencies?

Check the datasheets for the parts!

Give manufacturers, part numbers, and datasheet links for the slaves - so people can verify.

You can find the nRF52840 Product Specification (and other documentation) here:

https://infocenter.nordicsemi.com/topic/struct_nrf52/struct/nrf52840.html

The Block Diagram shows you that the nRF52840 has three SPIM modules:

infocenter.nordicsemi.com/.../blockdiagram.html