Arduino Due how to connect 8 spi devices

Using Arduino Project Guidance
#1

Hi

I am developing board that will have 8 SPI chip that needs to communicate with an ARM microcontroller and I need to figure out how to connect them. I would like to have my ADC on separate hardware SPI than rest.

Below is the list of stuff I need to connect,

  1. Ethernet (W5500) x1
  2. SD card x1
  3. Flash (AT25SL641-MHE-T) x 1
  4. ADC (ADS8688) x 4

So base on my understanding I can use:

  1. Ethernet : PA28(111) Ethernet CS and PA25,PA26, and PA27 for MISO, MOSI,SPCK
  2. SD Card: PA29(112) SD Card CS, and same SPI as Ethernet
  3. Flash: PC29(102) Flash CS, and same SPI as above
  4. ADC: I don't know what to choose for chip select and MISO, MOSI, SCK

Please let me know if you have any questions.

Thank you

#2

CS = ChipSelect

That pin must be unique for each device, and can be any I/O pin.
The other (data) pins are shared.

The ADS8688 has a CS pin (pin38).
SDI, SDO, SCLK, MISO, MOSI, SCK, :o
Leo..

#3

@Leo Thanks for the reply, I understand that each Cheap select needs to be unique, but do I have to share, data with other ICs(there is a single SPI data in DUe), since this will slow down the data.

#4

Yes. When a device is 'de-selected', it's not talking/listening to the SPI bus.

The Due has a single core processor, so can only do one thing at the time.
But usually so fast that for the user it seems it's all happening at the same time.
Leo..

#5

Thanks for the answer

#6

Notes:

1/ The USART peripheral is usable in SPI mode too.

2/ There is a TurboSpi library for the DUE (leverages SPI DMA)

#7

@Ard_newbie I did not know that thanks

#8