Arduino Due for SPI with raspberry pi

Official Hardware Mega Due
1

I'm going to communicate Arduino Due and raspberry pi via SPI. Earlier i did between UNO and Raspberry pi.

I have questions with Due.

1.What is maximum SPI clock speed supported by Due?

2.Is a level shifter is needed between Due and rpi?

3.When i go through data sheet i found 6 SPI channel's are available. But physically i cant find pins 6 separate channels.

Thanks
Venkatesh

2

  1. I belive you can get up to 42Mhz on the spi

  2. both the due & the pi are 3.3vdc so no level shifter requierd

  3. i don't understand your question -
    are you asking about the the spi periperal ? the xmit & recv are shared between periperials (of which you can have upto 15**)
    or are you asking about other spi - the usarts can be used as spi ...

**don't recall if all the CS lines are available

3

Hi ralphnev,

ralphnev:

  1. I belive you can get up to 42Mhz on the spi

I heard only quarter of clock speed of board can be configured for SPI. If 42MHz u mean SPI_CLOCK_DIV2 right?

For question 3, as mentioned in datasheet there are 4 Tx,Rx available physically(0,1,14-19). Im asking about 6 SPI channels? I able to find only one spi channel of pins (MOSI 75,MISO 76,SCk 74). What about other physically?

Question 4: Maximum SPI clock speed in Rpi is 16MHz so need to configure Arduino Due to 16MHz. How to do it if possible?

Thanks
Venkatesh

4

from the data sheet AT91SAM3x shows 2 'pure' SPI (Table 33-2,33-3) & 4 'USART' SPI (Table 36-1+36-3)

the USART & pure SPI are not setup the same way - esp for DMA /PDC
& as far as the wiring you would have to trace the info in the tables above to see if they are all brought out to aa location that is useable

many lines have mutiple functions

from the data sheet it does look like you could program spi clk to be MCLK/1 but i doubt many perhierals could tolerate that ...
which is slave which is master between the PI & DUE ?
master will set the clock slave doen't care (as long as it is fast enough ...)

5

In my case Rpi is master. So max clock speed b/w pi and Due will be 16Mhz. Is it possible to configure 16MHz by using 5.25 divider?

6

again
master will set the clock, slave doesn't care

you set the PI to 16Mhz , it has a clock OUTPUT
i have not looked on how to set the clock on the PI

you do not set a clock for the slave(DUE) - it has a clock INPUT

7

ralphnev:
2) both the due & the pi are 3.3vdc so no level shifter requierd

Why there is 5v and GND pin near to SPI pins

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