SPI not working

[PCA]

Hello, trying to connect an SPI device.
using GP14, GP15, GP16 as SCLK, MOSI, MISO.

Code: Select all

from machine import SPI
spi = SPI(0, SPI.MASTER, baudrate=2000000, polarity=0, phase=0, firstbit=SPI.MSB)

for i in range(3) :
    mydata = bytearray([1,2,3,4])
    spi.write(mydata)
    time.sleep(2)

checked with a scope :
MOSI seems OK but no activity on SCLK (High level)

tried to add a pull up/down resistor : no change
firmware is v1.5.2-71-gcb4fbc8

no more idea ...

Can you help ?

Pascal

[danicampora]

Hi,

I see that this is missing from the docs. The default SPI pins are GP14, GP16 and GP30. In order to select other pins you need to add the 'pins' tuple to the constructor:

Code: Select all

spi.init(mode, baudrate=1000000, *, polarity=0, phase=0, bits=8, firstbit=SPI.MSB, pins=(CLK, MOSI, MISO))

Example:

Code: Select all

spi = SPI(0, SPI.MASTER, baudrate=2000000, polarity=0, phase=0, firstbit=SPI.MSB, pins=('GP14', 'GP16', 'GP15'))

The PinOUT is here: https://raw.githubusercontent.com/wipy/ ... PinOUT.png

Cheers,
Daniel

[PCA]

Hi Daniel, thank you for the ultra fast answer!
Unhappily the issue is not solved.
My new code :

Code: Select all

from machine import SPI
from machine import Pin
cs = Pin('GP17',mode=Pin.ALT, alt = 7)
spi = SPI(0, SPI.MASTER, baudrate=200000, polarity=0, phase=0, firstbit=SPI.MSB, pins=('GP14', 'GP16', 'GP15'))
for i in range(3) :
    mydata = bytearray([1,2,3,4])
    spi.write(mydata)
    time.sleep(2)

MOSI is OK. CS is OK (due to my line cs = Pin('GP17'... ))
But GP14 (SCLK) always stuck high.
I checked the GP30 pin : no activity.

Pascal

[PCA]

Daniel,
mistake : GP30 is MISO (by default) so an input. no activity is just normal...
ignore my remark on this point.
Pascal

[PCA]

@danicampora
I suspect an hardware problem on my Wipy module.
I've just ordered a new one and will test again as soon as it arrives.
Pascal