Issue in config.py

[anthony9999]

Apologies for the newbie question, but I having trouble with the follow bit of config.py .. as in its not clear to me how i switch from hardware to software, and how I assign the pins if software,..

#######################################

SPI pins if you choose Hardware SPI

#######################################

On the raspberry pi, you MUST use predefined

pins for HW SPI. In the case of the adafruit-31855, only 3 pins are used:

SPI0_SCLK = BCM pin 11 = CLK on the adafruit-31855

SPI0_MOSI = BCM pin 10 = not connected

SPI0_MISO = BCM pin 9 = D0 on the adafruit-31855

plus a GPIO output to connect to CS. You can use any GPIO pin you want.

I chose gpio pin 5:

GPIO5 = BCM pin 5 = CS on the adafruit-31855

Note that NO pins are configured in this file for hardware spi

#######################################

SPI pins if you choose software spi

#######################################

For software SPI, you can choose any GPIO pins you like.

You must connect clock, mosi, miso and cs each to a GPIO pin

and configure them below based on your connections.

#######################################

SPI is Autoconfigured !!!

#######################################

whether you choose HW or SW spi, it is autodetected. If you list the PINs

below, software spi is assumed.

Specifically, if I want to use software SPI how do I do it? I wired up my PIzero to MAX31855 in the following manner:
3Vo to Pin 1 (3.3v DC)
GND to Pin 9 (Ground)
DO to Pin 11 (GPIO 17)
CS to Pin 13 (GPIO 27)
CLK to Pin 15 (GPIO 22)

based on https://www.instructables.com/Build-a-Web-Enabled-High-Temperature-Kiln-Controll/

so what lines and where do I put in config.py to support this?
thanks

[rock1148]

I use software SPI and this is what you should do to identify the pins you've wired to your Pi
Just look at the config.py and find this section:

spi_sclk = board.D15 #spi clock
spi_miso = board.D17 #spi Microcomputer In Serial Out
spi_cs = board.D13 #spi Chip Select
# ignore this: spi_mosi = board.D10 #spi Microcomputer Out Serial In (not connected)
gpio_heat = board.D23 #use whatever pin you'll connect to the relay relay

[hmsjel]

Hi
Maybe I stupid
I have the same problem, cant figure out what pin I should use.
I use an RPI 4B.
Can some one explain in clear text what do do.

[rock1148]

Where the config.py states "board.D15" that means that you should connect the rpi from pin 15 to the pin labelled clock on the amplifier (31855 or 31856). When you see "board." it is referring to the rpi and where you see "#spi" it refers to the thermocouple amplifier.

I hope that clarifies things for you.

[hmsjel]

@rock1148
Thank you very much
now it makes sense to me