Raspberry PI SPIdev always returns 0 when reading lightning detector register

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1

Hello,

I am trying to use the lightning detector with a Raspberry Pi. I haven’t seen any librarys that are available using the SPI interface, since the I2C is “not supported” for this product.

Using SPIdev, I am trying to read the registers, but always returns zeros, no matter what register I try to read.

I did try connecting the SPI read and write pins together to test as a loop back, and I was able to see data.

First I am confused as to if the CS pin is an active low or an active high. Looking at webpage for the lightning detector it seems to indicate a silkscreen issue. When looking at the spec for the chip, it says it is an active low, and on the schematic for your board it shows a pullup resister, which would indicate it is an active low.

Here is the code that I am using to try to read the register…

import spidev

spi = spidev.SpiDev()

spi.open(0,0)

spi.max_speed_hz = 244000

spi.mode = 0b01

x = spi.xfer2([0x40,0x00])

print(x[0])

print(x[1])

spi.close

I have also tried to use the following and get the same results…

changed x=spi.xfer2 to:

spi.writebytes([0x40, 0x00]) #0x40 set to read mode and register 0

x=spi.readbytes(2)

print(x[0])

print(x[1])

lightning Detector is connected to Raspberry Pi as follows:

pin 19 (MOSI) to MOSI on lightning detector board

pin 21 (MISO) to MISO on lightning detector board

pin 23 (SCLK) to SCLK on lightning detector board

pin 24 (CE0) to CE on lightning detector board

Any help in finding what I am missing here would be greatly appreciated

2

If your wiring labels are correct you need to swap the MISO ↔ MOSI (MISO from the sensor goes to MOSI for the Pi and vice-versa). Also, just to be sure, SPI is enabled on the Pi?

3

Thanks for the reply and advice.

I quadruple checked to make sure SPI is enabled.

I swapped the wiring between the input/output data lines and still only getting 0x00…

4

Darn. Do you have another device you can test? (either another MCU with SPI, or another sensor with SPI?)