Photon Test Breakout Board

[rocksetta]

@ScruffR

For your setups with a second Photon I can't see how you power the second device? You have GND connected, but you might also want Vin or 3v3 connected.

Presently I just have them both powered by a usb cable, but you are correct If I use a PCB board I should use only one power source. On second thought for one of the serial connections I need the master to start before the slave which will be difficult if they are both powered together. I guess the reset button can achieve the same results.

@ScruffR

For I2C you want 4k7 pull-ups not 470Ohm.

Found this post

@AndyW

Frankly, for most hobby stuff, 2.2K-4.7K will work for anything but the most pathological fast bus (400KHz), and 4.7K-10K will work for slow (100KHz) busses.

Looks like I will change it to 4.7 K ohm. Thanks @ScruffR

@ScruffR

while(1) is usually used to trap your code in an eternal loop in case of an error condition.
But in this case it's meant as a very tight loop to avoid any overhead introducted between loop() - but this will only work with non-AUTOMATIC SYSTEM_MODE()

That may explain my problems with SPI. I really don't want to switch off AUTOMATIC SYSTEM_MODE(). I have several SPI programs to test from Arduino's and Raspberry Pi's, sure wish someone had already got the SPI Master and Slave working on a Photon.