SOLVED - ISP with more than one SPI device on board?

Other Hardware General Electronics
1

I'm designing a PCB which includes an ATTiny84 connected to an RF transceiver via SPI.

However, this is going to be a dev/test platform so I'm going to be reprogramming the ATTiny repeatedly so have include an ISP header.

However, the though occurs that if I use the ISP, does the software (I'd intend using the Arduino environment with a Sparkfun TinyAVR programmer) look for the relevant device IDs and programs the right one or do you need to isolate the device?

I'm using SMDs so unplugging isn't an option.

Thanks for any help, it's my first time doing anything permanent using an ISP rather than the Arduino serial uploader.

2

AVR programmer will pull reset low to put attiny in ISP program mode. That will tristate all IO pins. If the IO pin you use for the RF device has a pullup resistor, that should keep the RF device off the SPI bus and provide the isolation you need.

3

CrossRoads:
... If the IO pin you use for the RF device has a pullup resistor, that should keep the RF device off the SPI bus and provide the isolation you need.

To be clear, the IO pin that Crossroads is talking about is the one connected to the /CS input of the RF device.

4

Thanks guys

I appreciate the clear simple answers, as always