I'd appreciate it if someone could offer a couple of suggestions about pairing up an AVR MCU (I'm thinking about using the MEGA162V-8PU ) to a general ISM < 1GHz (transceiver), and the ATTINY85 on the other end (with another transmitter). Architecturally, my system is similar to an RF garage opener. There is a base station (using the MEGA162V-8PU) that has 2 sensors connecting to it. In terms of the preferred PHY protocol for the transceiver I was thinking about using the IEEE 802.15.4 (LRWPANs) as it allows for both 'peer-to-peer' and/or 'star' network designs.
I've been scouting the Internet for potential solutions/ideas. There are plenty of options out there, but I can't seem to find the right one for me. Firstly, most MCU+Rx/Tx IC solutions don't come with enough GPIO ports. This makes it hard (if not impossible) for me to use any of the ATMEL's all-in-one options (such as the AT86RF212B) - especially for the base which needs at least 3 or 4 push buttons an LCD module, and a couple of relays. In my mind using a single-chip (MCU+Transceiver) solution would be beneficial for multiple reasons (heat, power consumption, PCB space, etc.), but I don't think there is anything available for my number of GPIO pins, correct?
For the sensor I could try to go with only an MCU + transmitter as it only has to capture data and send it back to the base (one-way communication). Has anyone designed something similar before?
Any ideas/suggestions are very much appreciated. Thanks much in advance.