I have recently been trying to transition from Atmel's Atmega 328p avr to the newer (and much smaller) attiny416. The trouble is, the 416 only allows you to choose between two positive inputs and two negative inputs for the analog comparator, and I need only one positive but three negatives to multiplex between.
Because the input pins to the chip are fixed in hardware I couldn't think of much except to add an external multiplexer to the device which is not an option.
The ADC the chip has, however, can take input from almost every pin on the 20 pin chip. I have never worked with the ADCs on these chips, but they may hold the answer. Can an adc on an attiny be programmed to act as an analog comparator without the overhead of a digital conversion? I know at the core of ADCs are comparators but haven't found any grinchy tricks to use them in my solution (one positive input and three negatives to multiplex between).