Background: I am familiar with interfacing a few incremental/quadrature encoders to a single MCU chip. My go-to chip
STM32F10x can decode 4-5 encoders even in a LQFP64 package (e.g.
STM32F100R8T6 has 4), which had always been more than enough for me... until now.
Problem: I want an
ATXMEGA128 to effectively poll counts of all 30 encoders at 1kHz (say, by keeping 16-bit counters). I cannot change the
ATXMEGA128 to some other MCU, but I can add another MCU to interface with it.
The bottom line is I could slap on a FPGA (e.g. Spartan3E) and make it talk to MCU through SPI or parallel, but I'd like to consider some alternatives before I go down this path (for non-technical reasons). The number can be reduced to 15 if 30 seems too hard without FPGA.