A 6502 or 8051 can do the job but their prices haven't dropped a lot. You can get a 48 MHz RISC-V from WCH (a big 8051 supplier) or Cortex-M0 from Puya for $0.

A 6502 or 8051 can do the job but their prices haven't dropped a lot. You can get a 48 MHz RISC-V from WCH (a big 8051 supplier) or Cortex-M0 from Puya for $0.10 to $0.15 depending on whether it's an 8, 16, or 20 pin package. Both the CH32V003 has 2 KB SRAM and 16 KB flash, and the Puya 3 KB SRAM and 20 KB flash. You get the above prices for the WCH at qty 50 (i.e. $5 - $7) on their Aliexpress store, plus a couple of bucks shipping. Being "too powerful" for the job is irrelevant if it's cheaper anyway. Plus easier to use because both use standard GCC/LLVM, support debugging etc.