This is hopefully the last of my questions as I try to debug some issues with a custom board, a partial schematic of which is provided below (no, I didn't design the thing).
I noticed while running blink code that the delays were approximately 10X longer than specified. To further diagnose the issue, I had it report over Serial the milliseconds since start (millis()). I had included 100 ms on and 100 ms off in the code using delay(100). Thus, 15 on-off cycles should take 3,000 ms.
Millis() reported a cumulative time of ~3,000 ms. The actual elapsed time was 24 seconds!
Any thoughts on what could be so wildly wrong? I need to do some timekeeping in this project.