"Backup Battery Very Low" sounds about right...pic.twitter.com/9GJxOI5MYu
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Sweet! Since the SA-1111 doesn't have an ADC, I guess a small external ADC is used to measure backup battery voltage
Close but not quite. There's an external processor cryptically referred to as the "MCU" which controls keyboard scanning, touch input, backlight PWM, and battery reading. I wouldn't be surprised if it's an *actual* MCU. Proper PCB pics with readable IC labels would help.