83:Ports:14

Synopsis

Port Number: 14h

Function: Battery status checking

This is a read-only port indicating battery status. It also acts as a mirror of the link port on the rest of the bits.

Read Values

• Bit 0: Reads 1 if batteries are high; 0 if they are low.
• Bits 1 to 7: Mirror of the link port.

Comments

• The voltage level at which bit 0 flips depends on bits 6 and 7 of port 04.
• Bit 0 is directly connected to the reset circuit. That means that without bit 5 of port 04 set, the calculator will enter the reset state when bit 0 goes low.