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#### 9.2.2.5 CIA module

The CIA 6526 is an I/O port chip with 2 8-bit I/O ports, a shift register, two timers, a Time of Day clock and interrupts.

Version numbers: Major 1, Minor 1.

Type | Name | Description
BYTE | ORA | Output register A
BYTE | ORB | Output register B
BYTE | DDRA | Data direction register A
BYTE | DDRB | Data direction register B
WORD | TAC | Timer A counter value
WORD | TBC | Timer B counter value
BYTE | TOD_TEN | Time of Day - current tenth of second
BYTE | TOD_SEC | Time of Day - current seconds
BYTE | TOD_MIN | Time of Day - current minutes
BYTE | TOD_HR | Time of Day - current hours
BYTE | SDR | contents of shift register
BYTE | IER | mask of enabled interrupt masks
BYTE | CRA | Control register A
BYTE | CRB | Control register B
WORD | TAL | Timer A latch value
WORD | TBL | Timer B latch value
BYTE | IFR | mask of currently active interrupts
BYTE | PBSTATE | Bit 6/7 reflect the PB6/7 toggle bit state. Bit 2/3 reflect the corresponding port bit state.
BYTE | SRHBITS | number of half-bits to still shift in/out SDR
BYTE | ALARM_TEN | Time of Day - alarm tenth of second
BYTE | ALARM_SEC | Time of Day - alarm seconds
BYTE | ALARM_MIN | Time of Day - alarm minutes
BYTE | ALARM_HR | Time of Day - alarm hours
BYTE | READICR | current clock minus the clock when ICR was read last plus 128.
BYTE | TODLATCHED | Bit 0: 1= latched for reading, Bit 1: 2=stopped for writing
BYTE | TODL_TEN | Time of Day - latched tenth of second
BYTE | TODL_SEC | Time of Day - latched seconds
BYTE | TODL_MIN | Time of Day - latched minutes
BYTE | TODL_HR | Time of Day - latched hours
DWORD | TOD_TICKS | clk ticks till next tenth of second
– | – | The next items have been added in V1.1
WORD | TASTATE | The state bits of the CIA timer A, according to ciatimer.h
WORD | TBSTATE | The state bits of the CIA timer B, according to ciatimer.h

The last two items have been added in CIA snapshot version 1.1 due to the improved CIA emulation in the newer VICE versions. Some state bits correspond to the CIA state as described in the "A Software Model of the CIA 6526" document by Wolfgang Lorenz, some are delayed versions. For more read the source file `ciatimer.h`.

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