CM1K Hardware User’s Manual
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Remark:
If the reco_logic is running, sending an I2C request might not fit within the ~B_BSY time frame which
starts at the fall of V_FV and finishes at the rise of CAT_VAL. The RTDIST and RTCAT registers can be read at any
time over the I2C bus because their access does not require any interruption of CM1K parallel bus, but any other
command must be submitted carefully when B_BSY is low and RDY is high.
5.4
I2C transmission codes
5.4.1
Bus Idle State
The bus is idle when both the data and clock lines are HIGH. Control of the bus is initiated
with a start bit, and the bus is released with a stop bit. Only the master can generate the start and stop bits.
5.4.2
Start Bit
The start bit is defined as a HIGH-to-LOW transition of the data line while the clock line is HIGH.
5.4.3
Stop Bit
The stop bit is defined as a LOW-to-HIGH transition of the data line while the clock line is HIGH.
5.4.4
Acknowledge Bit
The master generates the acknowledge clock pulse. The transmitter (which is the master when writing, or the slave
when reading) releases the data line, and the receiver indicates
an acknowledge bit by pulling the data line low during the acknowledge clock pulse.
5.4.5
No-Acknowledge Bit
The no-acknowledge bit is generated when the data line is not pulled down by the receiver during the
acknowledge clock pulse. A no-acknowledge bit is used to terminate a read sequence.