The command
format is viewed from the CCSI peripheral side. Figure 7-2 defines the format of the command transmission. There are three
states in one command:
- IDLE: CLK_O is always
active and continuous. SIN is always HIGH.
- START: SIN changes
from HIGH to LOW after the IDLE state.
- DATA:
- Head_byte: The
command identifier, contains one 16-bit data and one check bit.
- Data_bytes_N-1: Each data-byte contains 3 × 17-bit data,
each 17-bit data contains one 16-bit data word and one check
bit.
- END: The device
recognizes continuous 18-bit HIGH on SIN, and then returns to IDLE
state.
- CHECK BIT: The check
bit (17th bit) value is the NOT of 16th bit
value to avoid continuous 18-bit HIGH (to distinguish with END).
The IDLE state is not necessary, which means the START state of the next
command can connect to the END state of the current command.