CMX649E3 CML Microcircuits, CMX649E3 Datasheet - Page 39

• Manufacturer Part Number: CMX649E3
• Description: ADM Codec
• Manufacturer: CML Microcircuits

ADM Codec
6.
6.1
C-BUS Operation
Instructions, status and data are transferred between the CMX649 and the host C over the C-BUS. The
C-BUS protocol complies with the CML C-BUS Hardware Interface specification. Instruction and data
transfers to and from the CMX649 consist of an Address/Command (A/C) byte followed by either:
The number of data bytes following an A/C byte is dependent on the value of the A/C byte. The most
significant bit of the address or data is sent first. The C-BUS SERIAL_CLOCK input to the CMX649
originates from the host µC.
2002 CML Microsystems Plc
SERIAL_CLOCK
REPLY_DATA
CMD_DATA
Application Notes
C-BUS Operation
CSN
Logic level is not important
MSB
Address/Command
7 6 5 4 3 2 1 0
1. a further instruction or
2. 1 or 2 bytes of data (write) or
3. 1 or 2 bytes of status or received data reply (read).
Byte
Figure 12 C-BUS Timing Diagram
LSB
First Reply Data Byte
MSB
7 6 5 4 3 2 1 0
7 6 5 4 3 2 1 0
39
First Data Byte
LSB
Last Reply Data Byte
7 6 5 4 3 2 1 0
7 6 5 4 3 2 1 0
Last Data Byte
CMX649
D/649/1