ICS1493-17
CLOCK SYNTHESIZER FOR PORTABLE SYSTEMS SYNTHESIZERS
IDT™ / ICS™
CLOCK SYNTHESIZER FOR PORTABLE SYSTEMS 7
ICS1493-17 REV A 101005
Serial Data Interface
Data Protocol
The clock driver serial protocol accepts byte write, byte read, block write, and block read operations from the
controller. For block write/read operation, the bytes must be accessed in sequential order from lowest to highest
byte (most significant bit first) with the ability to stop after any complete byte has been transferred. For byte write
and byte read operations, the system controller can access individually indexed bytes. The offset of the indexed
byte is encoded in the command code, as described in the following table.
The block write and block read protocol is outlined in the table below, followed by the corresponding byte write and
byte read protocol. The slave receiver address is 11010010 (D2h).
Bit Description
7 0 = Block read or block write operation, 1 = Byte read or byte write operation
(6:0) Byte offset for byte read or byte write operation. For block read or block write operations,
these bits should be '0000000'.
Block Write Protocol Block Read Protocol
Bit Description Bit Description
1 Start 1 Start
2:8 Slave address - 7 bits 2:8 Slave address - 7 bits
9 Write = 0 9 Write = 0
10 Acknowledge from slave 10 Acknowledge from slave
11:18 Command code — 8 bit
‘00000000’ stands for block operation
11:18 Command code - 8 bit
‘00000000’ stands for block operation
19 Acknowledge from slave 19 Acknowledge from slave
20:27 Byte count — 8 bits 20 Repeat start
28 Acknowledge from slave 21:27 Slave address — 7 bits
29:36 Data byte 0 — 8 bits 28 Read = 1
37 Acknowledge from slave 29 Acknowledge from slave
38:45 Data byte 1 — 8 bits 30:37 Byte count from slave — 8 bits
46 Acknowledge from slave 38 Acknowledge from master
.... ............................. 39:46 Data byte from slave — 8 bits
.... Data byte (N-1) — 8 bits 47 Acknowledge from master
.... Acknowledge from slave 48:55 Data byte from slave — 8 bits
.... Data byte N — 8 bits 56 Acknowledge from master
.... Acknowledge from slave .... Data byte N from slave — 8 bits
.... Stop .... Not Acknowledge from master
.... Stop
