U3600BM_05 Datasheet, PDF (7/44 Pages) ATMEL Corporation – Single-chip Cordless Telephone IC

U3600BM
3.7 Serial Bus Interface
The circuit is remoted by an external microcontroller through the serial bus.
The data is a 12-bit word:
A0 - A3: address of the destination register (0 to 15)
D7 - D0: contents of register
The data line must be stable when the clock is high and data must be serially shifted.
After 12 clock periods, the transfer to the destination register is (internally) generated by a low to
high transition of the data line when the clock is high.
Figure 3-1. Serial Bus
Micro-
processor
Data
D
Clock
C
Figure 3-2. Serial Bus Transmission
Data
(D)
D0 D1 D2
A0 A1 A2 A3
Clock
(C)
Figure 3-3. Serial Bus Structure
Data
Clock
1st word
Word transmission
4
0
Address
Decoder
15
4516D–CT0–10/05
2nd word
Transfer condition
8
128
Latches
Commands
7