TLC320AD545 Datasheet, PDF (19/37 Pages) Texas Instruments – Single Channel Data/Fax Codec

DT_SCLK
DT_FS
DT_DIN D15 D14 D13 D12 _D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
DT_DOUT
D15 D14 D13 D12 _{D11 D10} D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Figure 4–3. FS Low Mode Primary Serial Communication Timing
4.2 Secondary Serial Communication
Secondary serial communication is used to read or write 16-bit words that program both the options and the circuit
configurations of the device. Register programming always occurs during secondary communication. Control
registers 1 and 2 can only be written to or read from the serial port. Two primary and secondary communication cycles
are necessary to program the control registers. If the default value for a particular register is desired, then the register
addressing can be omitted during secondary communications. The NOOP (no operation) command addresses a
pseudo-register, register 0, and no register programming takes place during this secondary communication.
During a secondary communication, a register may be written to or read from. When writing a value to a register, the
DT_DIN line contains the value to be written. The data returned on DT_DOUT is 00h.
The method for requesting a secondary communication is by asserting the least significant bit (D0) of DT_DIN high
as shown in Table 4–1.
Table 4–1. Least-Significant-Bit Control Function
CONTROL BIT D0
0
1
No secondary communication request
Secondary communication request
CONTROL BIT FUNCTION
Figure 4–4 shows the data format XX_DIN and XX_DOUT during secondary communication.
Don’t Care
D15
DT_DIN
(Read)
–– –– 1 D12 D11 D10 D9 D8
D7–D0
DT_DIN
(Write)
R/W
D15
Register Address
–– –– 0 D12 D11 D10 D9 D8
Register Data
D7–D0
AII 0
Register Data
DT_DOUT
(Read)
D15–D8
D7–D0
AII 0
DT_DOUT
(Write)
D15–D0
Figure 4–4. Secondary Communication DIN and DOUT Data Format
4–3