4–4

Figure 4–4. Secondary Communication DIN and DOUT Data Format

4.4

FS High Mode Secondary Communication Timing

On the rising edge of DT_SCLK, coinciding with the falling edge of FS, D15–D0 is input serially to DT_DIN and

D15–D0 is output serially on DT_DOUT. If a secondary communication request is made, FS goes high again, 128

SCLKs after the beginning of the primary frame, to signal the beginning of the secondary frame one SCLK period later.

See Figure 4–5.

DT_DIN

Data (D0=1)

Register R/W

Data (D0=0)

DT_FS

P

SPP

Secondary Communication

Request

No Secondary

Communication Request

128 DT_SCLKs

Figure 4–5. FS Output During Software Secondary Serial Communication Request

(FS High Mode)

4.5

FS Low Mode Secondary Communication Timing

On the falling edge of FS for that channel, D15–D0 is input serially to DT_DIN and D15–D0 is output serially on

DT_DOUT. FS remains low during the data transfer and then returns high. If a secondary communication request is

made, FS goes low 128 SCLKs after the beginning of the primary frame to signal the beginning of the secondary

frame. See Figure 4–6.

Data (D0=1)

Register R/W

Data (D0=0)

PSP

Secondary Communication

Request

No Secondary

Communication Request

128 DT_SCLKs

DT_DIN

DT_FS

Figure 4–6. FS Output During Software Secondary Serial Communication Request

(FS Low Mode)