Renesas SH7781 - Manual (Page 1166)

22. Serial I/O with FIFO (SIOF)
Rev.1.00 Jan. 10, 2008 Page 1136 of 1658
REJ09B0261-0100
(2) Control by Secondary FS (Slave Mode 2)
The CODEC normally outputs the SIOF_SYNC signal as synchronization pulse (FS). In this
method, the CODEC outputs the secondary FS specific to the control data transfer after 1/2 frame
time has been passed (not the normal FS output timing) to transmit or receive control data. This
method is valid for SIOF slave mode. The following summarizes the control data interface
procedure by the secondary FS.
• Transmit normal transmit data of LSB = 0 (the SIOF forcibly clears to 0).
• To execute control data transmission, send transmit data of LSB = 1 (the SIOF forcibly set to 1
by writing SITCDR).
• The CODEC outputs the secondary FS.
• The SIOF transmits or receives (stores in SIRCDR) control data (data specified by SITCDR)
synchronously with the secondary FS.
Figure 22.8 shows an example of the control data interface timing by the secondary FS.
TRMD[1:0] = 01, Specifications:
TDLE = 1,
RDLE = 1,
CD0E = 1,
REDG = 0
TDLA[3:0] = 0000,
RDLA[3:0] = 0000,
CD0A[3:0] = 0000, FL[3:0] = 1110 (Frame length: 128 bits),
TDRE = 0,
RDRE = 0,
CD1E = 0,
TDRA[3:0] = 0000,
RDRA[3:0] = 0000,
CD1A[3:0] = 0000,
SIOF_SCK
SIOF_RXD
SIOF_TXD
SIOF_SYNC
1 frame
L-channel
data
Control
channel 0
Slot No.0 Slot No.0
1/2 frame 1/2 frame
Secondary FS Normal FS Normal FS
LSB = 1 (Secondary FS request)
Figure 22.8 Control Data Interface (Secondary FS)