Data Transmission and Reception
11-27
Multichannel Buffered Serial Ports
Figure 11–9.Inter-IC Sound (IIS) Timing
D(R/X)
FS(R/X)
CLK(R/X)
Phase 1
Phase 2
FPER
FWID
B7
B6
B5
B2
B1
B0
C15
C14
C0
11.3.4.4 Frame Length: (R/X)FRLEN(1/2)
Frame length can be defined as the number of serial elements transferred per
frame. The length corresponds to the number of elements or logical time slots or
channels per frame synchronization signal. The 7-bit (R/X)FRLEN(1/2) field in the
(R/X)CR supports up to 128 elements per frame, as shown in Table 11–10.
(R/X)PHASE = 0 selects a single-phase data frame, and (R/X)PHASE = 1 selects
a dual-phase frame for the data stream. For a single-phase frame, the value of
FRLEN2 does not matter. Program the frame length fields with (
w minus 1),
where
w represents the number of elements per frame. For Figure 11–8,
(R/X)FRLEN1 = 1 or 0000001b and (R/X)FRLEN2 = 2 or 0000010b.
Table 11–10. McBSP Receive/Transmit Frame Length 1/2 Configuration
(R/X)PHASE
(R/X)FRLEN1
(R/X)FRLEN2
Frame Length
0
0
≤
n
≤
127
x
Single-phase frame; (n+1) words per frame
1
0
≤
n
≤
127
0
≤
m
≤
127
Dual-phase frame; (n+1) plus (m+1) words per frame