Motorola DSP56367 User Manual page 267

2. If the data word is right-aligned (TWA=1), and zero padding is disabled (PADC=0),
then the first data bit is repeated before the transmission of the data word. If zero
padding is enabled (PADC=1), zeroes are transmitted before the transmission of the
data word.
10.3.2.9 TCR Transmit Network Mode Control (TMOD1-TMOD0) - Bits 8-9
The TMOD1 and TMOD0 bits are used to define the network mode of ESAI transmitters
according to Table 10-4. In the normal mode, the frame rate divider determines the word
transfer rate – one word is transferred per frame sync during the frame sync time slot, as
shown in Figure 10-6. In network mode, it is possible to transfer a word for every time slot, as
shown in Figure 10-6. For more details, see Section 10.4, "Operating Modes".
In order to comply with AC-97 specifications, TSWS4-TSWS0 should be set to 00011 (20-bit
slot, 20-bit word length), TFSL and TFSR should be cleared, and TDC4-TDC0 should be set
to $0C (13 words in frame). If TMOD[1:0]=$11 and the above recommendations are
followed, the first slot and word will be 16 bits long, and the next 12 slots and words will be
20 bits long, as required by the AC97 protocol.
Table 10-4 Transmit Network Mode Selection
TMOD1
0
0
0
1
1
MOTOROLA
TMOD0 TDC4-TDC0
0 $0-$1F
1 $0
1 $1-$1F
0 X
1 $0C
DSP56367
Enhanced Serial Audio Interface (ESAI)
ESAI Programming Model
Transmitter Network Mode
Normal Mode
On-Demand Mode
Network Mode
Reserved
AC97
10-19