Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
9-10
Freescale Semiconductor
Enhanced Serial Audio Interface (ESAI, ESAI_1, ESAI_2, ESAI_3)
9.2.1.1
TCCR Transmit Prescale Modulus Select (TPM7–TPM0)—Bits 7–0
The TPM7–TPM0 bits specify the divide ratio of the prescale divider in the ESAI transmitter clock
generator. A divide ratio from 1 to 256 (TPM[7:0]=$00 to $FF) may be selected. The bit clock output is
available at the transmit serial bit clock (SCKT) pin of the DSP. The bit clock output is also available
internally for use as the bit clock to shift the transmit and receive shift registers. The ESAI transmit clock
generator functional diagram is shown in
.
Figure 9-3. ESAI Clock Generator Functional Block Diagram
FLAG0 OUT
(SYNC MODE)
FLAG0 IN
(SYNC MODE)
SCKR
SCKT
RCKD
TCKD
SYN=1
SYN=0
RCLOCK
TCLOCK
INTERNAL BIT CLOCK
SYN=1
RSWS4-RSWS0
TSWS4-TSWS0
RX WORD
LENGTH DIVIDER
TX WORD
LENGTH DIVIDER
RX SHIFT REGISTER
TX SHIFT REGISTER
DIVIDE
BY 2
PRESCALE
DIVIDE BY 1
OR
DIVIDE BY 8
DIVIDER
DIVIDE BY 1
TO DIVIDE BY
256
TPSR
TPM0–TPM7
RX WORD
CLOCK
TX WORD
CLOCK
SYN=0
DIVIDE
BY 2
PRESCALE
DIVIDE BY 1
OR
DIVIDE BY 8
DIVIDER
DIVIDE BY 1
TO DIVIDE BY
256
Fsys
RPSR
RPM0–RPM7
RHCKD=1
RHCKD=0
HCKR
RHCKD
DIVIDER
DIVIDE BY 1
TO DIVIDE BY
16
RFP0–RFP3
THCKD=1
THCKD=0
HCKT
THCKD
DIVIDER
DIVIDE BY 1
TO DIVIDE BY
16
TFP0–TFP3
INTERNAL BIT CLOCK
ERC0=1
SPDIF RCV
EXTAL
ERI0=1
ERI0=0
ERO0=0
ERO0=1
Fsys
EXTAL
ETI0=1
ETI0=0
EXTAL
ETO0=0
ETO0=1
Notes:
1. ETIx, ETOx, ERIx and EROx bit descriptions are covered in
Section 8.2.2.3, “Port H Data Register (PDRH)
2. Fsys is the DSP56300 Core internal clock frequency.
ERC0=0
EXTAL
To SPDIF Xmt