Datasheet
AD73311
–29–
REV. B
APPENDIX B
Programming a Single AD73311 for Mixed Mode Operation
This section describes a typical sequence in programming a
single codec to operate in mixed mode. The device is connected
in Nonframe Sync Loop-Back Mode (see Figure 14), which
allows the DSP’s Tx Reg to determine how many words are sent
to the device. In Step 1, the part has just been reset and on the
first output event the codec presents an invalid output word
1
.
The DSP’s Tx Reg contains a control word that programs CRA
with the data word 0x03, which will put the device in mixed
mode. In Step 2, the control word from the DSP’s Tx Reg has
been sent to the codec’s SPORT and the output word has been
received by the DSP’s Rx Reg. The Tx Register raises the
SDIFS to send a control word that will program CRB of the
codec. In Step 3 the SCLK and sample rate are set by program-
ming CRB. In Step 4, the analog sections of the device are
powered up by programming CRC, while in Step 5, the encoder
gain is set to 0 dB via CRD. In Step 6, the DAC register is
updated by the contents of the serial register. Alternately, a
register read cycle could be introduced instead of the DAC load
in Step 6
2
. Steps 7 and 8 show another ADC read, DAC write
cycle.
NOTES
1
Data output by the codec in program mode is invalid and should not be inter-
preted as ADC data. The only exception to this is output caused by register
reads or CEE being enabled on control word writes.
2
In mixed mode, it may be necessary to terminate a control word write to a
device with a control word read to that device in order to ensure that the next
ADC sample is correct. Alternatively the ADC word can either be discarded or,
if this is not possible, it can be rebuilt by incrementing the “address field”
within the 16-bit word.
DSP TX REG
CONTROL WORD 1
1 0 000 000 00000011
ADC WORD 1 *
0000 0000 0000 0000
DON'T CARE
XXXX XXXX XXXX XXXX
STEP 1
DSP TX REG
DEVICE 1
CONTROL WORD 1
1 0 000 001 00001111
CONTROL WORD 1
1 0 000 000 00000011
ADC WORD 1 *
0000 0000 0000 0000
DSP RX REG
STEP 2
DSP TX REG
DEVICE 1
CONTROL WORD 1
1 0 000 010 00000001
CONTROL WORD 1
1 0 000 001 00001111
DON'T CARE
XXXX XXXX XXXX XXXX
DSP RX REG
STEP 3
DSP TX REG
DEVICE 1
CONTROL WORD 1
1 0 000 000 00000001
CONTROL WORD 1
1 0 000 010 00000001
DON'T CARE
XXXX XXXX XXXX XXXX
DSP RX REG
STEP 4
DSP TX REG
DEVICE 1
DAC WORD 1
0100 0000 0000 0000
CONTROL WORD 1
1 0 000 011 00100000
DON'T CARE
XXXX XXXX XXXX XXXX
DSP RX REG
STEP 5
DSP TX REG
DEVICE 1
DAC WORD 1
0011 1111 1111 1111
DAC WORD 1
0100 0000 0000 0000
DON'T CARE
XXXX XXXX XXXX XXXX
DSP RX REG
STEP 6
DSP TX REG
DAC WORD 1
0011 1111 1111 1111
ADC WORD 1
0100 0000 0000 0000
DON'T CARE
XXXX XXXX XXXX XXXX
DSP RX REG
STEP 7
DSP TX REG DEVICE 1
DAC WORD 1
0100 0000 0000 0000
DAC WORD 1
0011 1111 1111 1111
ADC WORD 1
1000 0000 0000 0000
DSP RX REG
STEP 8
*ADC SAMPLES DURING PROGRAM MODE ARE INVALID.
DEVICE 1
DSP RX REG
DEVICE 1
Figure 34. Programming a Single AD73311 for Mixed Mode