This section describes an example implementation of the auxiliary ASI mixer on the recording path. The following sample code was executed on a TAC5112EVM-K evaluation module using PurePath™ Console 3. Four input signals are provided to the device for the auxiliary ASI mixer:

• A 1kHz, 0.2Vrms differential analog sinusoidal signal on IN1P/IN1M.
• A 1 kHz, 0.5Vrms differential analog sinusoidal signal on IN2P/IN2M.
• A 500Hz, 0.5FS (Full-Scale) digital sinusoidal tone on PASI RX Channel 3.
• A 1.3kHz, 0.6FS (Full-Scale) PDM sinusoidal toneon PASI RX Channel 4.

Two analog input signals on the recording path, along with two digital input signals on the playback paths were used as inputs. The output of the mixer was sent on the DOUT of the Auxiliary ASI bus.

In this examples, both ASI buses were running at 48kHz, and hence the SRC was bypassed. The results are shown in Figure 2-5.

#FS refers to Full-Scale
w a0 00 00 #Page 0 
w a0 01 01 #SW Reset
d 01

w a0 00 00 #Page 0 
w a0 02 09 #Exit Sleep Mode with DREG and VREF Enabled
d 10

w a0 1a 30 #PASI in TDM protocol with 32-bit word length
w a0 4d 00 #VREF set to 2.75V for 2Vrms differential fullscale input
w a0 50 00 #ADC Channel 1 configured for AC-coupled differential input with 5kOhm input impedance and audio bandwidth
w a0 55 00 #ADC Channel 2 configured for AC-coupled differential input with 5kOhm input impedance and audio bandwidth

w a0 28 20 #Assign Slot 0 to RX CH1
w a0 29 21 #Assign Slot 1 to RX CH2
w a0 2a 22 #Assign Slot 2 to RX CH3
w a0 2b 23 #Assign Slot 3 to RX CH4

w a0 00 01 #Page 1
w a0 2c 30 #Enable ADC Channel Mixer, Loopback Mixer

#Default ADC Loopback mixer coefficients used
#ADC LB1 = ADC IN1 = 0.2Vrms, 1kHz analog signal (0.1FS)
#ADC LB2 = ADC IN2 = 0.5Vrms, 1kHz analog signal (0.25FS)
#DAC IN3 = 0.5FS, 500Hz signal (0.5FS)
#DAC IN4 = 0.6FS, 1.3kHz signal (0.6FS)

w a0 00 0b #Page 11
#Configure AUX Mixer for OUT1 = 0.3 * ADC LB1 + 0.7 * DAC IN3
w a0 30 2c cc cc cd #x = 0.7

#Configure AUX Mixer for OUT2 = 0.6 * ADC LB2 + 0.4 * DAC IN4
w a0 34 19 99 99 9a #x = 0.4

w a0 00 00 #Page 0
w a0 0a 10 #Configure GPIO1 as GPI
w a0 0b 10 #configure GPIO2 as GPI
w a0 0c 71 #Configure GPIO3 as SASI DOUT
w a0 11 94 #Configure GPIO1 as SASI FSYNC, GPIO2 as SASI BCLK
w a0 18 20 #Enable SASI; Same configurations as PASI

w a0 00 03 #Page 0
w a0 1e 20 #SASI Channel 1 is Channel 1 data
w a0 1f 21 #SASI Channel 2 is Channel 2 data

w a0 00 00 #Page 0
w a0 76 c3 #ADC Channels 1,2 and DAC Channels 3,4 enabled
w a0 78 c0 #ADC, DAC Powered Up