Writeback Trigger Transistor; Reset - Analog Devices EVAL-ADAU1701MINIZ Quick Start Manual

Table 4 shows the ADAU1701 pins connected to the different
GPIO functions and the associated settings.
Table 4. GPIO Setup
ADAU1701
Pin Device
MP1 Yellow LED D5
MP2 Push-button S4
MP3 Push-button S3
MP7 SSM2306 SD
MP8
10 kΩ
potentiometer
MP9 Push-button S6
MP10 Yellow LED D6
MP11 Red LED D4
When used in SigmaStudio, the input push-buttons appear as
shown in Figure 10.
Figure 10. Push-Button Inputs in SigmaStudio
When used in SigmaStudio, the output LEDs appear as shown
in Figure 11.
Figure 11. LED Outputs in SigmaStudio
SigmaStudio
Settings Setting
Active high Output GPIO
Push to Input GPIO
ground debounce,
invert
Push to Input GPIO
ground debounce,
invert
Active low Output GPIO
ADC3
Clockwise
turn lowers
resistance
Push to Input GPIO
ground debounce,
invert
Active high Output GPIO
Active high Output GPIO
Rev. 0 | Page 7 of 12
When used in SigmaStudio, the potentiometer input to the
auxilliary ADC appears as shown in Figure 12.
Figure 12. Potentiometer Input in SigmaStudio
The settings in the SigmaStudio register control window appear as
shown in Figure 13 when used with the EVAL-ADAU1701MINIZ.
Figure 13. SigmaStudio Multipurpose Pin Configuration for the
EVAL-ADAU1701MINIZ

WRITEBACK TRIGGER TRANSISTOR

The writeback trigger transistor circuit is intended to send a
high pulse to the ADAU1701 WB pin when the power supply
(DVDD) is interrupted. During normal operation, DVDD is
high (+5 V), so Transistor Q2 is always turned on, and the WB
signal is held low.
When the power supply (DVDD) is removed, the transistor
turns off, sending a high pulse on the WB signal line to the
ADAU1701. The two large 220 μF capacitors on the regulator
hold DVDD high until the data writeback transfer is complete,
thus providing adequate supply voltages to the ADAU1701 and
the self-boot EEPROM.

RESET

The ADM811 provides a clean active-low reset signal to the
ADAU1701 when Switch S2 is pressed.
EVAL-ADAU1701MINIZ