Hi,
I am trying to implement the AD5672R chip on a test bench (TSSOP).
I use the Arduino Mega as the controller (MSBFirst, SPI_MODE1, and 100kHz).
I try to use the 8 Vout of the chip, between 0 and 5 V.
Pins config:
- Vdd = Vlogic = GAIN = RSTSEL 5V (from arduino).
- LDAC to GND
- GND to arduino GND
- SYNC/SCLK/SDI/SDO to arduino pins 53/52/51/50
Two 0.1 and 10 µF capacitors are set between the 5V and GND.
I use this function to write value (12 bits) to a given channel (4 bits):
digitalWrite(CHIPSELECT, LOW); delayMicroseconds(3); SPI.transfer(0x30 | (channel & 0x0F)); // Commande pour écrire sur le DAC SPI.transfer((value >> 4) & 0xFF); // 8 Bits de poids fort SPI.transfer((value << 4) & 0xF0); // 4 Bits de poids faible delayMicroseconds(3); digitalWrite(CHIPSELECT, HIGH);Nothing happens, all outputs stay to 0V.
If my understanding is good, since I linked RSTSEL and GAIN to Vlogic, all output channels should be at 2.5 V. This is not the case.
Am I missing something?
I also tried to reset by software the chip with the 0x60 commande followed by 0x1234, but nothing changes.
I tried to setup the readback with 0x90 followed by 0x0000, then sending a 0x0000 to receive the bits but I get nothing.
I used a logic analyser to be sure that the arduino is sending the data, and it seems legits. You can find the screenshots below.
At this point, with no signals coming from SDO, and 0V at every Vout, I wonder if the chip is even alive. But Vref is displaying 2.5 V, so something is alive inside.
How can I be sure that the chip is functionnal? What am I doing wrong?
Any help would be very very welcome.
Thank you
Pierre
Writing to DAC0:
Asking for readback DAC0:
Trying to readback DAC0:
Trying to reset the chip:
