Hello, I have built custom board with TAS5721. Unfortunately I haven’t done any testing of the design before building actual PCB, and now I’m paying the price. Here’s the situation:
- For the application schematic, I have used „2.1 System” application example from the data sheet
- Circuit is getting all the necessary supplies: AVDD/DVDD 3.3V, PVDD 13V
- Circuit is drawing about 40mA summary from all power supplies
- Before any testing, i’m trying to do reset sequence (PDN low, RST high, PDN high, cycle RST low-high)
- I can’t get the chip to communicate over I2C. I’m using Raspberry Pi i2cdetect tool (PCB is an RPi hat) which basically transmits I2C packets with addresses from 0x0 to 0x77, and checks if SDA bus is pulled low, where acknowledgment from slave should be, during transmit of subsequent packets, and registers addresses that got the ack on SDA. TAS is not pulling SDA low neither on 0x34 or 0x36 (I have tried both pull up and pull down resistor on ADDR/FAULT pin), so it seems like i2C state machine inside the chip is not working properly (or at all). In result, i2detect doesn’t show anything on 0x34/0x36 addresses.
- I have checked I2C bus with oscilloscope - I2C transmission seems ok, SDA stays in fact high on both 0x34 an 0x36 packets where acknowledgment from slave should be - there is no response from TAS.
I need to start from minimal application which will get TAS5721 to communicate over I2C, and my question is: what are minimal necessary parts/signals in the application to get TAS5721 to respond on I2C? I’m guessing AVDD/DVDD/PVDD all are necessary, also RST/PDN from MCU to do a proper reset sequence. Which else external components/signals should be there for I2C bus to at least acknowledge an address packet sent to TAS? Is MLCK necessary? From the data sheet i understand that one can run TAS5721 entirely without MCLK present?
Thanks,
WM
