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Not sure if the is a h/w or s/w issue but here goes- I'm using the MAX11040K to sample 9 channels (all microphones) which give a signal between 0 to 3.3V DC-biased by 1.65V; that's input to all channels for all 9 mics. I need to sample these at 20kHz simultaneously but I'm having trouble with my hardware: datasheet

I've daisy-chaining multiple devices as per the datasheet (figure 13 of the above link) and I can set the configuration register, though I can't get any sampled data out of the chain. Specifically, DRDYOUT never goes low, it's always high:

enter image description here

I'm unsure if I've interpreted the daisy-chain circuit correctly - I would've thought sharing a CS would case SPI bus contention with chips fighting to respond(?). However, when I set the config register I'm able to read back the correct setting. I'm sending this to the config register:

// Configure (configuration register)
/ command: write to configuration register => 0110 0000 = 0x60
// payload:
[![enter image description here][3]][3]

// Write to Configuration Register (0x60) → 0x2C = above config

uint8_t cfg_write[4] = {0x60, 0x2C, 0x2C, 0x2C};

// Step 1: Write config

HAL_GPIO_WritePin(CS_MAX_GPIO_Port, CS_MAX_Pin, GPIO_PIN_RESET);

HAL_SPI_Transmit(&hspi2, cfg_write, 4, HAL_MAX_DELAY);

HAL_GPIO_WritePin(CS_MAX_GPIO_Port, CS_MAX_Pin, GPIO_PIN_SET);

// Step 2. I'm reading back 0x2C from all three chips - which is a good sign and yet -

// step 3. Reading data Yet I'm not getting any sampled data, DRDYOUT remains high always.

Is this a hardware fault or a software issue, is there a missing step? If a hardware fault should I just scrap this and go for a another ADC using sample & hold IC's?

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  • Does single chip (no chaining) work? Commented May 17 at 20:13
  • Hi @dimich sadly no way of telling, all devices are interconnected on the pcb (in other words the PCB is the above sch) Is the hardware correct? Commented May 17 at 20:45
  • There is Multiple Device Connection chapter with diagram on p.25 in the datasheet. Commented May 17 at 21:16
  • yes, that's where I got my schematic from as I stated. I'm not familiar with this chip - is my hardware ok or have I made a mistake? I believe I've stayed as close to the stated figure 13 as possible. Commented May 17 at 21:34
  • That's machine learning algo, you can try python web scrapping for the same- medium.com/@manrajsinghglobal/… Commented Sep 9 at 14:40
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