LTC2314-14 not working

LTC2314-14 is not working. Only zeros coming on SPI. I am using STM32L431RBT6 as SPI master at 8MHz.

I used the following code:

HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_RESET); // CHIP SELECT PIN 
HAL_Delay(5);

HAL_SPI_Receive(&hspi1,(uint8_t *)&buf,2,10);
HAL_Delay(5);


HAL_UART_Transmit(&huart1,buf,2,5);
HAL_Delay(100);


HAL_GPIO_WritePin(GPIOA,GPIO_PIN_4,GPIO_PIN_SET);
HAL_Delay(5);

Parents Reply
  • Please find the attached schematic and oscilloscope waveform .

    Schematic: SDO , SCK and NCS are going to microcontroller. AIN is given REF (2.048V) but the output is coming 0.                     I am sending the output over UART at 19200 Baud rate.

    Waveform: Blue waveform is NCS.

                       Yellow waveform is SCK 

                        No signal is coming on SDO.

Children
  • 0
    •  Analog Employees 
    on Aug 13, 2019 2:14 PM over 1 year ago in reply to akashk

    NCS should not go high and then low in between the two groups of 8 SCK pulses.

    Please provide a waveform for SDO.

    There is 1 cycle of latency on this part, so the first conversion result will always be garbage. If multiple conversions are done, do all conversion results provide all zeros?

    The waveforms on the scope photo appear to have lots of ringing. This could be because of poor oscilloscope probe grounding or it could mean that your setup is not clean. Do you have a ground plane for your PCB? Are your bypass caps located right next to the VDD and REF pins? Can you provide a photo of your setup?

    What is providing the 3V for Vdd and OVdd? Is it a switching power supply? Please provide a scope photo showing what the output of the 3V supply looks like.