ADS7953: SPI not working manual mode

Dear Sir/Madam,

I have used ADS7953 ADC to read 16CH input of voltage range 0V to 5V.  VA+ = 5V, VBD = 3.3V , REFP = 2.5V  and REFM = 0V (GND). 

On board I have constant voltage source generating 4.096V (U10 in schematic) and connected to CH11 input of ADC. The host controller is RPI model 3B+.

The problem is on configuring the ADC to manual mode, I have to read CH11 to get 4.096V. But here I get 0 value on MISO line ( it is in tri-state even after pull up to 3.3V using 4.7KE). 

Schematic - 

ADS7953_Sch.pdf

Oscilloscope capture - (CH1 - MOSI - Yellow) (CH2 - MISO - BLUE) (CH3- SCK - PINK) (CH4 - CS# - GREEN)

IMAGE1 - shows only one frame

IMAGE2 - Shows 3 frames

IMAGE3 - Shows two frames in detail.

Program ADC program - 

def build_adc_command(mode, en_prog, next_channel, vref_change, operation, channel_gpio, gpio_dat):

    command = ((mode & 0x0F) << 12) | ((en_prog & 0x01) << 11) | ((next_channel & 0x0F) << 7) |\

              ((vref_change & 0x01) << 6) | ((operation & 0x01) << 5) | ((channel_gpio & 0x01) << 4) |\

              (gpio_dat & 0x0F)

    # print(command)

    return [((command >> 8) & 0xFF), (command & 0xFF)]



NUM_CH = 16



if __name__ == '__main__':

    adcValues = [0 for i in range(NUM_CH)]

    spi = spidev.SpiDev()

    spi.open(0, 1)

    spi.max_speed_hz = 1000000

    spi.mode = 0b11

    spi.cshigh = False

    spi.lsbfirst = False

    spi.bits_per_word = 8

    spi.no_cs = True

    GPIO.setmode(GPIO.BOARD)

    GPIO.cleanup()

    # setmode to input

    # setmode to output

    GPIOsetup(26, GPIO.OUT)

    reset = False



    while 1:

        try:

            time.sleep(0.25)  # 10 hz output

            # 0b00011101

            # 0b10000000

            # for ch in range(0, 7):

            # spi.xfer([0b00011101, 0b10000000])

            if reset is False:

                GPIO.output(26, GPIO.LOW)

                time.sleep(0.01)

                adcValues = spi.xfer2([0x42, 0x0f])

                time.sleep(0.001)

                GPIO.output(26, GPIO.HIGH)

                reset = True

            time.sleep(0.001)

            GPIO.output(26, GPIO.LOW)

            adcValues = spi.xfer2(build_adc_command(0b0001, 0b1, 0b1011, 0b1, 0b0, 0b1, 0b0000))

            print("xfer return Values 1 = ", adcValues)

            time.sleep(0.001)

            GPIO.output(26, GPIO.HIGH)

            time.sleep(0.001)

            GPIO.output(26, GPIO.LOW)

            adcValues = spi.xfer2(build_adc_command(0b0001, 0b1, 0b0001, 0b1, 0b0, 0b1, 0b1111))

            print("xfer return Values 2 = ", adcValues)

            time.sleep(0.001)

            GPIO.output(26, GPIO.HIGH)

            time.sleep(0.001)

            GPIO.output(26, GPIO.LOW)

            adcValues = spi.xfer2(build_adc_command(0b0001, 0b1, 0b0010, 0b1, 0b0, 0b1, 0b0000))

            print("xfer return Values 3 = ", adcValues)

            time.sleep(0.001)

            GPIO.output(26, GPIO.HIGH)

            time.sleep(0.001)

            GPIO.output(26, GPIO.LOW)

            adcValues = spi.xfer2(build_adc_command(0b0001, 0b1, 0b0011, 0b1, 0b0, 0b1, 0b1111))

            print("xfer return Values 4 = ", adcValues)

            time.sleep(0.001)

            GPIO.output(26, GPIO.HIGH)

        except KeyboardInterrupt:

            break

After going through above information, my problems are

1. ADC MISO pin always in tri-state even giving pull up.

2. Is the command sent are correct?

3. Not even junk data coming from MISO pin.

Kindly provide a solution at the earliest.