I would like to ask you some advice about ADS1220 here.
As we know, The ADS1220 is a precision, 24-bit, analog-to-digital converter (ADC) that offers many integrated features to reduce system cost and component count in applications measuring small sensor signals. The device features two differential or four single-ended inputs through a flexible input multiplexer (MUX), a low-noise, programmable gain amplifier (PGA), two programmable excitation current sources, a voltage reference, an oscillator, a low-side switch, and a precision temperature sensor . What’s more,The device can perform conversions at data rates up to 2000 samples-per-second (SPS) with single-cycle settling. At 20 SPS, the digital filter offers simultaneous 50-Hz and 60-Hz rejection for noisy industrial applications. The internal PGA offers gains up to 128 V/V. This PGA makes the ADS1220 ideally-suited for applications measuring small sensor signals, such as resistance temperature detectors (RTDs), thermocouples, thermistors, and resistive bridge sensors. The device supports measurements of pseudo- or fully-differential signals when using the PGA. Alternatively, the device can be configured to bypass the internal PGA while still providing high input impedance and gains up to 4 V/V, allowing for single-ended measurements.
At present, The MCU I used is freescale ZVH128 while spi is used to drive ADS1220. The buad rate of spi I set is 1M. The SPI outputted signal is normal as well as the SCK signal when I observe it by oscilloscope. But The return signal of ADS1220 can’t be read out. What troubles occurred? I have review it and read its data-sheet several times. I don’t know how to solve it.
Could anyone here help me? Thanks a million.
PS: I have linked the datasheet into ADS1220,please have a look if needed.