The ADS125P08 EVM is designed for easy connection to an external controller. This design enables the user to test application code and firmware on the ADS125P08 without having to develop a custom PCB. This section describes the specific connections required to use the ADS125P08 EVM with an external controller. Figure 2-7 shows the location of various headers, connectors, and terminal blocks described in this section.
Complete the following steps to prepare the ADS125P08 EVM for use with an
external controller:
- Remove the PHI board if still connected to the
EVM
- Connect the external controller ground and bench
supply ground to the GND pins on the EVM
- Connect an external bench supply to the ADC AVDD pin by performing only one
of the following two options:
- Remove the shunt on JP2
and apply 5.5V to the “LDO_IN” pin on JP2
- Remove the shunt on JP3
and apply the AVDD voltage to the “AVDD” pin on JP3
- Connect an external bench supply to the ADC IOVDD
pin by removing the shunt on JP1 and applying the IOVDD voltage to the “IOVDD”
pin on JP1
- Apply digital communication signals to header J4
on the EVM:
- Connect POCI (peripheral out, controller in) from
the controller to the SDO pin
- Connect PICO (peripheral in, controller out) from
the controller to the SDI pin
- Connect SCLK from the controller to the SCLK
pin
- Connect CS from the controller
to the CS pin
- Connect an I/O pin from the controller to the
DRDY pin. DRDY is an
output from the ADC that indicates when new data are ready to be clocked
out of the ADC. Write a user-defined data collection routine that
monitors this pin (polling or interrupt) and only transfers data after a
falling edge
- (Optional) Connect I/O pins from the controller to
the START and RESET pins to control conversions and
reset the device, respectively
- (Optional) Connect an external Section 2.6 or Section 2.5
- Connect the signal source to the terminal
blocks
Verify that the external power supply voltages,
communication signal levels, and applied input signals meet the specifications
listed in Table 1-1