The AD7887 is a high speed, low power, 12-bit analog-to-digital converter (ADC) that operates from a single 2.7 V to 5.25 V power supply. The AD7887 is capable of 125 kSPS throughput rate. The input track-and-hold acquires a signal in 500 ns and features a single-ended sampling scheme. The output coding for the AD7887 is straight binary, and the part is capable of converting full power signals of up to 2.5 MHz.
The AD7887 can be configured for either dual- or single-channel operation via the on-chip control register. There is a default single-channel mode that allows the AD7887 to be operated as a read-only ADC. In single-channel operation, there is one analog input (AIN0) and the AIN1/VREF pin assumes its VREF function. This VREF pin allows the user access to the part’s internal 2.5 V reference, or the VREF pin can be overdriven by an external reference to provide the reference voltage for the part. This external reference voltage has a range of 2.5 V to VDD. The analog input range on AIN0 is 0 to VREF.
The goal of this project (Microcontroller No-OS) is to be able to provide reference projects for lower end processors, which can't run Linux, or aren't running a specific operating system, to help those customers using microcontrollers with ADI parts. Here you can find a generic driver which can be used as a base for any microcontroller platform and also specific drivers for Renesas platforms.
The driver contains two parts:
The Communication Driver has a standard interface, so the AD7887 driver can be used exactly as it is provided.
There are three functions which are called by the AD7887 driver:
SPI driver architecture
The following functions are implemented in this version of AD7887 driver:
|unsigned char AD7887_Init(void)||Initializes the AD7887 device.|
|unsigned short AD7887_Read(unsigned char config)||Perform a read operation from the AD7887.|
This section contains a description of the steps required to run the AD7887 demonstration project on a Renesas RX63N platform.
An EVAL-CN0150A-SDPZ has to be interfaced with the Renesas Demonstration Kit (RDK) for RX63N:
EVAL-CN0150A-SDPZ testpoint TP13 (CS) → YRDKRX63N J15 connector Pin 1 EVAL-CN0150A-SDPZ testpoint TP12 (MOSI) → YRDKRX63N J15 connector Pin 2 EVAL-CN0150A-SDPZ testpoint TP11 (MISO) → YRDKRX63N J15 connector Pin 3 EVAL-CN0150A-SDPZ testpoint TP10 (SCLK) → YRDKRX63N J15 connector Pin 4 EVAL-CN0150A-SDPZ testpoint TP7 (GND) → YRDKRX63N J15 connector Pin 5
This section presents the steps for developing a software application that will run on the Renesas Demo Kit for RX63N for controlling and monitoring the operation of the ADI part.