High-Precision AD/DA Board User Manual
Contents
1. Pin Symbol Description 1 17 3 3V Power supply 3 3V 2 4 5V Power supply 5V 3 5 7 8 10 18 22 NC NC 24 26 27 28 29 32 36 38 40 6 9 14 20 25 30 GND Ground 34 39 11 DRDY ADS1256 data ready output low active 12 RESET ADS1256 reset input 13 PDWN ADS1256 sync power off input low active 15 cso ADS1256 chip select low active 16 cS1 DAC8552 chip select low active 19 DIN SPI data input 21 DOUT SPI data output 23 SCK SPI clock 31 33 35 37 GPIO extend to sensor interface Revision 1 1 Date July 17 2015 Author Zhou Jie Editor Felix High Precision AD DA User Manual 4 Revision history Wy WAVESHARE share awesome hardware Revision Changes Date 1 0 Initial release June 26 2015 1 1 Released English version manual July 17 2015 Minor edits Revision 1 1 Date July 17 2015 Author Zhou Jie Editor Felix2. AD input pinheaders the pinout is compatible with Waveshare sensor interface standard easy to connect various analog sensor modules 7 68M crystal LM285 2 5 provides reference voltage for the ADC chip Photo resistor LED output indicator 10K potentiometer DAC8552 16bit high precision DAC 2ch Power indicator ADS1256 24bit high precision ADC 8ch 4ch differential input ADC testing jumper DAC testing jumper Power selection jumper ADC reference ground configuration when AD single inputted the AINCOM is reference terminal can be connected to GND or external reference voltage Revision 1 1 Date July 17 2015 Author Zhou Jie Editor Felix High Precision AD DA User Manual Wy WAVESHARE share awesome hardware Symbol descriptions 1 2 3 4 5 6 7 8 AD DA input output Tab 2 ADO AD7 Analog input AGND Analog ground GND Digital ground VCC Power supply 3 3V and 5V optional can be switched by setting the Power selection jumper DAO DA1 Analog output Analog input Tab 3 ADO AD7 ADS1256 analog input DO D3 GPIO of ADS1256 See ADS1256 datasheet P22 P25 GPIO of Raspberry Pi AGND Analog ground LDR Light dependent resistor i e Photo resistor Tab 6 By connecting the jumper between AD1 and LDR the MCU can read the voltage output of LDR from the pin AD1 LEDA LEDB LED output indicator Tab 7 By connecting the jumper between LEDA LEDB and DACO DAC1 the volta
3. Set the Reference Input Voltage to 5V connect the pin 5V and VREF Set the Potentiometer output as an Analog Input connect the pin ADJ and ADO Make sure the left side Sensor Interface ADO is disconnected Set the LDR output as an Analog Input connect the pin LDR and AD1 Make sure the left side Sensor Interface AD1 is disconnected Connect AINCOM to AGND When using AD for differential measurements the common input AINCOM does not need to be tied to ground When using SSH for terminal control please connect the network cable The software PuTTY should be installed See the section 1 2 Power up Copy using a USB drive as acarrier the software directory ADS1256 to the Raspbian OS Note the system will detect the USB drive directly under GUI else if using SSH Connection the USB drive cannot be operated until it is mounted to the Linux Search the key words Linux mount for more details Make the files Enter the directory ADS1256 and execute make to compile it Execute sudo ads1256 test Note if it prompts command not found please use chmod x ads1256 test toadd execute permission Block the LDR from light and then the voltage of channel AD1 will be changed Turn the potentiometer and the voltage of channel ADO will be changed In the end press Ctrl C to suspend the current process Digital to analog conversion Connect the High Precision AD DA Board to the Raspberry Pi Revision 1 1 Date Jul
4. this operation a TF card reader is also required 4 Plug in the programmed TF card to the TF card socket on a Raspberry Pi and then power up to start the Raspbian OS System Configuration may be required for the first time boot up 1 2 How to use the terminal of Raspberry Pi All the supported software should run under the Linux terminal If you have a HDMI monitor just connect it to the Pi directly then open the terminal at the GUI If not you can operate the terminal of Pi using SSH 1 Connect the Pi and a router via a network cable 2 Run the software PuTTY on the PC connected to the router fill the IP address and Port of the Pi You can get the Pi s IP from the router And the Port is 22 by default 3 Connection type is set to SSH 4 Click the button Open to enter the Pi s terminal At the first boot up please input User name pi Password raspberry Revision 1 1 Date July 17 2015 Author Zhou Jie Editor Felix Wy WAVESHARE share awesome hardware High Precision AD DA User Manual 2 Getting started The following API source codes should be run under the bcm2835 library which can be downloaded from http www airspayce com mikem bcm2835 21 1 2 3 4 5 6 7 8 9 10 2 2 1 Analog to digital conversion Connect the High Precision AD DA Board to the Raspberry Pi Jumper settings Set the Power Supply to 5V connect the pin 5V and VCC
5. Wy WAVESHARE share awesome hardware High Precision AD DA User Manual High Precision AD DA Board User Manual There s no AD DA function on the Raspberry Pi GPIO interface this may troubled you in the Pi development However it won t be a problem anymore The High Precision AD DA Board allows you to add high precision AD DA functions to the Raspberry Pi Supported Pi Raspberry Pi 1 Model A Raspberry Pi 1 Model B Raspberry Pi 2 Model B Features Onboard ADS1256 8ch 24bit high precision ADC 4ch differential input 30ksps sampling rate Onboard DAC8552 2ch 16bit high precision DAC Onboard input interface via pinheaders for connecting analog signal E the pinout is compatible with Waveshare sensor interface standard easy to connect various analog sensor modules Onboard input output interface via screw terminals for connecting analog digital signal Features AD DA detect circuit easy for signal demonstration Revision 1 1 Date July 17 2015 Author Zhou Jie Editor Felix High Precision AD DA User Manual Wy WAVESHARE share awesome hardware What s on Board fOr 008 SD Oy Ue e 11 12 13 14 15 a EE N OOZ OC D 2 Alji ADO AGNO UCC GNO DACI DACO PUR LED oT PST aT TT TT High Precision AD DA Board wy amp SPP ZA FAT ZAP Ze AAAA SC E E K ae Raspberry Pi GPIO interface for connecting with the Pi AD DA input output screw terminals
6. ge output of DACO DAC1 can be estimated roughly by the brightness of LEDA LEDB ADJ The adjustable resistor of the 10K potentiometer Tab 8 By connecting the jumper between ADO and ADJ the MCU can read the voltage output of the potentiometer from the pin ADO PWR LED Power indicator Tab 10 Power selection jumper Tab 14 VCC Power supply selection VREF Reference input voltage 3V3 3 3V output 5V 5V output JMP_AGND Analog ground jumper Tab 15 For single ended measurements use AINCOM Analog input common as common input which can be connected to AGND or external reference voltage For differential measurements do not use AINCOM Revision 1 1 Date July 17 2015 Author Zhou Jie Editor Felix Wy WAVESHARE share awesome hardware High Precision AD DA User Manual 1 Basic operation of Raspberry Pi Before using the module with Raspberry Pi such basic operations are required Using Raspberry Pi image Using Linux Terminal If you have already known them please skip this section directly 1 1 How to use Raspberry Pi image 1 Download the Raspbian image from http www raspberrypi org downloads 2 Unzip the downloaded file and get an img file 3 Run the software Win32Disklmager exe then select the Image File the img file and Device The TF Card Reader click the button write to program the system image file Note The capability of TF card in used here should be more than 4GB In
7. y 17 2015 Author Zhou Jie Editor Felix 2 3 4 5 6 7 8 Wy WAVESHARE share awesome hardware High Precision AD DA User Manual Jumper settings Set the Power Supply to 5V connect the pin 5V and VCC Set the Reference Input Voltage to 5V connect the pin 5V and VREF Connect the pin DAO to LEDA the pin DA1 to LEDB Then the brightness of LEDA indicator will be changed according to the voltage output of DAO and the brightness of LEDB indicator will be changed according to the voltage output of DA1 When using SSH for terminal control please connect the network cable The software PuTTY should be installed See the section 1 2 Power up Copy using a USB drive as a carrier the software directory DAC8552 to the Raspbian OS Note the system will detect the USB drive directly under GUI else if using SSH Connection the USB drive cannot be operated until it is mounted to the Linux Search the key words Linux mount for more details Make the files Enter the directory DAC8552 and execute make to compile it Execute sudo dac8552 test Note if it prompts command not found please use chmod x dac8552 test toadd execute permission Expected result the brightness of LEDA and LEDB changes gradually Revision 1 1 Date July 17 2015 Author Zhou Jie Editor Felix High Precision AD DA User Manual 3 Interface Definition Wy WAVESHARE share awesome hardware
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