Thermistor Input, 3.3 A/D Converter Calibration | Digi RCM4000

B.4.3.2 Thermistor Input

Analog input LN7_IN on the Prototyping Board was designed specifically for use with a thermistor at JP25 in conjunction with the THERMISTOR.C sample program, which demon- strates how to use the analog input to measure temperature, which will be displayed in the Dynamic C STDIO window. The sample program is targeted specifically for the thermistor included with the Development Kit with R0 @ 25°C = 3 kΩ and β 25/85 = 3965. Be sure

to use the applicable R0 and β values for your thermistor if you use another thermistor.

		BVREF
		Inline jumper is
		10 kW resistor
		1 kW
	LN7_IN	ADC
		ADC
		(RCM4100)
		2.2 nF
		AGND
9		JP25
J3		Thermistor

Figure B-7. Prototyping Board Thermistor Input

B.4.3.3 A/D Converter Calibration

To get the best results form the A/D converter, it is necessary to calibrate each mode (single- ended or differential) for each of its gains. It is imperative that you calibrate each of the A/D converter inputs in the same manner as they are to be used in the application. For example, if you will be performing floating differential measurements or differential mea- surements using a common analog ground, then calibrate the A/D converter in the corre- sponding manner. The calibration must be done with the JP23/JP24 selection jumpers in the desired position (see Figure B-6). If a calibration is performed and a jumper is subse- quently moved, the corresponding input(s) must be recalibrated. The calibration table in software only holds calibration constants based on mode, channel, and gain. Other factors affecting the calibration must be taken into account by calibrating using the same mode and gain setup as in the intended use.

Sample programs are not yet available to illustrate how to read and calibrate the various A/D inputs for the three operating modes.

Mode	Read	Calibrate
Single-Ended, one channel	—	AD_CAL_CHAN.C

Single-Ended, all channels	AD_RDVOLT_ALL.C	AD_CAL_ALL.C

Differential, analog ground	AD_RDDIFF_CH.C	AD_CALDIFF_CH.C

102	RabbitCore RCM4000

Image 108

Digi RCM4000 user manual Thermistor Input, 3.3 A/D Converter Calibration, Mode Read Calibrate

Contents

RabbitCore RCM4000 Trademarks Rabbit Semiconductor Table of Contents Software Reference Appendix C. Power Supply 109 RabbitCore RCM4100 Introduction RCM4000 Features RCM4000 FeaturesFeature RCM4000 RCM4010 Advantages of the RCM4000 Development and Evaluation Tools 1 RCM4000 Development Kit Software Online Documentation RabbitCore RCM4000 Install Dynamic C Getting Started Hardware Connections Prepare the Prototyping Board for Development Attach Module to Prototyping Board Prototyping Board AC Adapter Connect Programming Cable Connect Power Troubleshooting Run a Sample ProgramRun a Sample Program Where Do I Go From Here? Technical Support RabbitCore RCM4000 Running Sample Programs Introduction Sample Programs User’s Manual Use of Nand Flash RCM4000 only Click OK or Close to exit the various dialog boxes Serial Communication User’s Manual 3 A/D Converter Inputs RCM4000 only Real-Time Clock Hardware Reference RabbitCore Module RCM4000 Digital Inputs and Outputs Shows the RCM4000 pinouts for header J3 4000 RCM4000 Pinout Configurations Pin Pin Name Default Use Alternate Use TXD PC0 PE1 Memory I/O Interface Other Inputs and Outputs Rabbit 4000 Serial Port and Clock Pins Serial CommunicationSerial Ports Ethernet Port RJ-45 Ethernet Port Pinout Programming Port Changing Between Program Mode and Run Mode Programming Cable Standalone Operation of the RCM4000 A/D Converter RCM4000 only Resistor Divider Network for Analog Inputs It is not referenced to 1 A/D Converter Power Supply Analog Supply Circuit Other Hardware Clock DoublerSpectrum Spreader Memory SramFlash Eprom Nand Flash RabbitCore RCM4000 Software Reference More About Dynamic C RabbitCore RCM4000 Dynamic C Function Calls Digital I/OSerial Communication Drivers Sram Use RabbitCore RCM4000 Prototyping Board Functions Board Initialization Void timedAlertunsigned long timeout Alerts ADS7870 Signal ADS7870 State RCM3400 Function/State Analog Inputs RCM4000 only On write operations Data value on read operations Unsigned int anaInDriverunsigned int cmd, unsigned int len Gain Code Multiplier AnaInConfig, anaIn, brdInit Single Diff Gain Code Multiplier Voltage Range ×10 ×16 ×20 126 Applies to Prototyping Board If successful If not able to make calibration constants Float anaInVoltsunsigned int channel, unsigned int gaincode Channel Code Single-Ended Voltage Range † Input Lines Float anaInDiffunsigned int channel, unsigned int gaincode Float anaInmAmpsunsigned int channel Channel Code 20 mA Input Lines Allchan Gain Code Voltage Range +AIN7 AIN6 Gain Code Voltage Range Upgrading Dynamic C Add-On Modules RabbitCore RCM4000 Using the TCP/IP Features TCP/IP Connections RabbitCore RCM4000 TCP/IP Primer on IP Addresses Typical Corporate Network IP Addresses Explained How IP Addresses are Used Dynamically Assigned Internet Addresses Placing Your Device on the Network Direct Connection Using a Hub Running TCP/IP Sample ProgramsDirect Connection How to Set IP Addresses in the Sample Programs How to Set Up your Computer for Direct Connect Direct Connection PC to RCM4000 Module Run the PINGME.C Sample Program Running Additional Sample Programs With Direct Connect Where Do I Go From Here? RabbitCore RCM4000 Appendix A. RCM4000 Specifications Electrical and Mechanical Characteristics Dia × Exclusion Zone Table A-1. RCM4000 Specifications Parameter RCM4000 RCM4010 Ten 8-bit timers 6 cascadable from the first Table A-2 Converter Specifications 1 A/D ConverterParameter Test Conditions Headers Figure A-3. User Board Footprint for RCM4000 Rabbit 4000 DC Characteristics Table A-4 .3 Volt DC CharacteristicsSymbol Parameter Maximum Rating Symbol Parameter Min Typ Max I/O Buffer Sourcing and Sinking Limit Bus LoadingTable A-5. Capacitance of Rabbit 4000 I/O Ports Table A-6. External Capacitive Bus Loading -40C to +85C Iord Table A-8. Preliminary Data and Clock Delays Output Delay30 pF 60 pF 90 pF Ns setting No dbl / dbl Clock to Address Worst-Case Conformal Coating Conformally coated Area Jumper Configurations Table A-9. RCM4000 Jumper ConfigurationsHeader Description Pins Connected Factory Default RabbitCore RCM4000 Appendix B. Prototyping Board Current Measurement Headers RCM4000 Prototyping Board Features RabbitCore RCM4000 Mechanical Dimensions and Layout 935 Power Supply Table B-1. Prototyping Board SpecificationsParameter Specification Using the Prototyping Board Signals Pin Pin Name Prototyping Board Use Adding Other Components Measuring Current Draw Analog Features RCM4000 only Table B-3. Positive A/D Converter Input Voltage Ranges3.1 A/D Converter Inputs Table B-4. Differential Voltage Ranges Mode Read Calibrate Thermistor Input3.3 A/D Converter Calibration Table B-5. Prototyping Board Serial Port Configurations Serial Port Header Default Use Alternate Use 4.1 RS-232 Prototyping Board Jumper Configurations Table B-6. RCM3400 Prototyping Board Jumper Configurations JP5 LN4IN-LN6IN 108 Appendix C. Power Supply Power SuppliesBattery-Backup Circuits Reset Generator 165 mA·h = 2.5 years User’s Manual 111 112 Index SMODE0 SMODE1 ADCALALL.C User’s Manual 115 116 Schematics