Calibration of the ADC, Calibrat.Asm | Texas Instruments TLV1562

8.6.3Calibration of the ADC

Software Overview

8.6.3Calibration of the ADC

CALIBRAT.ASM

**************************************************************************

* TITLE	: TLV1562 ADC Interface routine	*
* FILE	: CALIBRAT.ASM	*
* FUNCTION	: CALIBRAT_INTERNAL_MID_SCALE	*
*	CALIBRAT_SYSTEM_MID_SCALE	*
* CALLS	: N/A	*
* PRECONDITION	: N/A	*
* POSTCONDITION	: N/A	*
* SPECIAL COND.	: N/A	*
* DESCRIPTION	: routine to perform a ADC calibration	*
* AUTHOR	: AAP Application Group, ICKE, Dallas	*
*	CREATED 1998(C) BY TEXAS INSTRUMENTS INCORPORATED.	*
* REFERENCE	: TMS320C54x User’s Guide, TI 1997	*

**************************************************************************

.title	”CALIBRAT”
.mmregs
.width	80
.length	55

.version 542

.if (IME_CALIBRATIONSME_CALIBRATION)

.sect ”.data”

CR_CALIBRA .usect ”.variabl”, 1 ; temporary variable, can be changed anywhere during the program

.sect ”.text”

.if (IME_CALIBRATION)

************************************************************************************

*CALIBRAT_INTERNAL_MID_SCALE

*performs an internal calibration of the ADC to offset for internal device errors

*basic idea: do a error calibration in mono interrupt driven mode using CSTART

*for conversion but use the channel & single/differential input information already

*set-up in the CR0_send register from

************************************************************************************

CALIBRAT_INTERNAL_MID_SCALE:

DP	= #AD_DP	; initialize data pointer
* clear calibration related bits in CR0:
@CR0_SEND &= #(NO_CALIB_OP^0FFFFh)		; clear bit for no calibration use
@CR0_SEND &= #(CALIB_OP^0FFFFh)		; clear bit for no calibration use

*initialize the send values to setup the two programmable registers of the ADC to calibrate

data(CR_CALIBRA) = @CR0_SEND ; load help register with CR0 content

*use calibrated mode in the following for conversion

@CR0_SEND = #CALIB_OP

; set calibration for further use

Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP

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Image 59

Texas Instruments TLV1562 manual Calibration of the ADC, Calibrat.Asm, Software Overview

Contents

TParalInteMS3rflelADConvertertotheacing20C54xDSPtheTLV1562 JulySLAA040 Application Report IMPORTANT NOTICE Contents 8.5.5 Figures List of FiguresList of Tables viSLAA040 2.1 TMS320C54x Starter Kit Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP1 Introduction 2 The Board 2.3.1.1 The Universal Interface 2.2 TLV1562EVM2.3 ADC TLV1562 Overview 2.3.1 Suggestions for the ’C54x to TLV1562 Interface Figure 2. TLV1562 to ’C54x DSP Interface of the EVM Using RD or the CSTART Signal to Start Conversion2.3.2 Recyclic Architecture 2.4.1 TLC5618A - Serial DAC 2.3.3 Note on the Interface, Using an External ADC Clock Drive2.4 Onboard Components Figure 4. THS5651 to C542 DSP Interface 2.4.2 THS5651 - Parallel Output CommsDACFigure 3. TLC5618A to ’C542 DSP Interface 3.2 Input Data Bits 3 Operational Overview3.1 Reference Voltage Inputs 3.3 Connections Between the DSP and the EVM Table 1. Signal Connections 8SLAA040 3.3.1 Jumpers Used on the TLV1562EVMTable 2. 3-Position Jumpers Table 3. 2-Position Jumpers Table 4. DSP/DAC Interconnection 4 The Serial DAC/DSP System 5 The DSP Serial Port Table 5. DSP Serial Port Signals and Registers 6.1 DSP Internal Serial Port Operation 6 Other DSP/TLV1562 Signals Table 6. DSP Algorithm for Writing to the ADC 7.2 Mono Interrupt Driven Mode Using RD7 Conversation Between the TLV1562 and the DSP 7.1 Writing to the ADC tENDATAOUT = 41 ns Table 7. DSP Algorithm for Mono Interrupt Driven Mode Using RDtDCSL-sample+1ADCSYSCLK 14 SLAA040 7.3 Mono Interrupt Driven Mode Using CSTARTTable 8. DSP Algorithm for Mono Interrupt Driven Mode Using CSTART Table 9. DSP Algorithm for Dual Interrupt Driven Mode 7.4 Dual Interrupt Driven Mode 16 SLAA040 7.5 Mono Continuous ModeTable 10. DSP Algorithm for Mono Continuous Mode Table 11. DSP Algorithm for Dual Continuous Mode 7.6 Dual Continuous Mode 8.2 DSP Memory Map 8 Software Overview8.1 Software Development tools Figure 5. Memory Map 8.3.2 Address and Data Bus for I/O Tasks 8.3.3 Timer Output8.3 Programming Strategies for the ’C54x, Explanations 8.3.1 Optimizing CPU Resources for Maximum Data Rates 8.3.6 Interfacing the Serial DAC 5618A to the DSP 8.3.5 Generating the Chip Select Signal and the CSTART Signal8.3.4 Data Page Pointer MARK DP = #1 ARP = #5 8.3.7 Interrupt Latency8.3.8 Branch Optimization goto/dgoto, call/dcall GOTO MARK 8.4.1 Software Principals of the Interface 8.3.9 Enabling Software Modules .if/.elseif/.endif8.4 Software Code Explanation Disadvantage 8.4.1.2 Timed Solution8.4.1.1 Software Polling Advantage Disadvantages 8.4.1.3 Interrupt Driven Solution8.4.1.5 Setting the Right Switches Advantages Table 13. Instruction in the Program Header Step Table 12. Switch SettingsTask 8.4.1.6 Common Software for all Modes 8.5 Flow Charts and Comments for All Software Modes8.5.1 The Mono Interrupt Driven Mode Using RD to Start Conversion Table 14. Instruction in the Program Header Step common file of all modes constants definition Program FilesOther Files Code verification Figure 6. Software Flow of the Mono Interrupt Driven Solution Common file of all modes constants definition 8.5.2 Mono Interrupt Driven Mode Using CSTART to Start ConversionCalibration procedure of the DAC Includes the complete software algorithm to control the monomode Pull Down CSTART Initialize SPISAVE Poll INTO Pin Until h/0 Transition Occurs This only works for one TLV1562 not multiple because CS is not used 8.5.2.1 Throughput Optimization† Maximum Performance at 1.2 MSPS with Internal Clock 8.5.3 Dual Interrupt Driven ModeFigure 8. Time Optimization monocst1 IMPORTANT NOTE The code has been optimized to maximize the data throughput. It was found that CSTART can be pulled low earlier than the data read instruction is performed by the DSP. This saves the 100-ns wait time in STEP 3 because the data read requires at least 100 ns. Therefore, CSTART gets pulled high directly after data read, and the interface becomes faster and gains throughput. This variation will be found in the code. The data acquisition is done in a small number of steps that explains everything inside the code Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 8.5.4 Mono Continuous Mode Figure 10. Flow Chart Mono Continuous Mode 8.5.5 Dual Continuous Mode Figure 11. Flow Chart Dual Continuous Mode Code verification 8.6.1.1 Constants.asm 8.6 Source Code8.6.1 Common Software for all Modes except C-Callable 42 SLAA040 set 000C0h Operate without calibrated inputs no offset 8.6.1.2 Interrupt Vectors 44 SLAA040 4C internal timer interrupt title ”COMMAND FILE FOR TLV1562.ASM” 8.6.1.3 linker,cmd8.6.1.4 Auto.bat File Linker.lnk COMMAND FILE counter for one channel Mainprogram Monomode.asmpointer address when using any of the following variables jump address to init. new channel sent value to register CR0 of the ADC 48 SLAA040 if SENDOUTSERIALendif if INT0DRIVENPOLLINGDRV endif elseif INT0DRIVEN if AUTOPWDNENABLEendif if DIFFINPUTMODE = bit*AR5,15-0 elseif NOINT0SIG 52 SLAA040 CALIBRAT.ASM 8.6.3 Calibration of the ADC 54 SLAA040 if SMECALIBRATION 56 SLAA040 Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 58 SLAA040 Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 60 SLAA040 if INT0DRIVENPOLLINGDRV 62 SLAA040 = bit*AR5,15-0 64 SLAA040 endif if SAVEINTOMEMORY Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP Mainprogram DUALIRQ1.asm 8.6.5 Dual Interrupt Driven ModeConstants definition - see 8.6.1.1 Constants.asm Interrupt Routine handler - see 8.6.1.2 Interrupt Vectors Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP Software Overview if SENDOUTSERIAL Software Overview Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 70 SLAA040 if POLLINGDRV 72 SLAA040 endif 74 SLAA040 8.6.6 Mono Continuous ModeMainprogram MONOCON1.asm Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 76 SLAA040 endif if EXTERNALCLOCK 78 SLAA040 Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 80 SLAA040 8.6.7 Dual Continuous ModeMainprogram DUALCON1.asm Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 82 SLAA040 endif 84 SLAA040 Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 80h samples of channel 1 will be stored beginning on 2000h 8.6.8 C-CallableMainprogram C1562.c TLV1562Channel, Save Memory Start address, NUMBEROFSAMPLES Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP 88 SLAA040 AR7+ = data@ADSAMPLE 90 SLAA040 Vectors.asm int2 returnenable 48 external interrupt int2 nop 92 SLAA040 Auto.batLinker.cmd 10 References 9 Summary