Software Polling, Advantage | Texas Instruments TLV1562 manual

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Texas Instruments TLV1562 manual Software Polling, Advantage, Disadvantage, Timed Solution

Contents

Application Report JulySLAA040 TParalInteMS3rflelADConvertertotheacing20C54xDSPtheTLV1562 IMPORTANT NOTICE Contents 8.5.5 List of Figures List of TablesFigures viSLAA040 2 The Board Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP1 Introduction 2.1 TMS320C54x Starter Kit 2.3.1 Suggestions for the ’C54x to TLV1562 Interface 2.2 TLV1562EVM2.3 ADC TLV1562 Overview 2.3.1.1 The Universal Interface Using RD or the CSTART Signal to Start Conversion 2.3.2 Recyclic ArchitectureFigure 2. TLV1562 to ’C54x DSP Interface of the EVM 2.3.3 Note on the Interface, Using an External ADC Clock Drive 2.4 Onboard Components2.4.1 TLC5618A - Serial DAC 2.4.2 THS5651 - Parallel Output CommsDAC Figure 3. TLC5618A to ’C542 DSP InterfaceFigure 4. THS5651 to C542 DSP Interface 3 Operational Overview 3.1 Reference Voltage Inputs3.2 Input Data Bits Table 1. Signal Connections 3.3 Connections Between the DSP and the EVM Table 3. 2-Position Jumpers 3.3.1 Jumpers Used on the TLV1562EVMTable 2. 3-Position Jumpers 8SLAA040 4 The Serial DAC/DSP System Table 4. DSP/DAC Interconnection Table 5. DSP Serial Port Signals and Registers 5 The DSP Serial Port 6 Other DSP/TLV1562 Signals 6.1 DSP Internal Serial Port Operation 7.1 Writing to the ADC 7.2 Mono Interrupt Driven Mode Using RD7 Conversation Between the TLV1562 and the DSP Table 6. DSP Algorithm for Writing to the ADC Table 7. DSP Algorithm for Mono Interrupt Driven Mode Using RD tDCSL-sample+1ADCSYSCLKtENDATAOUT = 41 ns 7.3 Mono Interrupt Driven Mode Using CSTART Table 8. DSP Algorithm for Mono Interrupt Driven Mode Using CSTART14 SLAA040 7.4 Dual Interrupt Driven Mode Table 9. DSP Algorithm for Dual Interrupt Driven Mode 7.5 Mono Continuous Mode Table 10. DSP Algorithm for Mono Continuous Mode16 SLAA040 7.6 Dual Continuous Mode Table 11. DSP Algorithm for Dual Continuous Mode 8 Software Overview 8.1 Software Development tools8.2 DSP Memory Map Figure 5. Memory Map 8.3.1 Optimizing CPU Resources for Maximum Data Rates 8.3.3 Timer Output8.3 Programming Strategies for the ’C54x, Explanations 8.3.2 Address and Data Bus for I/O Tasks 8.3.5 Generating the Chip Select Signal and the CSTART Signal 8.3.4 Data Page Pointer8.3.6 Interfacing the Serial DAC 5618A to the DSP GOTO MARK 8.3.7 Interrupt Latency8.3.8 Branch Optimization goto/dgoto, call/dcall MARK DP = #1 ARP = #5 8.3.9 Enabling Software Modules .if/.elseif/.endif 8.4 Software Code Explanation8.4.1 Software Principals of the Interface Advantage 8.4.1.2 Timed Solution8.4.1.1 Software Polling Disadvantage Advantages 8.4.1.3 Interrupt Driven Solution8.4.1.5 Setting the Right Switches Disadvantages Table 12. Switch Settings TaskTable 13. Instruction in the Program Header Step Table 14. Instruction in the Program Header Step 8.5 Flow Charts and Comments for All Software Modes8.5.1 The Mono Interrupt Driven Mode Using RD to Start Conversion 8.4.1.6 Common Software for all Modes Code verification Program FilesOther Files common file of all modes constants definition Figure 6. Software Flow of the Mono Interrupt Driven Solution Includes the complete software algorithm to control the monomode 8.5.2 Mono Interrupt Driven Mode Using CSTART to Start ConversionCalibration procedure of the DAC Common file of all modes constants definition Poll INTO Pin Until h/0 Transition Occurs Initialize SPISAVE Pull Down CSTART 8.5.2.1 Throughput Optimization† This only works for one TLV1562 not multiple because CS is not used 8.5.3 Dual Interrupt Driven Mode Figure 8. Time Optimization monocst1Maximum Performance at 1.2 MSPS with Internal Clock 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 Software Overview 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 Program Files 8.6 Source Code 8.6.1 Common Software for all Modes except C-Callable8.6.1.1 Constants.asm set 000C0h Operate without calibrated inputs no offset 42 SLAA040 8.6.1.2 Interrupt Vectors 4C internal timer interrupt 44 SLAA040 File Linker.lnk COMMAND FILE 8.6.1.3 linker,cmd8.6.1.4 Auto.bat title ”COMMAND FILE FOR TLV1562.ASM” jump address to init. new channel Mainprogram Monomode.asmpointer address when using any of the following variables counter for one channel sent value to register CR0 of the ADC if SENDOUTSERIAL endif if INT0DRIVENPOLLINGDRV48 SLAA040 endif = bit*AR5,15-0 if AUTOPWDNENABLEendif if DIFFINPUTMODE elseif INT0DRIVEN elseif NOINT0SIG 52 SLAA040 8.6.3 Calibration of the ADC CALIBRAT.ASM 54 SLAA040 if SMECALIBRATION 56 SLAA040 endif 58 SLAA040 Software Overview 60 SLAA040 if INT0DRIVENPOLLINGDRV 62 SLAA040 = bit*AR5,15-0 endif if SAVEINTOMEMORY 64 SLAA040 Software Overview Interrupt Routine handler - see 8.6.1.2 Interrupt Vectors 8.6.5 Dual Interrupt Driven ModeConstants definition - see 8.6.1.1 Constants.asm Mainprogram DUALIRQ1.asm Software Overview Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP Software Overview if SENDOUTSERIAL Software Overview 70 SLAA040 endif 72 SLAA040 if SAVEINTOMEMORY 8.6.6 Mono Continuous Mode Mainprogram MONOCON1.asm74 SLAA040 Software Overview 76 SLAA040 endif if EXTERNALCLOCK 78 SLAA040 endif 8.6.7 Dual Continuous Mode Mainprogram DUALCON1.asm80 SLAA040 Software Overview 82 SLAA040 endif if DIFFINPUTMODE 84 SLAA040 Software Overview TLV1562Channel, Save Memory Start address, NUMBEROFSAMPLES 8.6.8 C-CallableMainprogram C1562.c 80h samples of channel 1 will be stored beginning on 2000h Software Overview 88 SLAA040 AR7+ = data@ADSAMPLE Vectors.asm 90 SLAA040 int2 returnenable 48 external interrupt int2 nop Auto.bat Linker.cmd92 SLAA040 9 Summary 10 References