Advantech PCM-3780 manual Period Measurement, Using Advantech 32-bit DLL Driver, Using Direct I/O

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3.5 Period Measurement

3.5.1Using Advantech 32-bit DLL Driver

This approach is for a low frequency signal.

We recommend you to perform period measurement through our 32-bit DLL driver because it is the simplest way for both programming and wiring. Just connect the unknown single to Gate and the duty cycle will be measured by the software.

3.5.2 Using Direct I/O

This approach is for a low frequency signal.

Figure 3.4: Period Measurement

Implementing this measurement needs two counters, one for the up cycle period and another for the down cycle period. These added together gives the total period. The duty cycle can also be calculated by dividing the up period with the total period. Connect the unknown signal to each counter's gate.

Apply a standard clock pulse to each counter. Counter 0 counts the up cycle, while Counter 1 counts the down cycle. In PCM-3780, wiring is simple. Just connect the unknown signal to Counter 0, and use the regis- ter to select the gate source. Counter 0 selects "Gate N". Counter 1 selects "Gate N-1".

Apply the standard clock to both counters with the clock source selection register. It can change the clock for different measurement ranges. Counter 0 set as "Mode O" will make gate polarity positive. Counter 1 set as "Mode O" will make gate polarity negative.

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Contents PCM-3780 Ch Counter/Timer with Ch TTL DIO ModuleCopyright Acknowledgements Two Years Product Warranty CE Notification FCC Class a Technical Support and Assistance Packing List Page Contents Appendix Specifications Introduction Features Counter Modes PCM-3780 Counter ModePCM-3780 Counter Mode Applications Installation GuideInstallation Flow Chart Register-level Programming Software OverviewDevice Drivers on the companion CD-ROM Device DriversProgramming Tools Device Drivers Programming RoadmapProgramming with Device Drivers Function Library Troubleshooting Device Drivers ErrorWiring Cables AccessoriesWiring Boards Hardware Installation Unpacking Companion CD-ROM Driver InstallationDifferent Options for Driver Setup Installing the Module Hardware InstallationPage Pin Assignments & Jumper Settings Overview Signal ConnectionsInterrupt Level IRQ Setting JP1 Switch and Jumper Settings Base Address Setting Base Address Setting SW1CN3 I/O Port Connector Connectors Pin AssignmentCN4 Counter Interface Connector Reference Direction Description Connector Signal DescriptionUsing Direct I/O Using Advantech 32-bit DLL DriverPeriod Measurement Frequency Measurement Frequency MeasurementSpecifications Digital Input/Output Programmable CounterGeneral Page Block Diagram Appendix B Block Diagram Register Structure & Format I/O Port Address Map Appendix C Register Structure & FormatTable C.1 Register Offset Address Table Register FormatCE CE CM6 to CM3 Count Control CM6 Counter 0/1 Mode RegisterCM2 Output Enable Control CM1 to CM0 Output ControlCM15 Gate Active Edge or Level CM7 Count Source EdgeCM13 to CM12 Gate Source Selection CM14 Gating Polarity SelectionCounter 0/1 Hold Register Counter 0/1 Load RegisterCE1 to CE0 Counter Command Enable Bit Counter 0/1 Command RegisterCounter Command Enable Register C2 to C0 Command CodeInterrupt Status Register Interrupt Control RegisterO Direction Control Bit Interrupt Clear RegisterDirection Control Register Port A/B/C Interrupt Status RegisterDV3 to DV0 Fout Divider Divide by 1 to 16 0000 = Divide by Fout RegisterFS2 to FS0 Fout Source FOE Fout Output EnableWaveform of Each Mode Counter Mode Descriptions Appendix D Waveform of Each ModeTable D.1 PCM-3780 Counter Mode Table D.2 PCM-3780 Counter Mode Software-Triggered Strobe with No Hardware Gating Mode a WaveformsSoftware-Triggered Strobe with Level Gating Mode B WaveformsHardware-Triggered Strobe Mode C WaveformsRate Generator with No Hardware Gating Mode D WaveformsRate Generator with Level Gating Mode E WaveformsNon-Retriggerable One-Shot Mode F WaveformsSoftware-Triggered Delayed Pulse One-Shot Mode G WaveformsMode H Waveforms Hardware-Triggered Delayed Pulse Strobe Mode I WaveformsVariable Duty Cycle Rate Generator with No Hardware Gating Mode J WaveformsVariable Duty Cycle Rate Generator with Level Gating Mode K WaveformsHardware-Triggered Delayed Pulse One-Shot Mode L WaveformsHardware-Triggered Strobe with Edge Disarm Mode O WaveformsNon-Retriggerbale One-Shot with Edge Disarm Mode R WaveformsHardware-Triggered Delayed Pulse Strobe with Edge Disarm Mode U WaveformsHardware-Triggered Delayed Pulse One-Shot with Edge Disarm Mode X Waveforms