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Increasing Power Meter Transfer Rates Using a FT2232H Interface Chip. Ernest Yim, William Li, Samuel Gunaseelan. Introduction. “Make it faster” Possibilities Optimize code Change microcontroller PIC32 * ATSAM3U4E Cypress EZ-USB FX2 Use Ethernet Hi-Speed vs. Full Speed. Power Meter.
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Increasing Power Meter Transfer Rates Using a FT2232H Interface Chip Ernest Yim, William Li, Samuel Gunaseelan
Introduction • “Make it faster” • Possibilities • Optimize code • Change microcontroller • PIC32 * • ATSAM3U4E • Cypress EZ-USB FX2 • Use Ethernet • Hi-Speed vs. Full Speed
Power Meter • Reads power data • Calibration needed • Has two PIC24 microcontrollers • Guides written (fusdisk\powermeter) • Two channels • Full speed Fig. 1 – Power Meter
The Interface Chip • FTDI’s FT2232H • Cost effective • Mini-module (dev board): $27.00 • FT2232H: $6.70 • Hi-speed support • 12MHz clock (480Mhz w/ PLL) • 2 Channels Fig. 2 – FT2232H
Console Application Fig. 3 – Console application written to receive data on computer side
The Setup: Asynchronous Bit-Bang Mode Fig. 6-8 – power meter’s ADC (forward) output connected to ft2232h mini module for asynchronous bit-bang mode (connected to computer via USB)
Asynchronous Bit-Bang Mode • 6-8Mbaud rate • 4.8Mbaud (experimental max.) • Sample rate: ~83.33ns • 150% increase in speed • Tested by sending square waves into pins • Raw power data can be converted
The Setup: Fast Opto-Isolated Serial Mode Fig. 9-11 – power meter’s ADC (forward) output connected to ft2232h mini module for fast opto-isolated serial interface mode (connected to computer via USB)
Fast Opto-Isolated Serial Interface Mode • Serial • Transfer speed depends on external clock • No limit? • Translation of bits needed • Bit-shift register (PISO) • Little success with translation
Conversion: No pattern Fig. 12 – Screenshot of serial data (binary), no apparent pattern can be found to translate data, but ADC values seem to be in data
Verdict • Asynchronous Bit-Bang Mode • Works • Power data matches data of current powermeter • 150% increase • Fast Opto-Isolated Serial Interface Mode • Proper conversion needed • Possible potential for greater speeds Side Projects • Test notch, band-pass, band-reject filter designs • Test and calibrate power meters • Matching circuit
Acknowledgements I would like to thank everyone in the C7 Lab And especially, • Dr. Kullervo Hynynen • Vivian Sin • William Li • Samuel Gunaseelan