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 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