MCP3909-I/SS Microchip Technology, MCP3909-I/SS Datasheet - Page 27

• Manufacturer Part Number: MCP3909-I/SS
• Description: IC POWER METERING-1 PHASE 24SSOP
• Manufacturer: Microchip Technology

Specifications of MCP3909-I/SS

• Package / Case: 24-SSOP (0.200", 5.30mm Width)
• Input Impedance: 390 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.85V
• Current - Supply: 2.3mA
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Meter Type: Single Phase
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Supply Voltage Range: 4.5V To 5.5V
• Digital Ic Case Style: SSOP
• No. Of Pins: 24
• Interface Type: Serial, SPI
• Supply Voltage Max: 5.5V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MCP3909EV-MCU16 - EVALUATION BOARD FOR MCP3909MCP3909RD-3PH1 - REF DESIGN MCP3909 3PH ENGY MTR
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

3.1
3.2
© 2009 Microchip Technology Inc.
OVERVIEW
MAIN LOOP
This section discusses the dsPIC firmware structure, peripheral resources, important
program flows, and explanations of project files included in the firmware zip files
included with the system. See Appendix D. “50/60 Hz Meter Operation” for
converting to 60 Hz code.
• Calculate all electrical parameters in frequency domain
• MCP3909 device communication
• Detect voltage/current phase order, and determine missing phases
• Generation imp/kWh power pulse
• UART communication
The main loop of the entire dsPIC33F program is shown in Figure 3-1.
FIGURE 3-1:
ENERGY METER REFERENCE DESIGN
Chapter 3. Firmware
Initialize on-chip
peripherals and variables
and MCP3909 device
acquisition complete?
Process UART
comm. commands
Sampled 3 cycles?
Main Loop Chart.
Main Program
Clear WDT
Neutral data
MCP3909 / DSPIC33F 3-PHASE
No
No
Yes
Yes
Calculation()
Compute elec.
parameters
Compute
neutral line
current
DS51723A-page 27