MCP3909RD-3PH3 Microchip Technology, MCP3909RD-3PH3 Datasheet - Page 52

• Manufacturer Part Number: MCP3909RD-3PH3
• Description: REF DESIGN FOR MCP3909 W/18F2520
• Manufacturer: Microchip Technology

Specifications of MCP3909RD-3PH3

• Main Purpose: Power Management, Energy/Power Meter
• Utilized Ic / Part: MCP3909, PIC18F2520, PIC18F4550
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design
6.2
6.3
DS51723A-page 52
TEST CONNECTION COMMAND
TOTAL DATA REQUEST
Variant-length frame structure is used and data communiate in bytes. The command
protocol structure is defined as following.
TABLE 6-2:
• The START word has 2 bytes, which are 0x00, 0xFF ( PC to target board) or 0xFF,
• Command word is 1 byte which indicates the type of the command
• Data length word is 1 byte that indicates the length of data field
• The data field word has multiple byte(s) that varies with command types
• Checksum word is a single byte, whose content equals to the XOR value of all
• Stop word is 1 byte with the content of 0xE0
This command is sent from the PC to the meter to setup and test the connection.
TABLE 6-3:
TABLE 6-4:
This is the main command retrieves all the calcuated data from the dsPIC33F. This
command gathers data from all 3 phases including total energy, power, and power
factor data.
TABLE 6-5:
TABLE 6-6:
0xFF, 0x00
0xFF, 0x00
0xFF, 0x00
0xFF, 0x00
0x00 (target board to PC)
bytes sent before it
2 Bytes
START
START
START
START
START
Command
Command
Command
Command
Command
1 Bytes
TYPICAL PROTOTOL
PC TO METER (7 BYTES)
METER RESPONSE (8 BYTES)
PC TO METER (7 BYTES)
METER RESPONSE (104 BYTES)
0x41
0x42
0x42
0x43
Length
Length
Length
Length
Length
1 Byte
Data
Data
0x00
Data
0x02
Data
0x00
Data
0x62
0xA5, 0X5A
Data Field
Data Field
Data Field
Data Field
Data Field
98 bytes
N Bytes
0x00
0x00
Check Sum
Check Sum
Check Sum
Check Sum
Check Sum
© 2009 Microchip Technology Inc.
1 Byte
XX
XX
XX
XX
1 Byte
STOP
STOP
STOP
STOP
STOP
0xE0
0xE0
0xE0
0xE0