User guide

UG_6613_ 040 6613_PSU_1+1S_URT_V1_00 Firmware Description Document
Rev. 1.0 7
3 Serial Communication
The serial communication with the 78M6613 takes place over a UART (UART0) interface. The default
settings for the UART of the 78M6613, as implemented in this firmware, are given below:
Baud Rate: 38400bps
Data Bits: 8
Parity: None
Stop Bits: 1
Flow Control: Xon/Xoff
The firmware allows two types of communication protocols (modes) through UART0: CLI (Command Line
Interface) mode and auto-report mode (default operation).
4 Auto-reporting Mode
Upon application of 3.3VDC power, the 78M6613 will operate in Auto-reporting mode.
Data Packet : Auto-reported AC measurement data packet consisting of Voltage, Current, Watt, Power
Factor and Line Frequency send every accumulation cycle. Measurement data packet is send over
UART in ASCII format followed by line feed and carriage return.
Vrms Irms Watts PF Freq LF + CR
Measurement Parameter: The following table lists the measurement parameters and their respective bit
resolutions (LSB) that is sent over UART in ASCII format.
Measurement Parameter Resolution (LSB)
Voltage (Vrms) mV
Current (Irms) mA
Active Power(Watts) mW
Power Factor(PF) Range between 0 and 1000.
1000 indicative of 1.0 PF
Line Frequency(Freq) 0.01 Hz
5 Auto-reporting “Toggle” Command
To change from Auto-reporting mode to CLI mode (see Section 6 for details of the CLI mode), Ctrl Z
command must be sent from the host to the 78M6613 over the UART interface. A subsequent Ctrl Z
command will cause the 78M6613 to toggle back to Auto-Reporting mode.