MSA ProtoCessor FPC-ED2 - Protocessor Simple Protocol (PSP) Specification; Purpose of the Protocol; Protocol Description; Quick Start - Demonstrates the Simplicity of the Application

7 ProtoCessor Simple Protocol (PSP) Specification
7.1 Purpose of the Protocol
The ProtoCessor Simple Protocol (PSP) is recommended in instances where the ProtoCessor is the Server and the OEM
CPU is the Client.
• Implemented on the “Host” or “Application” CPU on the OEM circuit board (Microcontroller).
• Defined as an ASCII protocol in order to facilitate debugging, analysis and implementation.
• Allows data to be transferred to and from the ProtoCessor.
• Allows the Host Microcontroller to configure aspects of the ProtoCessor such as BACnet MS/TP MAC Address, Node-
ID, baud rate.
• Data that is written to the ProtoCessor is available to other devices on the ProtoCessor Ethernet connection. Data
written to the ProtoCessor by other devices over the Ethernet protocol is available to be read by the Host CPU.
7.2 Protocol Description
7.2.1 Quick Start – Demonstrates the Simplicity of the Application
Assuming a ProtoCessor is installed with a Factory Default configuration where there are no configuration commands
necessary; there is no need to configure any aspects of the ProtoCessor unless the application justifies the additional
complexity.
• The first data point from the ProtoCessor is the “Read Data”. The transaction between the Application Microcontroller
and the ProtoCessor would appear as follows:
From Host CPU/MCU:RD-NA:data,OF:0<cr>
Response from ProtoCessor:27.3<cr>
• The 27th value in the ProtoCessor is the “Write Data”. The transaction would appear as follows:
From Host CPU/MCU:WD-NA:data,OF:26,VA:23.9<cr>
Response from ProtoCessor:OK<cr>
• The FMT command in the poll from the Host CPU to the ProtoCessor can be used to specify the format of the data
traveling to and from the ProtoCessor. If no FMT is specified, then the ProtoCessor returns a floating point value.
From Host CPU/MCU:RD-NA:data,OF:0,FMT:H<cr>
Response from ProtoCessor:0x89CA<cr>
7.2.2 Serial Parameters
The PSP has the following default serial parameter settings:
Baud 38400
Data Bits 8
Parity N
Stop Bits 1
Minimum Poll Delay 10ms
Recommended Poll Delay 100ms
19 ProtoCessor Design Guide