User manual

MCP250XX User’s Guide
DS51266C-page 22  2004 Microchip Technology Inc.
2.5 EXPLAINING THE CAN MESSAGES
At this point, the two nodes (PC Node and Node B) should be communicating normally
and a message should be showing up in the Output window (Figure 2-5) at regular
intervals. Pushing GP4, GP5 or GP6 causes other messages to show up in the Output
window, with the status being reflected graphically in the Demo window. Turning the
potentiometers will cause the data fields to change.
This section explains the CAN messages as seen in the Output (Bus Monitor) window.
TABLE 2-1: CAN MESSAGES EXPLAINED
Identifier Length Data Explanation
0x008 3 “Write Register” Input Message
(IM)
DB0 (address) is either 0x23 or 0x26
(PR1 or PWM2DCH).
0x018 8 Read A/D Regs “Read A/D Regs“ IRM followed by
OM.
0x280 0 None On-bus message.
0x290 8 Read A/D Regs A/D Threshold Detection (R20, POT
and PWM2 duty cycle).
0x7FF 0 None Command Acknowledge in response
to IM.