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2.1 MPU6 FAULT CODES
Alarm Messages
When an alarm occurs during normal operation an error message is shown on the integrated
LCD display of the MPU6.
The message generally comprises of three parts, which are displayed in succession.
The display shows the alarm number, e.g. ALARM 54
–
11
–
CPU BUS ERROR
The first two digits are the BACTA industry alarm code. The second two digits are the Barcrest
alarm code. The third part is a brief description of the fault encountered.
Class of alarm
The various alarms, which can occur on the MPU6 system, are grouped into TEN classes.
When a fault occurs, the first digit of the Barcrest alarm number shows the class of alarm
A complete list of alarm messages, related to the associated BACTA and Barcrest fault code
numbers are shown in the following sections.
Class 1 alarms
Known as processor exceptions, these are errors detected by the CPU. They can be caused by
hardware faults in components on the CPU bus, e.g. CPU, RAM, PROMs, and DUART etc.
When shown on the display these alarms range from 11 - 1E with a Bacta code 54
BACTA. Code
BARCREST No.
MESSAGE
54
11
CPU BUS ERROR
54
12
ADDRESS ERROR
54
13
ILLEGAL INSTRUCT
54
14
DIVIDE BY 0
54
15
BOUNDS CHECK
54
16
OVERFLOW TRAP
54
17
BAD INTERRUPT
54
18
UNUSED TRAP
54
19
BAD STACK FORMAT
54
1A
UNINIT IVECTOR
54
1B
PRIV VIOLATION
54
1C
TRACE EXCEPTION
54
1D
BREAKPOINT
54
1E
RESERVED VECTOR
54
1F
WATCH DOG RESET
