Precision Measurement Engineering, Inc.
Precision Measurement Engineering, Inc.
SCAMP’s CPU circuit has a Light Emitting Diode (L.E.D.) installed on it. This L.E.D. can be seen by opening SCAMP and removing the longer electronics cover. The L.E.D. is located to the right of the Reset Button. See the picture below.
SCAMP flashes the L.E.D. at various times to indicate internal circuit conditions. Some flashes indicate normal operation, some do not.
NORMAL OPERATION
Reset Response
Immediately after the reset button is pressed, or after the last AA battery is installed into the digital battery pack, and if the USB is not connected, SCAMP will flash the L.E.D. twice. The L.E.D. will then remain off. This indicates normal reset response.
USB Response
Approximately 3 seconds after SCAMP is connected to the host computer via USB, SCAMP will light the L.E.D. continuously for the duration of the USB connection.
RS232 Response
SCAMP illuminates the L.E.D. immediately upon RS232 connection for the duration of the connection.
Data Acquisition Response
SCAMP illuminates the L.E.D. briefly whenever the supervisor is
active. Supervisor activity occurs about once per second and may be too brief to see.
However, when a 512 byte block of data is acquired, it is written to the MMC by the
Supervisor. This event takes longer and can be seen periodically as a brief flash of the
L.E.D. Upon conclusion of a profile the supervisor performs clean-up chores which takes
somewhat longer. The end of a profile can be seen as a longer L.E.D. flash, followed by no
further flashing.
ABNORMAL OPERATION
If SCAMP’s software determines that there has been an internal error it flashes the L.E.D. a certain number of times in a repeating pattern. If any of the following are observed, then remove all SCAMP’s batteries and contact PME.
| Repeating Flash Pattern | Cause | Notes |
| 2 | Unable to initialize MMC | Can sometimes be corrected by removing/reinstalling AA batteries |
| 3 | Unable to read MMC | |
| 4 | Unable to initialize profiler control block | |
| 5 | NMI interrupt | Low voltage at AA batteries. Replace |
| 6 | Stack overflow | |
| 7 | Undefined op code | |
| 8 | Protection fault | |
| 9 | Illegal word operand | |
| 10 | Illegal instruction address | |
| 11 | Illegal external buss access |