Chapter 3: Installation |
Diagnostics
The 5972 Customer Display has internal Power Up Diagnostics that occur soon after power‐up or if a Reset Display command is received from the host software.
When the hardware is powered down, all registers and memory are lost. No recovery is possible.
The Power Up Diagnostics include the following tests:
•Micro‐controller test
•External character PROM test (VFD only)
•Pixel Number Display
Micro-controller Test
For serial communications, the CTS line is set in a Marking condition (negative voltage) at the start of the test. For VFD parallel communications, the Busy line is set active at the start of the test. The first test is the Micro‐controller test which checks operation at the Micro‐controller.
If an error is discovered, testing halts, and the firmware begins executing a forever do nothing loop. No response is sent to the host. If the Micro‐controller Test passes, the CTS and Busy line exception conditions are lifted.
External Memory Test Character (VFD Only)
A separate test is performed on the external character PROM, if it exists. The PROM status is noted and saved for terminal retrieval later using the Reset command.
If an error is discovered, all character sets stored in the PROM are considered invalid, and any command received attempting to switch to one of these character sets is treated as an invalid command and ignored.
