NCR 7454, User Manual, Page: 203 / 244

Chapter 6: NCR 7454 4x20 Customer Display 6-9
Set Diagnostic State
Format: 1B 04
Description: This state is exclusive from the On and Low Power states. This
command causes the firmware to display the current NCR part number
and firmware version of the device. For example, the current part
number and firmware version of the device are 008-0221537 and
V1.00.01) for two seconds and then step through each installed 256-
character set (default and user defined) displaying one character at a
time on all 40 display positions at a rate of about one character per
second. Start with the currently selected character set and then display
all of the characters from the other sets the same way. This continues
until one of the other state commands is performed. Prior display data
is saved and can be restored be sending the Turn On (state 3) com-
mand.
Set Display State On
Format: 1B 05
Description: This state is used for normal run-time conditions. This operation
instructs the firmware to leave one of the other states and begin
performing normal refresh operations. There may be a slight delay
before the VFD reaches the specified brightness setting when exiting
the Low Power State. This delay should not exceed 1 second from the
time the command is received until the time the VFD reaches the
specified brightness.
Highest priority is given to refresh operations and a lower priority is
given to host communications. Host communications still work, but if a
large amount of data is to be programmed in a very short time frame, it
would work faster if the Blank State was programmed prior to the
information transfer.
The Screen Save feature may be in force during the Display On state.
This means that after about five minutes of no new display activity, the
Screen Save feature could take over and cause the display to go blank
or begin walking from right to left.