| Chapter 6: NCR 7454 4x20 Customer Display |
| 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 |
| 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 |
| 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. |