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Display Texts

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General

The channel labels (names) that appear on the FM1000 numeric keypad display are ASCII texts strings with a maximum length of 10 characters. These strings can be customized by editing the contents of the 27C512 display EPROM. Radio amateurs will typically want to see frequencies on the display. However any frequency shown on the display is simply EPROM-resident text, and not data read from the EEPROM as some will like to believe. In other words you can assign any name you want to a channel, although the actual RX and TX frequencies will always be determined by what's been programmed into the 24C16 EEPROM, not the display EPROM!. To be able to customize the display texts you will need:

a hex file editor such as Hex Workshop which is capable of computing file checksums (16 bit);
an EPROM programmer and if necessary an eraser.

Quick method (advanced users)

Read out 27C512 display EPROM, copy higher half (8000-FFFF) into a new file starting at 0000.
Edit channel labels, see below. Max. 10 characters per label. Leave separator bytes 00 unchanged!
Clear checksum bytes at 7FFE and 7FFF to 00.
Have the hex editor calculate the 16-bit checksum of the entire file. Make a note of the checksum and enter it at 7FFE and 7FFF.
Program file into a 27C256.

Extensive method (courtesy Darren Salter)

The Keypad Console code is normally supplied in a 27C512 EPROM even though a 27C256 EPROM could be used. The code is normally blown into both halves to avoid failures caused by selecting the wrong half of the EPROM. So the code lies in the range 0000 to 7FFF, and is repeated from 8000 to FFFF.  The following text will refer to the lower EPROM half, with the upper half figures given afterwards in brackets.

The standard Alphanumeric Keypad Console will be linked by LK4 to use the upper half of the EPROM and so a copy of the code must be present here.

Moving blocks of code:

If you have code in RAM from 8000 to FFFF hex and wish to duplicate it in the lower half of the EPROM then proceed as follows.

Select the program option and the following parameters:

From Memory Address = 8000

To Address = 0

Block size = 8000

Checksum:

A checksum is stored at locations 7FFE and 7FFF (FFFE and FFFF). This checksum is calculated for the data in the range 0000 to 7FFD (8000 to FFFD) inclusive. Note that this is a range of 7FFE.

To calculate the checksum using a Unisite go to 'Device Checks' and then 'Sumcheck Display'. Select start address 0000 (8000) and data size 7FFE. The checksum that is required is displayed twice as 'Individual Sumcheck' and as 'Set Sumcheck'. Do not use the 'User RAM Sumcheck'. The checksum returned will be 4 bytes long, i.e. 8 hex digits. Take the two Least significant bytes and enter them at 7FFE and 7FFF (FFFE and FFFF). Enter the numbers in the order that they appear in the checksum. For example: If the Unisite checksum is 12345678 Hex, then we require the Least Significant half which is 5678 Hex. This is entered by setting 7FFE Hex to 56, and 7FFF to 78 Hex.

Memory Locations:

Channel Labels are stored in order from channel 00 to 99.

Channel Labels are found at 4E1E to 5269 hex (CE1E to D269).

The area occupied by Channel Labels is 4AA hex.

Test Mode messages are at 529C to 53FE hex.

Messages are at 5410 to 54C8 hex, and again at 551F to 554E hex.

Error Messages are at 61A2 to 61EA hex, and again at 6227 to 6242 hex.

Darren Salter, 18-02-93.

 

Below is an example of how it's done using UltraEdit32.

 

 

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Last modified: February 15, 2002