S3 Help 2.5
To install this new HELP software into S3, a new Library ROM needs to be created. This procedure is described below:
- Download S3HELP25.HEX to S3 in the normal way. S3HELP25.HEX is an Intel Hex file. The data will reside between addresses E000-FFFFH.
- Do a RAM checksum (CKSUM key) from E000 to FFFF:
- CHECKSUM E000,FFFF or >CH E000,FFFF
- The resulting SUM should be: 0D0D1A
- BURN a (blank) 2764 or 27C64 from E000-FFFFH:
- >BURN 2764-INT
- 12.5V TO PIN 1
- SECTOR 07=E000,FFFF
- Do a ROM checksum (F3). The SUM should be the same as the RAM checksum above.
- With the freshly BURNt HELP ROM in S3's ZIF socket, press HELP, and then ENTER. The HELP program will now load, and S3 should the display the following sign-on message:
- DATAMAN S3 HELP 2.5
"But my S3 has lost it's HELP - I can't BURN a 2764"
There is another method of installing a HELP ROM into S3, which does not involve BURNing an EPROM and makes use of an undocumented S3 command. This procedure is described below:
- Download S3HELP25.HEX into S3, and perform a checksum of RAM, as described in sections 1 & 2 respectively.
- Press ESC, and an asterisk should appear. Now press HELP. S3 should display the following:
- *UH XXXX,XXXX
This command is called User to Help. It transfers data from USER RAM into the HELP RAM. There are three blocks of code which need to be transferred to the USER RAM. The HELP code can't be transferred in one go, as reserved areas of HELP RAM would be corrupted, and S3 would crash. The addresses of these blocks are as follows:
- E000-FD4F
- FE50-FEFF
- FF02-FFFF
Enter the first set of addresses, and press ENTER. Now press ESC-HELP and enter the second set. Do the same with the third set. S3's screen should look as follows:
- UH E000,FD4F
- UH FE50,FEFF
- UH FF02,FFFF
You will notice that the prompt symbol ">" doesn't appear after entering the third set of addresses.Switch S3 OFF and then back ON. The HELP program will now load, and S3 should the display the following sign-on message:
- DATAMAN S3 HELP 2.5
If this message doesn't appear, or S3 crashes, the S3HELP25.HEX file probably wasn't downloaded correctly, or the incorrect addresses were entered in the UH command. If you experience any difficulties installing your HELP ROM, please submit our technical support form.