6 chip st TOS upgrade

[soviet9922]

Hello i have a old STf and its´a 6 chip rom model have tos 1.0 like to upgrade it to 1.4.
Its possible to change the roms to eproms ? what eprom i should use ?.
I have seen guides but are for 2 roms STs.


This is the board.

Thanks

[joska]

Atleast my own STM can be jumpered between 6 and 2 chip mode. I would assume that the same can be done with the STF.

You'd need 128Kb EPROMS, 27C010.

http://www.atari-forum.com/viewtopic.php?t=16638

[czietz]

As far as I know, not all STs can be changed to 2 ROMs. In that case six 32Kx8 EPROMs (27C256) should work.

[joska]

All ST's can be changed to 2 ROM's, but the amount of work involved may differ

[exxos]

Its not easy, but this is my solution. viewtopic.php?f=15&t=30868

[soviet9922]

As far as I know, not all STs can be changed to 2 ROMs. In that case six 32Kx8 EPROMs (27C256) should work.

So i can just burn 6 27c256 and drop them in, don't need to do any kind of mods to the board ?

[soviet9922]

Its not easy, but this is my solution. http://www.atari-forum.com/viewtopic.php?f=15&t=30868

It look very nice, but this ST its in very bad shape i don't want nothing to fancy just replace the TOS ROMs for EPROMs.

[joska]

So i can just burn 6 27c256 and drop them in, don't need to do any kind of mods to the board ?

Yes, atleast that's true in my STM. I would be surprised if the STF used different ROMs.

[czietz]

As far as I know, not all STs can be changed to 2 ROMs. In that case six 32Kx8 EPROMs (27C256) should work.

So i can just burn 6 27c256 and drop them in, don't need to do any kind of mods to the board ?

Yes, the pinout of Atari's 256kbit (32kByte x ROMs matches the pinout of 27C256 EPROMs. The only thing you have to figure out is which EPROMs goes where.

[soviet9922]

As far as I know, not all STs can be changed to 2 ROMs. In that case six 32Kx8 EPROMs (27C256) should work.

So i can just burn 6 27c256 and drop them in, don't need to do any kind of mods to the board ?

Yes, the pinout of Atari's 256kbit (32kByte x ROMs matches the pinout of 27C256 EPROMs. The only thing you have to figure out is which EPROMs goes where.

Great i think i can manage that!.
Going to try EMUTOS just for the sake of it, the best tool to split it is PP's rom splitter for the st i suppose?.

[soviet9922]

Theres any place that show here HI-0 HI-1 HI-2 LO-0 LO-1 LO-2 should go ?

[DarkLord]

See if any of these pics help...

TOS 1.4 chipset-b.jpg

atarimegast2rev5_B.jpg

[frank.lukas]

Theres any place that show here HI-0 HI-1 HI-2 LO-0 LO-1 LO-2 should go ?

520 /1040ST old 520, 1040 (new) und Mega ST

U2-------------------U48 - U3 (HI-2) Adreßlage $FE0000 bis $FEFFFF
U3-------------------U59 - U6 (HI-1) Adreßlage $FD0000 bis $FDFFFF
U4-------------------U63 - U9 (HI-0) Adreßlage $FC0000 bis $FCFFFF
U5-------------------U53 - U4 (LO-2) Adreßlage $FE0000 bis $FEFFFF
U6-------------------U62 - U7 (LO-1) Adreßlage $FD0000 bis $FDFFFF
U7-------------------U67 - U10(LO-0) Adreßlage $FC0000 bis $FCFFFF

[soviet9922]

Thanks for the information, split the 192k 1.04 rom using PP´s split tool burned it and work great .
Tried to do the same using EmuTOS 192k rom but only got a black screen, i´m not sure why i cannot get EmuTOS to work .

[czietz]

Which version of EmuTOS exactly? Fairly recent ones are in fact known to successfully boot on an STf.

[frank.lukas]

Use the Romsplit.ttp to split EmuTOS ...