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5160 BIOS Upgrade questions

A

Abbub

Experienced Member
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Mar 14, 2011
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Fort Collins, CO
Okay, so I've got a 5160 with the 11/08/82 BIOS in it.

I've also got an IBM Model M keyboard, which sort of 'works' with the system. (The main section of the keyboard works, but the arrow keys and number pad (when numlock is turned off) do not.

I see under the list of changes for the 01/10/86 BIOS that it includes "Added support for the 101-key Enhanced keyboard."

Will this 'fix' the system so that the Model M works completely as expected?

It seems like it'd be a worthy effort to upgrade to this newer BIOS anyway, if for no other reason than to add support for 720k 3.5 inch disks...which leads me to the next question.

What's the best method for updating the BIOS on a 5160? I assume the BIOS binaries are out on the internets somewhere. I have an EEPROM burner.

U18 and U19 both need to be burned, I assume. Both are listed as '32k' chips in the 5160 BIOS FAQ. Are chips I can burn to replace my existing BIOS readily available, or are these like the various ROM chips on the C64 that are no longer available to buy new?

Also, I assume the BASIC ROM is a different chip than the BIOS chips?

Any information and/or guidance is appreciated!

Thanks!
 
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Okay, after some help from the IRC channel and a bit of digging around, it looks like a need two 27256-20 EPROMS and a source for the binaries. :D Unicorn Electronics appears to have the parts.
 
any chance you'd be willing to perhaps buy a few sets of eeproms from unicorn and re-sell BIOS upgrade kits? I'd take a couple sets of those for sure.
 
hargle, yeah, I have no problem getting some extras and letting people have them at 'cost of chip + shipping'. It looks like the chips are about 3 bucks a piece, so I imagine a 'BIOS upgrade kit' will come in around 7 bucks shipped.
 
The keyboard interface hardware in the 5150 and 5160 differs signifficantly from the keyboard interface in the AT in that it is by definition just a 'dumb' receiver. The keyboard is also generally very simple, as all it does is to send a code when a key is pressed and a countercode when a key cheases to be pressed. It is also in charge of repeatingly send codes for keys which are being held down for some amount of time. This is basically all it does; how the codes are interpereted and presented is controlled by the BIOS.

The issues you note with the keyboard keys not responding when the numlock is off may be related to how the microcontroller in the Model M keyboard itself relates to the issues with the XT interface (mostly on the software side). The BIOS in at least the early XTs will not be able to differentiate between the numerical keys and the numerical keys on the num-pad, so when the numpad is turned on, the arrow keys would not work as intended; in which case it's more appropriate to just disable them to avoid any confusion. If it is like this, then it will not work to upgrade the BIOS.

I don't know exactly what support the later BIOS improves when it comes to the Model M keyboards, but I think this mostly relates to some of the keys not prevously present on the 83-key keyboards (like F11 and F12). If you want to upgrade the BIOS, you will have to get some 32KB EPROMs programmed with the more recent BIOS. BASIC will be included within these EPROMs, as it is somewhat merged with the BIOS.
 
hargle said:
eeproms
Click to expand...

If it's EEPROMs, then make sure they have some software dataprotection scheeme. XT boards up till Revision 2 will route A14 to two separate pins to support both 8KB and 32KB EPROMs, but one of these pins are also used as the /WE line on 32KB EEPROMs; In other words, EEPROMs will get written to when certain parts of them are accessed.
 
per:

Yeah, I was aware that it wouldn't work with a standard AT keyboard, but my understanding is that a Model M isn't a 'standard AT keyboard' and that the later XTs actually shipped with Model M's that just didn't have status LEDs. On this system, with the '82 BIOS, a bog standard AT keyboard just plain doesn't work, but the Model M actually does (except for the status LEDs and the arrow keys as mentioned). I didn't think that I'd be able to get the status LEDs to work, but I figured that the arrow keys might with the new BIOS. In any event, since I have the EPROM burner and the chips are relatively cheap, and also since there appear to be advantages above and beyond the keyboard changes, I think I'll probably just go for it.
 
per said:
If it's EEPROMs, then make sure they have some software dataprotection scheeme. XT boards up till Revision 2 will route A14 to two separate pins to support both 8KB and 32KB EPROMs, but one of these pins are also used as the /WE line on 32KB EEPROMs; In other words, EEPROMs will get written to when certain parts of them are accessed.
Click to expand...

yeah, I was going to get the 27256-20 parts, which are EPROMS.
 
Some keyboards can detect if they are connected to an XT, and then they may switch over to "XT" mode. In this case the microcontroller in the keyboard is programmed to spesificly take care of what issues the key layout may cause to the XT interface, in addition to change the data transfer protocol to be XT-compatible.
 
My employer just sent 16,000 27c256 EPROMs to electronic recycling a few months back :( I picked a few, but only about a hundred. I'd be willing to load them up with images and send them to people on demand if needed until the supply runs out. PM me.

(Note: They are AMD AM27C256-200DC) [200 ns]
 
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