The Sinclair QL Forum

The Philips branded '8049' controller chip in my QL is a MAB 8049H P A038.

Does anyone know if a MAB 8049H P A028 would also work? I'm not sure if the A038 is any different or if that slight difference is irrelevant.

Thanks.

Yes I believe the MAB 8049H P A028 will work. The A028 may just be a revision or date code

Cheers

Bill

That's enough reassurance for me! I'll get one and try it out. Thanks.

Any non-SInclair branded 8049 will very probably not work in the QL.

The 8049 is a mask-programmed MCU that does not only come as hardware according to specifications in the data sheet, it also contains a (non-changeable) ROM that contains the firmware. That firmware is specifically made for the QL Keyboard and sound processing. Something you can get off eBay will probably contain the firmware for a dishwasher - not very useful.

Tobias

None of them are Sinclair branded, but it looks like you were right tofro! I put the A028 chip in and it made an angry beep and hung at the multicoloured reset screen.

A known working A038 fitted and all is well again. I don't know 100% if the A028 was fully ok, but it's not worth trying it again, I'll just get the correct A038 instead.

Hi,

I have thought, Intel's 8048, 8049 are single chip microcontrollers, having program and data memory.
And can be user programmed simillarly as more modern PIC micros. I believed program resides in internal EPROM. As that what HERMES is all about, is just a new firmware for IPC (8049)?

Apologies, getting confused here.

Tomas

With Micros's like this they offered them in various formats:

EPROM piggy back - these have a socket on the back of the chip itself for the program memory

EPROM Internal - device has an EPROM for Program memory on board the chip and has a clear window to allow UV erase

EPROM OTP - this is the same as the above, but with no window - it's a one time programmable.

MASK Programmed ROM - these devices are programmed at the factory, the code can't be changed afterwards. These are usually the cheapest, as you would run off a large batch of them.


Unlike PIC devices and the ATMEL chips which are flash programmed, these older Micro's are built for one design and then that's set in stone - meant for the consume / appliance market where firmware changes aren't really expected.

The first Hermes was just another version of this chip running a differnet program, the SuperHermes was a totally different micro (PIC Microcontroller) on a piggy back board.

More info here :

https://en.wikipedia.org/wiki/Intel_MCS-48

Hi,

Very interesting read, but it does not say that Laurnce Reeves produced a debugged more efficient version of the 8049 called Hermes.

Personally, I would use Hermes over the 8049, it works better in the QL and is still available on Sellyouretro.

Derek_Stewart wrote:Hi,

Very interesting read, but it does not say that Laurnce Reeves produced a debugged more efficient version of the 8049 called Hermes.

Personally, I would use Hermes over the 8049, it works better in the QL and is still available on Sellyouretro.

No - but I only meant to explain that Hermes is using another 8049 chip, rather than the original and its program code is different - sorry if I didn't explain myself. Having used both Hermes and SuperHermes Lite in the past, both were excellent products and brought much needed improvements without breaking anything else.