The Sinclair QL Forum

Hi, I had a look at the QEP III manual, which is a little lacking in a lot of places, but the Options Sub Menu indicate a Jumble option to jumble the data or address line. The manual should of really describe the jumble function. The jumble function allows any data line to be swapped for any other ...

The I2C "hardware" is a GAL chip that's used in conjucton with some I2C primitive code to give basic I2C funtionality - a driver on a seperate disk provides the rest of the code required to use I2C from Basic / Assembler. There is a new vector for I2C provided by Minerva. The Minvera I2C ...

The I2C "hardware" is a GAL chip that's used in conjucton with some I2C primitive code to give basic I2C funtionality - a driver on a seperate disk provides the rest of the code required to use I2C from Basic / Assembler. There is a new vector for I2C provided by Minerva.

I posted pictures earlier in this thread of the IC that needs to be replaced in the video circuit - along with the link to the icl information that explains which chip is swapped for which other chip (74LS240 to 74LS244) from memory.

I think they are all getting rare - there was a guy repairing boards but he never has cases for these things - I just want a case!

Didn't the ozzie's have a version of this too?

Found this baby on RS components:

https://ly.rsdelivers.com/product/micro ... 44/1784856


No idea on pin compatibility - will have to check over the weekend

looks like document AN726 covers migration from pic17cxxx to pic18cxxx - but sadly can't find a copy of this on Microchip site anymore. The pic18 range are flash based with 100 year retention, and would not require too much code tweaking to port across from the 17C42 device. The problem is of course...

If the source was available, then perhaps a newer flash based pic could be used, with perhaps a simplified design offering the same or better functionality?

There are several families to chose from, and many of the PIC's support hardware UART's, timers, Flash for both program and data storage.

Interesting - for their OTP Eprom products - they are claiming 10 years retention: https://www.microchip.com/en-us/products/memory/otp-eprom So it's possible that the program has corrupted over time. I must admit I thought these babies were flash, but then you'd still need the program code to reflas...

I'll pull it out of the drawer tomorrow and identify the part that does the job of the 8049. That part. It was programmable, and lost its program. I believe it's a 17 series Microchip PIC - 17c42 or something like that - these are flash programmable parts - I am not sure on the retention period for...