Switchless JiffyDOS for C64

[plazma]

I finished my modification. I try to learn blogging so you can read the full story HERE

 

[roy_bates]

very useful.

the schematic for this would be nice.

 

[protek]

Nice mod!

I know the most common practise is to include JiffyDos and the Original Kernal on the same chip but are there adapters that use two chips, like the Kickstart switchers? I got my JiffyDos written on 27128 and my C128 is currently permanently set as a JiffyDos Machine. I'd like an adapter that takes both the original and JiffyDos ROM, switchless of course.

 

[plazma]

Nice mod!

I know the most common practise is to include JiffyDos and the Original Kernal on the same chip but are there adapters that use two chips, like the Kickstart switchers? I got my JiffyDos written on 27128 and my C128 is currently permanently set as a JiffyDos Machine. I'd like an adapter that takes both the original and JiffyDos ROM, switchless of course.

It is possible and easy to make. But why have a bigger board with two ROM chips when you can do with only one?

 

[protek]

Nice mod!

I know the most common practise is to include JiffyDos and the Original Kernal on the same chip but are there adapters that use two chips, like the Kickstart switchers? I got my JiffyDos written on 27128 and my C128 is currently permanently set as a JiffyDos Machine. I'd like an adapter that takes both the original and JiffyDos ROM, switchless of course.

It is possible and easy to make. But why have a bigger board with two ROM chips when you can do with only one?

Well, I got the ROMs already on separate chips and I thought it would be fun.

 

[plazma]

Well, I got the ROMs already on separate chips and I thought it would be fun.

Pay me a visit and I'll burn a new single chip ROM for you

 

[protek]

Well, I got the ROMs already on separate chips and I thought it would be fun.

Pay me a visit and I'll burn a new single chip ROM for you

Thanks but I have an EPROM burner and I needed two chips anyway as it is C128. I'd love to see your collection of retro goodness though.

 

[Cryton]

Ohhhh loving this, nice work mate. Roy's right a schematic would be really useful

 

[plazma]

A quick schematic added.

 

[roy_bates]

great stuff,thank you.

 

[wilykat]

+rep for schematic

 

[MCes]

Hi,
pay attention at the dates...
I developed a hole-less rom exchanger (4 rom banks select) on power on:
http://postimg.org/image/bcp6t3bft/
the tread is in:
http://ready64.it/forum/index.php?a...512f0f53fca&search_in=posts&result_type=posts
I explain the necessity of using an 74 HCmos.
My post end with: "chiunque è libero di sperimentare questo circuitino (ci mancherebbe...) ma se lo si vuole diffondere richiedo la citazione della fonte e se qualcuno volesse adoperarci uno sfruttamento economico mi contatti PRIMA.

Google Translation:

anyone is free to experiment with this circuit (God forbid ...) but if you want to spread require the citation of the source, and if someone wants to work towards economic exploitation contact me FIRST.

 

[plazma]

Schematic and top picture fixed. I had left two unused inputs floating. Now they are connected to Vcc.

 

[roy_bates]

are you saying a simple circuit like this needs permission to built?


EDIT: oh i see,if someone is making money from it they need permission?

 

[plazma]

Hi,
pay attention at the dates...
I developed a hole-less rom exchanger (4 rom banks select) on power on:
http://postimg.org/image/bcp6t3bft/
the tread is in:
http://ready64.it/forum/index.php?a...512f0f53fca&search_in=posts&result_type=posts
I explain the necessity of using an 74 HCmos.
My post end with: "chiunque è libero di sperimentare questo circuitino (ci mancherebbe...) ma se lo si vuole diffondere richiedo la citazione della fonte e se qualcuno volesse adoperarci uno sfruttamento economico mi contatti PRIMA.

Google Translation:

anyone is free to experiment with this circuit (God forbid ...) but if you want to spread require the citation of the source, and if someone wants to work towards economic exploitation contact me FIRST.

Yeah right.... You have made a similar design and posted about it in a closed Italian forum. I will make money with this and I will not ask for a permission or credit you. I made this totally independent from you using my knowledge about digital circuits

 

[MCes]

Never asked money.
Mr Meucci invented the telephone but Mr Bell patented it.
I'm not Bell, I'm not Meucci, but IF I post a circuit that I found in other place, I think is intellectually honest tell this fact.
May be that I am making a mountain from a sand grain,
but IF the circuit proposed is directly derived from mine, then I found incomprensible don't tell it.
I repeat: I don't want money, I know that is a simple circuit, but somebody explain me why I didn't found something similar posted before mine
(if somebody found it please link it to me!)

Thanks to Plazma for making diffusion of this pretty idea for switch ROM block at start up.

 

[plazma]

I did neither find anything. Not even your design. That's why I designed my own.

 

[tokyoracer]

Never asked money.
Mr Meucci invented the telephone but Mr Bell patented it.
I'm not Bell, I'm not Meucci, but IF I post a circuit that I found in other place, I think is intellectually honest tell this fact.
May be that I am making a mountain from a sand grain,
but IF the circuit proposed is directly derived from mine, then I found incomprensible don't tell it.
I repeat: I don't want money, I know that is a simple circuit, but somebody explain me why I didn't found something similar posted before mine
(if somebody found it please link it to me!)

Thanks to Plazma for making diffusion of this pretty idea for switch ROM block at start up.

I'm sure you probably did think of it but as plazma has said, it was on a relatively closed forum and it is something that could have been thought up by others maybe even before yourself (just not documented). If there is no copyrighted materials used than you will just have to accept that others may/will use it or have the same idea. All you are doing is making a switcher that isnt controlled by a switch, far from a new or unique idea.

 

[MCes]

Ok.
There is nothing to tell above.
Plazma, you was lucky buying a flip flop CMOS because the /RESTORE key has a very high impedance pull-up resistor (1M Ohm in breadbin) and a normal TTL could overload this PULL-UP and in this case the RUN-STOP/RESTORE could not work properly.
So the only kind of working chips are 'HC or 'HCT type.
In my project the second FF is used: "Clk" is connected at C64 /RESET and "D" is connected into C64 to pin 6 of tape connector (cass switch sense), the "/Q " is connected at A14 of EPROM.
2 possible keys sensed: RESTORE and PLAY (or FF or Rewind),
So there are 4 possible condition (2bit) during the power-up that will be latched into FF to feed the 2msb of EPROM (4 selectable KERNAL).


Bits that are lockable into the FF can be the JOYSTICK lines: if you press "UP" (or FIRE, or...)startup with alternative kernal, if you don't press (or no connect a joy) C64 run in default mode.......

For me selecting by RESTORE is the best!

 

[plazma]

Now the modification is ready for the short board version.
http://pasilassila.blogspot.fi/2014/06/switchless-jiffydos-for-c64-short-board.html