10 mhz Z80 CPU with CV BIOS chip, Colecovision upgrade?

[Bill Brasky]

FS: 10 mhz Zilog Z80 CPU and a BIOS chip removed from a Colecovision. Z80 was never soldered. What would happen if you replaced the 4 mhz cpu in the CV with this 10mhz cpu? Fun experiment? $9.99

 

$1.99 shipping in usa.

[ten-four]

Hi Bill.

 

What about the figure, would they so move faster or ?...

 

And the 4in1 bios, -would this work on a PAL or do it not affect ?...

 

[Bill Brasky]

Hi Bill.

 

What about the figure, would they so move faster or ?...

 

And the 4in1 bios, -would this work on a PAL or do it not affect ?...

 

 

 

I don't know if it would make everything run faster. I've never tried it. The 4 in 1 bios is only for NTSC consoles, sorry.

[PkK]

What would happen if you replaced the 4 mhz cpu in the CV with this 10mhz cpu?

 

You wouldn't notice a difference. The CV has a Z80 that is capable of running at 4 Mhz. If you replace it by one that can run at 10Mhz it will still run at the same 3,58 Mhz that the clock line says it should run at.

[Shawn]

What would happen if you replaced the 4 mhz cpu in the CV with this 10mhz cpu?

 

You wouldn't notice a difference. The CV has a Z80 that is capable of running at 4 Mhz. If you replace it by one that can run at 10Mhz it will still run at the same 3,58 Mhz that the clock line says it should run at.

 

 

An osolator crystal might be able to fix that.

[PkK]

What would happen if you replaced the 4 mhz cpu in the CV with this 10mhz cpu?

 

You wouldn't notice a difference. The CV has a Z80 that is capable of running at 4 Mhz. If you replace it by one that can run at 10Mhz it will still run at the same 3,58 Mhz that the clock line says it should run at.

 

 

An osolator crystal might be able to fix that.

 

The ColecoVision uses one clock for everything. If you increase the clock to above 3,58 Mhz the video chip will be overclocked, too, resulting in a signal no TV can display. If you manage to drive video chip and CPU by different clocks (which would require cutting traced on the CV's pcb), raising the CPU clock only, pauses between CPU accesses to graphics memory will be too short from the video chip's point of view, thus some writes to the graphics memory will be lost. This would result in graphics errors.

 

Philipp

[JamesD]

I've seen circuits that let a chip run double the buss speed while doing internal operations.

If you do some searching you might find a design that would work.