Expansion Wierdness.

[CraigsBar]

Hi Guys,


Whilst testing RomManager with a Symboface for @TFM this evening I noticed some wierdness with the expansions on my machines.


The Modern expansion setup (Mother4x with Xmem, Xmass, PlayCity and minibooster) seems far less stable than the Symbiface setup.


If I use the more power hungry C4CPC with the Mother4x then 90% of the time time machine does not boot (WIth either Internal or external power to the mother4x)
If I swap it to a simple Parados Cart, or a stock Burning Rubber (Damn Menu) cart then all is well 90% of the time.


With the Symbiface connected it boot everytime regardless of cart used.


However, when the Symboface and C4CPC are connected, although the individual cart slots work fine with the Symbiface connected the C4CPC Cart Selector returns only the following message...


C4CPC card not detected
       Please reset
[attach=2]
Most odd I think


I just wondered if anyone could shed any light on this. It's not a deal breaker. The Symbiface will be heading to a small as possible PC case with the JustCPC as soon as it arrives, and I will then order a 2nd MiniBooster & PlayCity for it. I might even get a 2nd modern Multiface that I can run the buttons to the outside of the case to fill the 3 onboard slots [size=78%] [/size]

[Bryce]

Most likely a power problem. How have you got it powered up? How many Amps? One big PSU or two mixed? Switchmode or Transformer?

Bryce.

[gerald]

The Modern expansion setup (Mother4x with Xmem, Xmass, PlayCity and minibooster) seems far less stable than the Symbiface setup.
If I use the more power hungry C4CPC with the Mother4x then 90% of the time time machine does not boot (WIth either Internal or external power to the mother4x)
If I swap it to a simple Parados Cart, or a stock Burning Rubber (Damn Menu) cart then all is well 90% of the time.

Interesting. I will test that later

However, when the Symboface and C4CPC are connected, although the individual cart slots work fine with the Symbiface connected the C4CPC Cart Selector returns only the following message...

C4CPC card not detected
       Please reset

That message mean that the CPC could not establish communication with the C4CPC uC. The communication protocol involve using upper ROM 0x8A and 0x95.
The only thing I can think of is that the symbiface is doing partial decoding on the ROM pages.  But I cannot check this as I do not have Symbiface.

[gerald]

@CraigsBar

Can you run the attached cartridge with the Symbiface II attached ?
Please report anything red 

This CPR (full of pseudo random data) is used to test that the content of the cartridge is fully readable by the CPC.
3 pass are done :
- 1st pass check the page 4 byte signature (CB01 to CB00) and display the 12 1st bytes
- 2nd pass check the data in place (ie in ROM)
- 3rd pass check the data after a copy (LDIR) to RAM

[MacDeath]

who has a symbiface anyway ?

[CraigsBar]

Most likely a power problem. How have you got it powered up? How many Amps? One big PSU or two mixed? Switchmode or Transformer?

Bryce.

both Plus and Symbiface powered form a 250w ATX power supply.

[CraigsBar]

Most likely a power problem. How have you got it powered up? How many Amps? One big PSU or two mixed? Switchmode or Transformer?

Bryce.

both Plus and Symbiface powered form a 250w ATX power supply.

[Bryce]

both Plus and Symbiface powered form a 250w ATX power supply.

That should be more than enough. Then I'm with Gerald, most likely incomplete address decoding. Pity the Symbiface guys never released their schematics or code.

Bryce.

[IanS]

Get rid of or fix the Mother X4, the diodes (BAT85) aren't up to the job. I'm suprised anything works reliably with them fitted. They are only rated up to 200mA with a 0.4V voltage drop.

If you can power the X4 externally, remove the diodes and link the power socket direct with wire.

[CraigsBar]

who has a symbiface anyway ?

me... 2 actually. They have the best mouse solution to date. Still hoping we get a analogue mouse adaptor for the plus tho.

[CraigsBar]

Get rid of or fix the Mother X4, the diodes (BAT85) aren't up to the job. I'm suprised anything works reliably with them fitted. They are only rated up to 200mA with a 0.4V voltage drop.

If you can power the X4 externally, remove the diodes and link the power socket direct with wire.

but everything works with the mother x4, its the symbiface that has issues. :p

[arnoldemu]

me... 2 actually. They have the best mouse solution to date. Still hoping we get a analogue mouse adaptor for the plus tho.

The sampling rate of the analogue joystick port may or may not be enough.

[CraigsBar]

The sampling rate of the analogue joystick port may or may not be enough.

OK, how about a mx4 based symbiface compatible mouse card then?

[gerald]

but everything works with the mother x4, its the symbiface that has issues. :p

Did you had a chance to run the RomTest.cpr I posted ?

[CraigsBar]

Did you had a chance to run the RomTest.cpr I posted ?

oops no I missed that, I'll be honest here, I have been setting up emulators on my new mad catz mojo. But will do this tonight.

[TFM]

Get rid of or fix the Mother X4, the diodes (BAT85) aren't up to the job. I'm suprised anything works reliably with them fitted. They are only rated up to 200mA with a 0.4V voltage drop.

If you can power the X4 externally, remove the diodes and link the power socket direct with wire.

There is no need to be surprised that a diode shows an drop of voltage. Btw: All diodes do that. Dropping the voltage allows to consume less power, so less Amps are needed. TotO's boards can be powered with "3.3V" even. Accordingly using "4.2V" is not a problem... it is an advantage. ;-)


As a matter of fact two BAT85 diodes are used on the MX4. Therefore half the current comes from the CPC and the other half comes from the external PSU.


You can put up to four MX4 boards in a row and you will not reach more than 200mA (only 100mA will come from the external PSU).


More than 100 boards are used since 2 years and show no problems. TotO did some MotherX4 stress tests before as I know. Changing a running system? IMHO a bad idea!


IMHO: More often problems come from cat claws, milk on contacts, mosquitoes or a bad constellation of the moon.

[gerald]

As a matter of fact two BAT85 diodes are used on the MX4. Therefore half the current comes from the CPC and the other half comes from the external PSU.

That's not that simple.
In fact this would be true only
  - if the two diode are perfectly identical
  - and cpc 5V is perfectly identical to the external power supply 5V

As an example, if you consider that diodes have a fixed drop voltage (in reality it increase with current) of 0.4V
  - if CPC power is 5V. and external power is less than 5V, all current will be drained from the CPC, and nothing from the external power supply.
  - if CPC power is 5V. and external power is more than 5V, all current will be drained from the external power supply, and nothing from the CPC.

The 2 diodes on the m4x only select the higher voltage to power the extension.

[TFM]

Hmm... electrons are like water, it shouldn't be an all or none reaction. Of course there is bias if ps or parts are not identical. But does it really lead to problems? I mean 100 pieces sold and working is not bad. However power supply seems to be regarded careful in every case / hardware / expansion in general (imho).

[Apollo]

That's not that simple.
In fact this would be true only
  - if the two diode are perfectly identical
  - and cpc 5V is perfectly identical to the external power supply 5V

As an example, if you consider that diodes have a fixed drop voltage (in reality it increase with current) of 0.4V
  - if CPC power is 5V. and external power is less than 5V, all current will be drained from the CPC, and nothing from the external power supply.
  - if CPC power is 5V. and external power is more than 5V, all current will be drained from the external power supply, and nothing from the CPC.

The 2 diodes on the m4x only select the higher voltage to power the extension.

Wouldn't it be then more clever to design the power system in a way, that when the m4x is external powered to just use the extern power supply and power from the CPC only if no extern power is connected?

I am not an electronics guy besides basic knowledge so I don't know if this feasible or easy to do?

[CraigsBar]

oops no I missed that, I'll be honest here, I have been setting up emulators on my new mad catz mojo. But will do this tonight.

Ooops, by something red I guess you did not mean this.....

[gerald]

Ooops, by something red I guess you did not mean this.....

No  .
But this is expected as the bootstrap is used when the card is bigger than 160k, and the bootstrap has to communicate with the uC !
You can either try to load it with USB or wait that I post a smaller size test.

[gerald]

Ooops, by something red I guess you did not mean this.....

Smaller version. only testing 1k per rom bank. Enough to check what's wrong with the symbiface.

[CraigsBar]

OK, will run that tonight.

[CraigsBar]

Smaller version. only testing 1k per rom bank. Enough to check what's wrong with the symbiface.

Yep that one runs with no issues. Here's the results....


First X-Mem, X-Mass, PlayCity & Multiface clone.
[attach=2]


And Second Symbiface
[attach=3]


Some red appears to be an understatement.

[arnoldemu]

I am guessing the symbiface is decoding the lower 5 bits only.
So the same roms repeat 8 times I guess.