Building a lean & mean Jaycar Phoenix

[daemon123]

Thanks for the explanatory reply, I am a student, dont have credit card and live in a backward country so online purchase for me is imposible, and the only way for me is to build it myself.

Thanks again you have explained it all and simplified it more, less wires for me to worry about, just to be sure if i understood all this correctly as i am not an electronics expert. here is the modfied diagram, can u take a look at it and tell me if those are the things u suggested.




i have just done the things, will change the names of ic's later.

Here is the list of things removed
15k, 100k, D4, D5, IC2f, IC2b, S1d, IC3e, 4.7k, 470ohm, IC3c

forgot to remove the S1c from this image but will omit that as well as i think its was for that JDM

[gw1]

That looks fine.

You may want to add a 10K resistor between card socket pin C7 (I/O) and C1 (+5V). That will improve reliability and card compatibility.

The resistor on IC1 pin 10 isn't required; you can replace it with a link if you want.

The two resistors at JP1 can be replaced by a single resistor on card socket pin C2 (RST).

When you construct with a single 74HC04 IC you will need to reallocate pin numbers obviously, and you'll have a spare inverter. Its input needs to be tied to a defined logic signal: either GND, +5V, or the output of another inverter, whichever is convenient.

JP2 above needs to be a jumper link. Don't attempt to use a toggle switch with flyleads etc or the oscillator won't be stable. If you want a remote switch for clock frequency then you should follow a design like Jaycar Mk I used.

Your serial cable needs to be fully wired (all 9 pins) Male-to-Female.

If using a switchmode type plugpack then be sure to connect the serial lead before plugging in the power or you may damage IC1 and/or your PC serial port.

Have fun.

[cobra679]

I have bought 2 of these phoenix kits and every time I run out of link wire. So when you go and buy yours instead of having to go back to jaycar buy about 10 or so 0 ohm resistors looks better as well

[daemon123]

Thanks again for your reply. I have done as u said in the schemetic, but i think i will leave that resister on ic1 as i think if i dont need inverter mod then it will be required i think. Please take a look at the schemetic and let me know if all things are correctly done or not.



@cobra
I always keep UTP networking cable near, best for jumpers/links i think. Even alot of colored links

[gw1]

That looks fine.

[daemon123]

Hi,

I have managed to get all the parts. but am having trouble finding the Schotky Diode, all shops here dont recognize or have it.
one shop keep told me that he has never heard of that number and gave me this list,

1N4001
1N4004
1N4007,

and

1N5398
1N5408

he told me to either choose from them or give me volts and amps and i will give u diode. can u please tell me which other diodes can be used i mean equelent. i will try to find in some more shops but i guess they wont have it.

Edit:

I have talked to a friend of mine who repairs monitors, he said that he will try to salvage from old monitor kits, lets see what happens.

[gw1]

are a class of diode - just as zeners, LEDs, photodiodes and 'cats whisker' germanium diodes are. All decent electronics stores should know about them, and be able to order some in for you if they don't already have something in stock. You might have better luck telephoning some TV repair workshops in your area to ask if they will sell you a spare part - they will certainly know what schottky diodes are!

Alternatively you may also be able to salvage one out of the switchmode power supply in an dead electronics product - schottky diodes are a standard component in many switchmodes.

The exact part number isn't critical here. Most schottky diodes will work in this application, whether a general purpose signal one (like BAT85, BAT46, BAT48, 1N5711, 1N5712), a surface mount signal one (like BAT54, B5819W), or a power one (like 1N5819 or B220). Ideally a small signal one is preferable to a power one here, because power ones have higher capacitance which means they won't switch quite so cleanly. But for this application it's not critical.

Why do Phoenix interfaces use schottky diodes? It's because schottky diodes have lower forward voltage drop than ordinary silicon diodes. Phoenix design needs IC1 pin 9 to pull the 'open drain' I/O bus to logic low when TXD is active. The voltage levels used by most smartcards require logic "0" to be between 0 and 0.4V, strictly speaking. If an ordinary silicon diode such as 1N4148 were used the logic 0 level during transmission may be as high as 0.6 or 0.7V which for some cards may not be low enough. By all means, experiment with an ordinary silicon switching diode such as 1N4148. It will probably work OK with the cards you're using.

Another easy, low-cost approach (besides the 74LS07 used by some circuits) is to replace the schottky with a small signal NPN silicon transistor in conjunction with the spare inverter gate, like this:



As you can see I've changed the handshaking on the DB9 connector, linking pins 4,6,8. This is the most common connection for Phoenix interfaces. (The Jaycar Mk II changed things slightly because of the way they support both JDM & Phoenix modes.)