OESF Portables Forum

Everything Else => Sharp Zaurus => Model Specific Forums => Distros, Development, and Model Specific Forums => Archived Forums => 5x00 Hardware => Topic started by: jace48 on June 17, 2005, 04:32:20 am

Title: Serial Cable For 5500
Post by: jace48 on June 17, 2005, 04:32:20 am

Hello all,

I got my Zaurus connector from Fivestar.

Before I jump to build my serial cable this weekend, I would like to know whether just a pin mapping will suffice or do I have to build a circuit to do the logic translation?

I plan to use this cable to connect to serial port of CDMA phone and regular sync work

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Title: Serial Cable For 5500
Post by: omega on June 17, 2005, 06:04:12 am

Be wary... You can't just connect the pins... the zaurus is 0v and 3v  instead of +9 and -9...  I suggest you use a MAX3232 and power it from the same port...  there is a document around showing the pinout of the sharp connector on this forum.

If you're stuck i'll try to help - I have built an interface to the Z.

Title: Serial Cable For 5500
Post by: jace48 on June 17, 2005, 08:50:25 am

Quote

I suggest you use a MAX3232 and power it from the same port... 

Hi,

Do you have some refrence circuit that I can use?

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Title: Serial Cable For 5500
Post by: omega on June 17, 2005, 10:21:12 am

Hmm... my reference circuit is just a couple of transistors...

Lookup the datasheet for the max3232... www.maxim-ic.com

Basically there is 3v out on that serial io connector, and that SHOULD (no guarantee) be able to supply the MAX chip no problem... as there is something similar in the normal active cable.   Then you have four small capacitors to connect to the max3232 for stepping up the voltages.  Then you wire up the pins you line. tx to rx, etc.

DO NOT, I repeat DO NOT blame me if you blow up your zaurus - which is entirely possible if you accidently solder two pins together, etc.

good luck,
omega.

Title: Serial Cable For 5500
Post by: marcan on June 24, 2005, 10:59:37 am

Careful though. I've worked with MAX232 and microcontrollers - the MAX232 maps -12V to +V and +12V to 0V. But the Z works the opposite way. So you need to add some logic inverters. Or transistors. I have wired the Z to a PIC microcontroller for a hardware project, and that's how I found out that everything was reversed. A couple transistors were fine for my project.

Title: Serial Cable For 5500
Post by: omega on June 27, 2005, 04:05:38 am

marcan, You are correct as far as I remember about the Z - pic needed the signal inverted, but the Z - PC will work fine...