Stand-alone SX requirements.....
MyYz400
Posts: 11
I'm currently using a Parallax developing board for the SX. I would like to create my own PCB to run the SX on. How-ever I'm having difficulties finding schematics for a simple SX PCB setup.
I'm not an electrical engineer so most common practices still aren't obvious to me.
I spoke with someone who has done circuit design, and he recommended few things, but I wonted to run it by people who have done this before. Here is what he suggested
-Always use a voltage regulator, regardless if using a 5V power supply. (for safety it sounds like)
-Put 0.1u and 10u caps close to the IC's Vdd as possible. (electrolytic? or no)
-Use large ground planes to fight noise (ok, makes sense)
-Put power on bottom plain, and signals on top (is this necessary?)
My other questions are:
-does the SX key really only use the OSC1/OSC2;Vdd;Vss? Does the IC get programed through the OSC ports?
-Can I just use the interal clock of the SX? Does this mean I need to use the external R/C circuit?
I'm just trying to get an idea of what is needed to run the SX out-side the tech board. Anyone know of some articles or schematics to help show this?
Thanks
MyYz400
I'm not an electrical engineer so most common practices still aren't obvious to me.
I spoke with someone who has done circuit design, and he recommended few things, but I wonted to run it by people who have done this before. Here is what he suggested
-Always use a voltage regulator, regardless if using a 5V power supply. (for safety it sounds like)
-Put 0.1u and 10u caps close to the IC's Vdd as possible. (electrolytic? or no)
-Use large ground planes to fight noise (ok, makes sense)
-Put power on bottom plain, and signals on top (is this necessary?)
My other questions are:
-does the SX key really only use the OSC1/OSC2;Vdd;Vss? Does the IC get programed through the OSC ports?
-Can I just use the interal clock of the SX? Does this mean I need to use the external R/C circuit?
I'm just trying to get an idea of what is needed to run the SX out-side the tech board. Anyone know of some articles or schematics to help show this?
Thanks
MyYz400
Comments
A cap between Vss and Vdd (0.1uF).
A 10K resistor from MCLR to Vdd. (This is important).
Yes, the SX uses the OSC1 and OSC2 pins to be programmed. If you use the internal clock just leave OSC1 and OSC2 alone (except for the programming connections).
Bean.
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Does that byte of memory hold "A", 65, $41 or %01000001 ?
Yes it does...
·
www.leonheller.com/SX28/SX28(Page1).pdf
I used the Fluffy programmer with it.
Here is the PCB layout:
www.leonheller.com/SX28/SX28_PCB_layout.GIF
I can upload the artwork for you to make your own PCB.
Leon
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Amateur radio callsign: G1HSM
Post Edited (Leon) : 11/24/2009 8:21:47 PM GMT