The Propeller Platform is a Parallax Propeller based cpu module using
Gadget Gangster Platform board form factor. It is a standard straight forward Propeller design
with the following features:
comes with socketed 5 MHz crystal (16x pll - 80 Mhz run speed) which can easily swapped for
a faster crystal
comes with both EEPROMs as 24LC512, 64KB each, leaving the user 96KB for program use
user supplies 7.-12v dc, on board circuitry gives clean 5.0 amd 3.3 VDC
can be programmed via RS232 using Wulfden's P1, or via USB using
Wulfden's BUB, or via a Parallax USB2SER or Prop Plug
You are going to need to download either the Parallax Propeller Tool or the BST cross
platform (Windows, Mac, and linux) propeller tool suite from
Parallax Propeller software page.
Propeller Platform
Complete kit with PCB, Propeller chip, two 24LC512 EEPROMs, Platform connectors, power ciruits, etc
Nick, at Gadget Gangster, has made a great video on How-To
assemble the Propeller Platform. I highly recommmend you spend the 10 minutes or so to load and view this video.
Having now built five of these board over a fairly short interval, I have few suggested changes to
the process that I have found makes it easier. They are below ... sorry, Cecil B. DeMille I am not ... still pix and text!
The comments below may seem lacking in detail if you do not view the video first
There are several variations form the schematic.
VR1 will be an LD1086V50
the 4.7 uF Tantalum will be at C5 and the 0.1 uF will be at C4
U2 and U3 will both be 24LC512 (64 KBytes each)
R2 is now a 330 ohm resistor (orange-orange-brown)
The first item installed should be the crystal socket. Break
out and clean the machine pin sockets from the plastic, then insert them through the pcb
and turn it upside down on a flat firm surface. Align them straight up and solder.
There are five 1/8 watt resistors, labeled, Left to Right, R1 through R5.
R1 - 1 Kohm (brown-black-red) - Vin LED
R2 - 330 ohms (orange-orange-brown) - 5V LED
R3 - 220 ohms (red-red-brown) - 3.3v LED
R4 - 10 Kohm (brown-black-orange) - I2C pullup
R5 - 10 Kohm (brown-black-orange) - I2C pullup
Now is the best time to insert and solder the small 0.1 uF monolithic cap
(marked "104"),
before you place the two 8 pin and one 40 pin DIP sockets. The sockets supplied are 3M dual wipe
sockets that have a kink in the legs so that they stay in the holes when you turn the
PCB over to solder. Now also would be a good time to insert and solder the 4 pin right angle
programming header. If you are using a Prop Clip(r) this header is not needed. If you are using
an older Parallax USB2SER insert into the holes marked as such. If you are using a Prop Plug(r) or
one of my Wulfden Prop-BUBs insert the header into the holes marked PLUG.
Let's get the rest of the capacitors. The 4.7 uF Tantalum is polarized.
When the writing on the side is facing you. The positive leg is to the right and the negative
leg is to the left. The negative goes to the ground hole which is to the left. The three 47 uF
electrolytcs are clearly marked, match up to the plus sign on the silkscreen. Insert the three
LEDs as shown. Remember on the electrolytics and the LEDs the short wire lead goes to negative.
Let's do the hardware. Insert, bend the leads a little and solder the reset button.
Now decide whether to use the terminal block or the 2.1mm coaxial power connector. Then insert and
solder. Now, the switch. and a big decision. PCB switches of this size are rated at only 250 ma. The
LD1086 regulators here when used with the heatsinks I include, are good for 1.5 A. The traces are good
an amp. I have run over a half amp for an hour through the switches, the official rating not
withstanding. You may want to consider leaving out the switch and using an 18 ga jumper in its place
and putting a heavier switch in the power line. If you do use the switch the outer two of the three
legs need to squeezed in a little towards the center pin.
Finally put on the voltage regulators, 5V on the top and 3.3V on the bottom. Align and
bend the legs, then take some thermal heat sink compound (Radio Shack p/n 276-1372) on the heat sinks and
slip one under each regulator and bolt them on bringing the screw up from the bottom. Once they are all
aligned solder and clip the leads.
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