Wanting to get started with the Propeller chip, but need advice

eagletalontim

I currently sell a product that uses the SX28 DIP but since it is at the EOL, I need something to convert to soon. After finding the propeller, it looks like I may be able to use this in my applications. The product I sell runs in vehicles and controls two solenoids which can draw up to 5 amps each. What I am looking for is to convert my circuit to work with the Propeller and find an EEPROM that is large enough to store a new program to run my product. The problem is, I have no idea where to start.

First, I know I will need some kind of soldering station to be able to solder the SM Propeller. Working on getting one now, I just hope it is the right kind.

I also know I need to redesign my PCB to fit the propeller to the board along with an EEPROM. One question is.... can surface mount components handle the current for the regulated voltage side? Right now, I have a 1k resistor that goes to the base of a small switching NPN transistor which has a 1k going from the emitter to a TIP42 PNP transistor which controls the +12v side of the solenoids since they are already grounded to the car. The thing I am worried about is heat. With lower voltages, I am wondering if that will cause problems on the higher voltage side switching components since they may not be fully activated with the current required.

What EEPROM would best match my needs even if it is a little overboard in memory space. The more the better but the smaller the better as well.

Last but not least, I will need some time of voltage regulation, but I have no idea what to use to run the Propeller and an EEPROM since the voltage is 1.7 volts lower than the SX power requirements.

Thanks for any and all help in advance!

mctrivia

Surface mount resisters will handle about 1/10w in 0603 size.

Some surfacemount parts can handle many amps. I have a fireworks board that handles 15a all in surface mount.

Use a 512kbit eeprom almost same piece as minimum needed.

For surfacemount work I I use a convection toaster oven.

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mctrivia

Use a switching regulator to drop voltage.

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eagletalontim

would you happen to have a diagram to use the switching regulator on the Propeller? Since I know enough to be dangerous, I need help getting started with the design.

I have some of these : 4KB EEPROM 24LC32A : in my inventory of parts. Is this enough to hold as much as an SX28 or more? I also see Parallax has some 64KB EEPROMS as well and they are SM.

mctrivia

i listed kila bits.

you will need 32KBytes minimum for prop. 64k if you want to use my bootloader program.

for ideas on how to make switching regulator check my infa prop out.
http://forums.parallax.com/forums/default.aspx?f=25&m=388636&g=389945#m389945

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T Chap

You can solder the Prop QFP with a fine tip pencil, just get a good magnifying lense and light. Same for the eeproms.

eagletalontim

what about the heat that the cheap radioshack soldering irons put out. isn't that too much heat for the chips and one mess up would ruin the whole chip or surrounding pins? I figured if I got a decent soldering station, I would be ok since I can regulate the heat down enough to be safer instead of burning up the first 20 chips I order I can't seem to open the schematics. I use ExpressPCB as my board editor. What program do I need to open the ones you posted, mctrivia?

StefanL38

The size of EEPROM you can use for a program directly is 32kB.
If you describe in detail what your product is doing we can estimate if 32kB is enough.
Right from the hip I guess yes it is enough.

If you can provide datsheets of your transistors it's possible to analyse if it ist working.
Or you just do a practical test. Connect the 1k-resistor of the base with an adjustable voltage-regulator like a LM317
and reduce the voltage stepwise and measure the current flowing through the soleniods and measuring the voltage-drop across the
emitter-collector trace of the TIP42. If this voltage-drop stays the same the TIP42 is still supplied into full saturation. And this means
same situation as with 5V.

From the datasheet http://www.fairchildsemi.com/ds/TI%2FTIP42C.pdf I can see
at 6A collector-current the CE-saturation voltage is 0,46V and the base-emitter-saturation-voltage is 1V.

What current do you measure at the base of the TIP42 when driving the circuit with 5V and a collector current of 6A

best regards

Stefan








There are fixed voltage-regulators for 3.3V which match exactly with the propeller

T Chap

I have a radio shack soldering iron. My older supposed good brand died and I was in a jam one day and got a radio shack one with a dial for temp. It goes to 830F and I have soldered chips many times at that temp and never had a problem. Of course you can't just sit there with high heat on a pin all day.

James Long

eagletalontim said...
what about the heat that the cheap radioshack soldering irons put out. isn't that too much heat for the chips and one mess up would ruin the whole chip or surrounding pins? I figured if I got a decent soldering station, I would be ok since I can regulate the heat down enough to be safer instead of burning up the first 20 chips I order I can't seem to open the schematics. I use ExpressPCB as my board editor. What program do I need to open the ones you posted, mctrivia?

Just to clarify.....heat is a quotient of time. The less time you want it to take, the more heat you need. At least to a point. You can get enough heat to kill a chip very quickly.

The problem with a Radio Shack soldering iron is the lack of tips. You need an angled tip, not pointed, nor chisel. The right tip can make or break the operation. It needs to be from 1 - 2.5 mm in size.

I very rarely use anything but flux, iron, and solder. If I have problems with bridging, I move to vertical soldering (stand the board on edge). This will help with bridging.

I have done 100 pin fine pitch LQFP's and with the right flux, and tip, it is not that hard. I rarely use solder wick.

James L

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James L
Partner/Designer
Lil Brother SMT Assembly Services

Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits. Learn to build your own Gizmos!

mctrivia

Either eagle(cadsoft.de)

Or a gerber viewer

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mctrivia

Actually if you always use the right tip then temp is based on solder type

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24 bit LCD Breakout Board coming soon. $21.99 has backlight driver and touch sensitive decoder.

Cluso99

You need ot understand the basic propeller circuit - see the protoboard schematic. You can use the AT24C256 eeprom although the AT24C512 is twice the price and only marginally dearer. The prop requires this eeprom (or compatible) for booting user code. You require extra software to access above the 256 (32KB).

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)
· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBladeProp is: www.bluemagic.biz/cluso.htm

hover1

I just purchased a Radio Shack·Digital Soldering Station:
http://www.radioshack.com/product/index.jsp?productId=3132686
I comes with one tip and no replacements in the store or online. After investigating further, I found it is·a Madell model AT201D, and there have 18 different tips available for purchase from thier website:
http://www.madelltech.com/Soldertips.html
Now this makes this $80.00 soldering station·quite useful.
Jim

James Long said...




The problem with a Radio Shack soldering iron is the lack of tips. You need an angled tip, not pointed, nor chisel. The right tip can make or break the operation. It needs to be from 1 - 2.5 mm in size.

I very rarely use anything but flux, iron, and solder. If I have problems with bridging, I move to vertical soldering (stand the board on edge). This will help with bridging.

I have done 100 pin fine pitch LQFP's and with the right flux, and tip, it is not that hard. I rarely use solder wick.

James L

eagletalontim

Cluso99 said...
You need ot understand the basic propeller circuit - see the protoboard schematic. You can use the AT24C256 eeprom although the AT24C512 is twice the price and only marginally dearer. The prop requires this eeprom (or compatible) for booting user code. You require extra software to access above the 256 (32KB).

I found the protoboard for the propeller and it seems pretty similar to the SX connections except the power regulation circuitry. Is it required to have the 2 voltage regulators to step down the power to 3.3v? Having to add so many different additional components makes the production of the board more expensive on my end. Current cost for my design if ordered in quantities over 20 is about $25 each. I did notice that most SM components are cheaper though.

I was looking at this EEPROM : http://www.parallax.com/Store/Components/IntegratedCircuits/EEPROM/tabid/614/CategoryID/79/List/0/Level/a/ProductID/453/Default.aspx?SortField=ProductName,ProductName and I wonder if this would be just right for me. Since you stated I have to have additional code to read anything over 256k, I should probably stay away from that unless needed. Since this EEPROM is SM, it would probably fit better in my application since I would like to design my product into something smaller and better.

Before I go ordering 100 of these chips, would the Propeller protoboard come with everything I need to get started if I got the Prop Plug as well?

eagletalontim

I went ahead and ordered a Protoboard and the Prop Plug just to get started and see what all I can do with it. Hopefully I can get this sorted out soon [noparse]:)[/noparse]

Mike Green

The Protoboard has regulators for both 5V and 3.3V because Parallax wanted to support 5V devices on the Protoboard. It also allows more flexibility in terms of input supply voltage because the regulators share the power dissipation to some extent. If you only need 3.3V, then you could use just a 3.3V regulator. Do be careful about heatsinking if you have any significant current usage (a couple of hundred mA or more) and an input voltage much more than 6V.

The EEPROM you showed will not work. The Prop has to have an EEPROM with at least 32K bytes of storage like the AT24C256 or Microchip 24LC256. If you need to store any significant amount of data or another program (overlay), you'd need an AT24C512 or Microchip 24LC512 or possibly an AT24C1024B or Microchip 24LC1025.

The Protoboard does come with everything you'd need to get started (other than a PropPlug) assuming you already have a power cube. The USB version includes the PropPlug circuitry on-board.

eagletalontim

I do not have a Power Cube..?? What is this and it is necessary? When programming the SX chips, I use the SX Key and a 6v power supply.

mctrivia

He is talking about your 6v supply

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24 bit LCD Breakout Board coming soon. $21.99 has backlight driver and touch sensitive decoder.