Newbee with homework board question

Greg455

Hi everyone,

I'm new to the forum and have a programming question if someone can help.· My question is this: I have the parrallax homework board I'm using as a prototype board for circuits that run with the brains being the PIC chip.· Question is can you program another pic chip on the homework board or through the homework board so as to build the·Prototype circuit off the homework board with a homemade PCB?· Any answers........

JSWrightOC

You will need to purchase a BS2-IC or the BS2-OEM to build your project with. If you choose to build with the BS2-IC, simply include a 4-pin header to connect to pins 1, 2, 3, and 4 of the BASIC Stamp. Alternatively, you can wire these pins correctly to a D9 Female connector, which can be used for debugging, PC communication, as well as programming. the BS2-OEM (sold either as a kit or fully assembled) module already has this D9 Female connector on it. Those are probably the two simplest options. The schematic for wiring the D9 connector to the 4 pins of the Stamp can be found here.

Hope this helps!

*edit*

I probably wasn't 100% clear in my hasty response. To answer your question, no you can't program a Stamp on the HomeWork board, unless you use it for the prototyping space only and wire a serial cable up to it. The serial connector on the HomeWork board is hardwired to the interpreter chip installed on the HomeWork board, so you can only program it. If you wish to do some prototyping with Stamp modules, consider getting the Board of Education, which takes a BS2-IC module that you can program in the BOE, then remove and install in your circuit. More than likely, though, you'll want to have the serial interface on your custom PCB for debugging and future software upgrades, even if it's only a 4-pin header. There are also other more elaborate development boards available.

Post Edited (JSWrightOC) : 9/24/2007 11:55:43 PM GMT

Mike Green

It sounds like you want to program a PIC chip using the Homework Board's Stamp to help. The simple answer is "not really". The Stamp is a specially pre-programmed PIC and the programming connections don't actually reprogram it. The PBasic interpreter in the Stamp's PIC uses the serial input to download an interpreted program into the EEPROM that's also on the Homework Board. The PIC's program memory is not changed. I believe you can write a program using the Stamp that reads data from the PC and manipulates some of the I/O pins such that the Stamp will program an external PIC, but you probably will need some additional circuitry for most PICs and the process will be slow and not readily compatible with the PIC assemblers and compilers. You're much better off buying an inexpensive PIC programmer like the PICkit2 that comes ready to go with PC software.

Greg455

Thanks Mike and JS,

Mike that's exactly what I want to do, is program an external Pic chip which you are calling the Interpreter. the reason being is to use the homework board as the prototype platform with the programming associated with the interpreter and then transfer the circuit to a homemade PCB with new PIC IC and EEProm, crystal and external devices along with the circuit built on the prototype area of the homework board, saving my homework board for more prototyping. Is this making sense? I think your right on just having to buy or build a PIC programmer to do this.

My thinking is if you use a PIC programmer, you use your computer desktop or laptop to compile and dump through a serial cable to the programmer circuits, why can't you do the same through the homework board to send the code to the PIC chip on the protype area of the homework board with some code?

JSWrightOC

I'm a little bit confused...

You have created a circuit on your HomeWork board that uses the circuitry (PIC chip, EEPROM, etc.) that is built into the HomeWork board, and you want to transfer these components to a custom PCB, right?

The PIC chip on the HomeWork board is custom programmed by Parallax with the BASIC Stamp code (which is their Intellectual Property) and then it reads PBASIC commands out of the external EEPROM to execute program code that you write and download to the HomeWork board. When you write a PBASIC program in the Stamp Editor, it gets downloaded to the EEPROM (not the PIC) and then executed by the "Basic Stamp" code that is hard-programmed into the PIC. So at this point the PIC no longer behaves like a PIC, it behaves like a PBASIC interpreter.

Are you trying to take a bare PIC chip and program it using the HomeWork board as a programmer, or are you intending to replicate the circuit which you have built on your HomeWork board?

Mike Green

Greg,
As I said before, you can use the Stamp on the Homework Board to send code to a PIC chip on the breadboard area. There are two problems: 1) Most current PIC chips require a switched power supply, usually 12V, for programming (Vpp). This is not hard to supply, but you have to be careful, otherwise you can destroy your Stamp. 2) The Stamp is slow compared to the way a PC would be used for PIC programming.

So, it's doable, but, other than as a demonstration of concept, it'd be better to get something like a PICkit1 or PICkit2.

allanlane5

Greg:

What they're calling the "interpreter chip" is NOT a 'plain vanilla off-the-shelf PIC chip'. An "interpreter chip" is a PIC chip that's been pre-programmed (before you get it) with the Parallax run-time code. That run-time code is Parallax proprietary. So if you go to Digikey and buy the identical PIC part that Parallax would sell you, it WON'T have the "interpreter" code in it, and WILL NOT work as an OEM BS2.

Now, to program a 'stock' PIC, you need some way to interface the In-Circuit Programming (ICP) circuitry of the PIC chip. MicroChip sells a kit for this which is not too expensive.

You CAN build your project using the OEM BS2 -- as long as you buy the PIC-based "interpreter chip" from Parallax, to insure it's pre-programmed with the Parallax run-time code. In that case, it's not very difficult to program the external EEPROM that holds the user program using the OEM BS2 from your PC.

It does sound like your original scenario -- use the Homework board to program an off-the-shelf PIC -- is NOT going to work.

Greg455

Thanks again everyone for the input.

I'm getting the big picture now. I'm building an ignition circuit for a 2 cycl engine. The basic program itself sets up the timing for dwell and handles the Hall Ic input.
When I bought the homework board I didn't realize the PIC on it was programmed at the factory for basic interpreter, I thought that the software compiled it into machine language that the PIC could process on it's own, or other words I thought PIC's must of had it's own built in BIOS. So yes your right I was under the impression I could buy an OEM PIC 16C57 ( from Digi-key or others) and it would understand my basic code that I programmed for my ignition circuit.

See Forums do help you get information...... [noparse]:)[/noparse]

JSWrightOC

Glad we could help - Be sure to pick up a BS2-IC or BS2-OEM, or the parts to build an OEM, and you'll be all set!

If you find you need more performance, you can also look at the BS2sx, BS2p24, and the BS2px. Have fun with your project!

Chris Savage

All is not lost. You can still purchase the pre-programmed interpreter (as mentioned) and connect an EEPROM and resonator to it and you have a BASIC Stamp (including support components). The total cost can be under $15.00. We know of OEMs who use a BS2 OEM to program the EEPROM then plug that into their final circuit. I hope this helps. Take care.

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Chris Savage
Parallax Tech Support

Greg455

Thanks Chris and JC,

I've been looking at the BS2-OEM, I think that will work out perfect for what I was trying to do. I'm going to order the Kit. Looking forward to putting it together and with the Dip sockets I'll be able to program and replace. Nice thanks....... [noparse]:)[/noparse]

Chris Savage

Bear in mind the ‘OEM’ configuration I referred to is not using the BS2-OEM kit we sell. That is designed to demonstrate the construction of the BASIC Stamp using discrete components. I am referring to just including the necessary components for the BASIC Stamp functionality on your own board. Take care.

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Chris Savage
Parallax Tech Support