On Sun, Aug 28, 2005 at 11:13:30AM +0800, Chen Xiao Fan wrote:
> Oh yes, you add US$5 (RS232 level shifter) and another US$5 
> (power supply) and will most likely get JDM right.
> To draw current from USB port will add some money as well
> (USB connector and cable cost quite a bit in USA but may be
> much cheaper elsewhere. It is amazing that people can get
> DSL router for free after rebate from Bstbuy and other places
> but need to pay US$10 to US$20 to get the network cable.)
> 
> Why not add another US$5 (16F628 and some capacitors)
> to get a Wisp628 or better add another US$5 to US$10 to get a 
> USB version of Wisp628 or similar (all price estimated )? 
> Anyway I think the JDM argument is not of too much interests 
> in this thread anymore.

You're trying to dismiss it. I'm not going to allow that.
The MAX232 is the level shifter. I've already given you a
price of $0.69 USD. You can get power directly from the PC.
The MAX232 already has a voltage doubler that generates 9V
which is enough to provide a Vpp for flash parts.

The Wisp628 is not just a 628 and some caps. You still need to
program the part with its firmware.

While I may agree that the JDM can have its problems due to
flaky serial ports, there's no reason to believe that such
problems would exist with a proper RS-232 based level converter
at the far end.

You casually dismiss the difference between $5 and $40.
For many hobby folks, that difference can be significant.

Oh and by the way, they would still have to put together a
bootstrap programmer to program the 628.

> Now the question is about whether we need an ICD2 or similar
> debugging tools for dsPIC development. Price is not a real
> issue if another US$10 is spent. Cheapest serial only
> ICD2 can be built within budget of US$20 if time>>money IMHO
> without the supply and the serial cable (US$10?).

What about complexity then? Have you actually gone and taken a
look at an ICD2 clone? You can find one here:

http://www.nebadje.org/ICD2Clone.html

It has a 16F877A, a MAX232, and a Cypress USB interface chips
among 16 ICs and a ton of resistors, caps, and crystals.

Now a novice is supposed to somehow put this bad boy together?!
And oh by the way they have to develop another programmer to get the bootloader
into the 16F877A.

I'll have a seat and wait for that to happen.

> The hobbyists can make use of the excellent Microchip sampling
> program to get DIP package of PIC16F876/877/876A/877A to get
> this done with less than US$15 or less IMHO on a breadboard, 
> not including the power supply and serial cable. Then again
> there will be problems but you can fixed it by adding US$5
> supply or to draw from USB port (USB connectors and cables
> cost money as well).

Substituting complexity and high cost for simplicity and low cost
is a recipie for disaster.

> 
> May I ask some questions as the result of all these discussions.

Actually I will pass. I'm pretty sure you know where I stand on the
subject. But I'd be interested in hearing what other folks think.

[Questions snipped for brevity...]

BAJ
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