I am thinking about building but I have a few questions and comments before I'll be willing to start.
What's the voltage tollerence for VPP?
I don't have the LM78L08 so I'll probably use either an LM317L or LM78L05 with a potential divider.
I don't like the way the LEDs are connected up; they all share the same series resistor, wtf?
Where's the best place to buy the TEXTTOOL 40 ZIF socket
Also, I'll probably be using my own board design (I'll be using mostly SMT components to save drilling); I take it that the layout isn't too critical?
Or should I not bother and buy **broken link removed** from Craplin (which I'd rather not do since I've already got most of the components in stock)?
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Or should I not bother and buy **broken link removed** from Craplin (which I'd rather not do since I've already got most of the components in stock)?
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Thanks for the replies. What about the maximum voltage for VPP? Will voltages over say 14V damage it? I don't normally shop at Craplins but the minimum order RS and other places impose on me often forces me to; oh well, I suppose I'll have to bulk up my order with a few other supplies.
I've never seen one, but JDM programmers are well known for their problems as they require your PC to exceed the RS232 specification - JDM is the reason WinPicProg only supports parallel port programmers!.
I've never seen one, but JDM programmers are well known for their problems as they require your PC to exceed the RS232 specification - JDM is the reason WinPicProg only supports parallel port programmers!.
**broken link removed** sells a great model for 19.95 US with free shipping to anywhere in the world. It supports a large range of devices, and the single 40pin ziff socket allows any of the 18/28/40 Pin micros that it supports too be programmed
Check the posts all over the net about them, including those by the original author!. The modified JDM that Pommie has posted is a more reliable option.
For example the PIC16F84 needs 13.0±0.5 V, but you may not need to use old devices? Modern PICs generate the programming voltage internally and the !MCLR line is used as level source; some enter the programming mode with 10 V (min). I use 12.7 V for most devices.
**broken link removed** sells a great model for 19.95 US with free shipping to anywhere in the world. It supports a large range of devices, and the single 40pin ziff socket allows any of the 18/28/40 Pin micros that it supports too be programmed
Depends, do you have a desktop PC with a good serial port? If you ever intend to use it on a laptop, or with a USB-serial converter, or if you don't trust the quality of your desktop's serial port, then it's probably not a good choice.
There are SOME similar JDM programmers showing up on ebay and elsewhere that have a connector to allow you to use an external power supply for Vpp if you wish. Can't say for sure, but it would probably give you a better chance of working on a laptop or maybe even a USB-serial. Here's one example:
**broken link removed**
Really, it's a better idea to build or buy a more reliable programmer, like a parallel programmer with a good external supply, but I understand the appeal of the dirt-cheap JDM programmers to a newcomer. Eventually, many of us come around and move up to something better
Depends, do you have a desktop PC with a good serial port? If you ever intend to use it on a laptop, or with a USB-serial converter, or if you don't trust the quality of your desktop's serial port, then it's probably not a good choice.
Sorry but I haven't understood; do you mean it's a good choice to buy or build.
There are SOME similar JDM programmers showing up on ebay and elsewhere that have a connector to allow you to use an external power supply for Vpp if you wish.
google it. JDM is a style of serial programmer, which comprises most all of the serial programmers for sale out there. It's common because it's simple and very cheap, but it has drawbacks. There are plenty of threads on the forum with information on these drawbacks.
I'm really suprised they don't have converters to get 13V, all it would take is a voltage doubler with a 13V zener on the output.
On a USB programmer I have, which originally required an external power supply, I did basically that - a simple switched-capacitor voltage tripler with the 5v USB bus voltage as input and about 13v as its output.
But, if you increase the cost and size of a JDM or other style of programmer very much by adding more fancy functionality, you start to reach the point where you might as well just get something better.