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JDM for 16F84A-20I/P and 16F874-20i/P?

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egh01

New Member
Hi,
I have two questions:

1. Can a JDM programmer be designed so that it can program both 18, 28 and 40 pins PICs? If it can be done, do I just have to make room for three different DIL-sockets and ignore or ground the extra I/Os on the PICs with larger pin numbers? Or has someone built a simple adapter for this purpose?

2. Which is to prefer, JDM PIC-Programmer 2 or 3 if I first of all want to program 16F84A-20I/P and if it can be done, 16F874-20I/P?

Thanks in advance
 

tommyc2000

New Member
44444

1. Yes it can. Bulid the one for 18 pin first, then make adapters for the 28 and 40. the EEProms PIC's use only 5 pins when programming.
RB7, RB6, VCC, GND(VEE) and /MCLR

2. JDM is the simplest, easiest and the cheapest (under 5 bux) programmer to make. Programms ALL EEProms MCU's(16c84,16f84,16f87X)
 

tommyc2000

New Member
3333

i made the one that's in the first picture, jdm2 i guess and I didn't even do it on pcb, i got it all jumpered and it's just perfect. pin 20 jumper means that, the connection from that pad on the pcb goes to pin 20 of the serial port of the PC


p.s. by the way, if you noticed jdm3 has 6 serial lines to program the pic, and more parts, which simply means it's little more complex than jdm2, although it is still under $5 bux to make it, so you make up your mind which one you want to make
 

egh01

New Member
I have one more question about the JDM programmer (JDM 2, the one on the top). What capacitors have you used? Jens gives two different voltage-values for C1, at one point he says 100uF/40V and later he says 100uF/25V, does it matter which one I choose?
 
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