Pic all write 010c pic doc Worlds most easy PIC-Programmer.pdf

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Worlds most easy PIC-Programmer.
Easy PIC Programmer.
This page describe how to make the most easy PIC Programmer.
The Programmer do need external power supply (stabilized). And it use only one resistor.
The programmer has computer ground as global ground. It is possible to let the programmer stay in a
circuit connected to some of the pc's ports (e.g. LPT or COM) while programming, and it is not a
problem with main-ground connections on both programmer and PC.
Schematic:
5V power
| supply (or 4.5V battery.)
|
-
R| |100 ohm (down to 56 ohm).
| |0.5W
-
|
14|
-------
| VDD |PIC16C84
|
|
|
|
| MCLR|------- TxD (2)
|
|4
|
|
+--- DTR (20)
|
|13 |
| RB7 |---+--- CTS (5)
|
|
| RB6 |------- RTS (4)
|
|12
|
|
Connect directly to
| GND |
serial interface.
-------
5|
+---------- GND (7)
|
| power
0V supply
file:///D|/Electronice/Programe/Microcontrolere&PIC/Pic...0010c/pic_doc/Worlds%20most%20easy%20PIC-Programmer.htm (1 of 3)08.08.2003 03:51:56
Worlds most easy PIC-Programmer.
Clamp diodes:
RS232 is current limitted, and clamp diodes inside the PIC are used to limits the input voltage to the PIC
range, but when using the clamp diodes may the PIC16C84 sometimes latch up. Resistor R eliminates
risc of latch up. And it also protect the PIC16C84 against too high currents inside which minimalize or
eliminate latch-up possibility.
In fact, the clamp diodes to Vdd is not diodes, but transistors, and about 80% of the current flows into
ground. Because of this, are Vdd not to be pulled higher than Vdd+0.5V, even all the inputs pulls high.
(at 20mA from the inputs, flows max 3-5 mA to Vdd, and cause about 5.4V). The decoubling capacitor
and LED's inside the power supply does that the power supply keep the 5.0V at the output. (The duty
cycle of the programmer does that it pull more current out, than it lead into the supply, and then a
stabilized power supply has a decoubling capacitor, that makes the power positive out from the
regulator.)
Latch-up prevention:
Since the processor makers typical not reduce the power into the chip and makes it latch-up free, we do
it. If a circuit need to be latch-up free, it must never hang in latch-up condition, even if we pull in the
pins above any accepted level in any condition. As soon as the condition that increase latch-up
possibility is over, should it work again - else is it not truely latch-up free.
How to do it:
Reducing to a maximum current into the power pins, do eliminate latch-up risc. If the chip has substrat
contacts, it will need a current to be over a high level - and only if the maximum current is above this
level, will the Vbe for the transistors be high enough to make it hang.
Sometimes signals never folow the processors specifications, because wires inlclude induction and cause
high currents. But designers of chips know about these problems - and makes the capacities in the chip
high enough to avoid the riscs. (hopefully)...
If wee need to guarentee latch-up free condition exist, then it is possible to do without current limitting
components in the chip, but to do it external using a resistor in Vdd/Gnd.
Current limiting:
The RS232 outputs is current limited, and it do typical not exceed +/- 15mA. PIC's handle up to +/-
20mA. Current in the clamping diodes may cause latch up and to prevent this effect we do need the
resistor R to reduce the current from power supply. The typical Vdd current is about 3 to 4 mA, and the
voltage drop on 0.4V is ok. The power resistor reduce maximum Vdd current to about only 50mA and
then protects the PIC from meltdown if it is inserted in a bad way.
Download PIP-02 beta driver, JDM84V33.ZIP (5K).
Download PIC16C84 utilities, PGM84V34.ZIP (38K).
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Worlds most easy PIC-Programmer.
The utilities is inclusive source.
Extra lowcost for PIC16C84 only.
Simple programmer for PIC16C84 and 24Cxx only.
References:
q
q
q
q
q
PIX Programmer.
PIP-02 software.
Original PICBLASTER / Erik Herman.
COMPIC-1 serial PIC and I2C serial EEPROMs programmer, designed by ORMIX Ltd.
ICPROG Windows software, version 0.9b02, beta. May not work. But works.
Links:
q
q
q
q
Microchip Net resources by Alexey Vladimirov.
David Tait, PICLINKS.
Malte Kiesel, additional info and software for the PP2.
Jacob Blichfeldt, smartcard programming.
How to make a processor with the delay between instructions less than a half nano second in standard 1u
CMOS. (GHz instruction frequence.)
Z80 trick: Use RESET, NMI and CLOCK to bootload a romless system (RAM only).
I am sorry, but I am not able to use money on keeping this page active. It will not be updated.
Refresh it
|
Systems Without Memory
|
Running unknown look-up's
|
Boot
|
DRAM
|
CPU
PQ-Programmer
|
Adv. PIC Programmer
|
Extra lowcost Programmer
|
Hardware Simulator
|
Files
I am sorry, but it I have stoped to answer e-mails.
Please update your bookmarks, new location is
http://www.jdm.homepage.dk/easypic.htm.
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