can someone help me check?

[mister_e]

The use of a diode to reduce the voltage is not the best solution if the target circuit don't need much current. In this case, the voltage drop on the diode will be less than what you wish.

SO, your PIC is probably dead now and short. This is why your DIODE comes HOT.

You should double check your crystal connection also.

What is between the PIC and the Motor?

[saturnX]

do you know how glad i am to see your nick online on the forum! is there a manual way of testing if the chip is dead? i don't get you on the part of the where you asked whats between the motor and the chip. If i get you correctly there isnt anything except a link to RB0 from the chip to the motor. Remember the codes i posted on the other discussion where u helped me convert to basic. yeah that is the codes and the schematics are attached here.

you reckon i should get a batch of fresh new chips? oh the other question which i forgot to mentioned (maybe i did) in the first post, is there a difference in the type of chip it uses. In the book it says 16F84 but when i got this batch from the robot store where they sold the parts to make this robot, they sent the 16F84A chip.

[mister_e]

OK now we have two reason to believe that the PIC is dead now. As the motor need more than 25 mA, you blow the I/O and the PIC. You MUST use a driver (MOSFET, Transistor) to drive your Motor.

There's not really a manual way to Test if the Chip is good or bad BUT, try to erase it and reprogram it again. There's lot of chance that you'll get some error message from your programmer software.

[mister_e]

16F84 or 16F84A... the one you have is a newer version. There's no big difference. But if you want to have the truth, there's probably some Migration document or errata on this chip on the Microchip website.

[saturnX]

i just so happen to have just erased and reprogramed it but i didn't get any errors when it was doin so. i even got it to verify the burn to the chip and it came back OK including the blank check.

when i disconnect and reconnect back the diode the motor jumps to life for 1 second then nothing.. the diode heats up from there. but have a look at the original schematics from the book (attached drawing.jpg) the author did not include any transistors in between the chip and motors.

[mister_e]

Yeah i see but you must have it. As your pin is probably dead, try with another i/o it will work for a few, then blow again.

Do you have any spec of the motor you use?

Do you have some Npn, PNP transistor or mosfet on hand? If so wich ?

Double and triple check your Crystal and capacitor connection...

[saturnX]

no i don't have any at hand right now. the electronic shop is 5mins from my house. i want to ask about the crystal and capacitor connections... have a look at this website schematics: http://home.planet.nl/~j.havinga/servo/servo.htm
how come the crystal is and capacitors are only hooked up to pin 15 where as in my book it says it has to be connected to both 15 and 16. can share some light on this?

servo motor: HiTEC HS-322HD (recommended by the author)
Class: Standard
Digital: No
Programmable: No
Voltage: 4.8v or 6.0v
General Specs:
- Bearings: bushing
- Gears: Karbonite
- 60° speed: .19 sec @ 4.8v
- 60° speed: .15 sec @ 6.0v
- Torque: 42.00 oz/in @ 4.8v
- Torque: 51.00 oz/in @ 6.0v
-- 1.57 x.79x1.46 inches
- 1.52 ounces


In the book the author incorporated the diode to keep the power at least consistent at around 5.3v to make it possible to run the motors.

[mister_e]

ARGH forget me, i didn't notice it was a ServoMotor. So the i/o current is not a problem now.

While i don't see the same thing as you about the only one pin connection... it is connected on 15 and 16.

BTW, do something. Remove both capacitor, crystal and their jumpers, and sit the crystal directly on pin 15 and 16. It will work without the cap... on bread board only.

Next thing, did you set the osc mode to HS in your programmer software???