VM111 - oscillator configuration

Im having trouble configuring the oscillator settings on the K8048 board for a 16F84A chip.

Does anyone know exactly how the jumper pins JP3 and JP4 should be set for each option?

Thanks :

If I have understood your post correctly…

The jumpers are used as per the table on the PCB silkscreen. All the jumpers do, is connect the crystal oscillator to the relevant PIC socket, so for your 16F84A, which is an 18 pin PIC, you need the jumpers on JP3 & JP4.

If it’s the orientation that you are not sure about, make sure the jumper table is in the normal reading position and put on the jumpers to join the pins vertically. If you look at JP5 & JP6, you will see that it’s physically impossible to connect them wrong.

Or did you mean something else?

HTH.

Thank you for your help.

I think I mean do I have to change the jumper positions whether I’m using the internal or an external clock.

I’m coding with Flowcode V3 and the manual is very insistent that you configure the clock settings on the board exactly with the clock setup in the “configure chip” tab.

Does it make any difference?

PIC’s are very flexible and as you may already know, certain pins can serve multiple functions, depending upon how the PIC is set up within the configuration word etc. If your project becomes rather complex and you need extra pins to perform input/output etc. using the internal oscillator can gain you these extra pins.

When using the 16F84A, if you refer to the datasheet you will see that pins 15 & 16 can only be configured for an external oscillator or clock in & clock out, so if you must use an 18 pin package and require the extra pins, a better option would be a PIC from the 16F62X/16F62XA family.

So back to your question…

The K8048/VM111 is a PIC programmer with additional hardware to perform basic development using the hardwired switches and LED’s. The oscillator/capacitors are only on the board to allow you to develop/run your simple program and serve no function during programming. When looking at pure programmers, such as this one: feng3.cool.ne.jp/en/pg5v2.html you will note that there is no oscillator on board, as it is not required.

The programmer board does not care what your code contains, it only injects the code to your PIC, so leaving the jumpers on/off doesn’t matter. Mine have been left on since I built the board.

I haven’t used Flowcode, but as with any software used for development, you must correctly set up the config word for the target board you will be using. If the example program specifies a 4MHz oscillator and your target board has a 20MHz oscillator, you can assume that your program will run WAY faster than it was intended. Relevant, but I’m rambling now…

For programming, no.

Brilliant thank you! You are indeed a sainted man! Now where’s that d**n board!