From: Michael du B. <wic...@gm...> - 2013-11-27 21:01:07
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Turns out it was an issue with wiring the reset pin, although I will investigate using _MCLRE_OFF, but it doesn't hurt in my usage to not have the RA5 pin available. I'm getting the high programming voltage from the PicKIT2. Thanks for the assistance. (And I will probably reverse the drives of my LEDs to be sinking to the pic instead, thanks for the tip). On Sun, Nov 24, 2013 at 6:50 AM, Richard Gray <ri...@re...>wrote: > These are just some thoughts that spring to mind, so don't take me too > seriously... > > 1. Digital output pins on PICS are usually programmable as either inputs or > outputs, and they default to inputs. > > 2. Most digital IC's, regardless of what they do can sink more than they > can > source. So, an LED to ground might not be such a good idea as turning it > around > and running it from the positive rail, although the sense is reversed of > course. What you have described might be working, but the LED is lighting > so > weakly that you cannot see it - 10k is a bit big. A 'scope or good high > impedance DMM might be a better tool. > > 3. Check that your oscillator is actually oscillating, if you can. A scope > is > handy here, again. > > 4. So many people omit to do this: I know that C is preferable to assembly > language, but have a look at the assembler output from the compiler and > then > have a look to see if the instructions being emitted make sense. You might > find > that you're just writing to memory locations rather than doing any real > I/O, > for example. What you're trying to do here should only amount to a few > instructions, so check that these are correct. > > Just thoughts, but (4) is very worthwhile. It's a while since I played with > PICs, but they're a bit quirky and you have to go through the motions to > check > that you're not doing something daft. > > On Sunday 24 November 2013 12:07:13 Michael du Breuil wrote: > > I'm confident its user error, but I seem to be unable to program my > > PIC16F628A (it's my first foray into the world of PICs, been working with > > arm M4's). All I'm trying to do is turn on LED outputs, but I this > doesn't > > seem to be working. I'm trying to use the internal 4MHz oscillator, all > the > > port A and B pins (so everything except for VDD and VSS) are connected > to a > > 10K resistor and LED. This is all done on a breadboard, so it's possible > > there is an error in the wiring, but it appears to be correct. > > > > I'm using a PicKIT 2 to program it (and it can correctly auto identify > the > > device as a PIC16F628A) and believes it successfully flashes the device. > > This leads to me to believe I have a good chip, and the ICSP worked out > > correctly. > > > > I'm attempting to build with SDCC, with the appended code, but I don't > get > > any thing on any of the output pins, it simply sits there after power on. > > Are there any obvious errors here? > > > > Thanks for your time. > > > > > > > /////////////////////////////////////////////////////////////////////////// > > ////////// #include "pic16f628a.h" > > > > unsigned int __at 0x2007 __CONFIG = _INTOSC_OSC_NOCLKOUT & // > Internal > > oscillator > > _WDT_OFF & // No Watchdog > > _LVP_OFF & // No Low-Volt > > Program. > > _DATA_CP_OFF & // No Code > Protect > > _PWRTE_ON; > > > > static unsigned char count; > > > > void main(void) { > > CMCON |= 0x07; // Disable comparators. NEEDED FOR NORMAL PORTA > > TRISB = 0x00; // Set port B as all outputs > > TRISA = 0x00; // Set port A as all outputs > > PORTA = 0xFF; > > PORTB = 0xFF; > > > > while(1) {} > > } > > -- > Richard. > PGP Key-id: 0x5AB3D350 > > Be careful of reading health books, you might die of a misprint. > -- Mark Twain > > > ------------------------------------------------------------------------------ > Shape the Mobile Experience: Free Subscription > Software experts and developers: Be at the forefront of tech innovation. > Intel(R) Software Adrenaline delivers strategic insight and game-changing > conversations that shape the rapidly evolving mobile landscape. Sign up > now. > http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk > _______________________________________________ > Sdcc-user mailing list > Sdc...@li... > https://lists.sourceforge.net/lists/listinfo/sdcc-user > |