Re: newbie:Simple LED sequence?


"Bob Monsen" <rcsurname@xxxxxxxxxxx> wrote in message
news:pan.2005.09.20.22.58.43.448485@xxxxxxxxxxxxxx
> On Tue, 20 Sep 2005 17:15:02 +0000, Terry Pinnell wrote:
>
>> ehsjr <ehsjr@xxxxxxxxxxxxxxxx> wrote:
>>
>>
>>> It was another damn "use a PIC" post. Some of these posters drive
>>> me crazy. Never a "Wow John, you sure put a lot of work into that,
>>> nice job!" Never a complete project, with a schematic and source
>>> code. Just "you could use a PIC". Hell, if you did what those
>>> pic-ophiles do, your posts would say "use a soldering iron."
>>> One thing's for sure - we can't criticize the PIC designs posted as
>>> solutions to requests from posters. I'll tell you this, I'll put
>>> any one of the solutions you've offered in the newsgroup against
>>> all of the posted "PIC solutions", combined. Your solutions are
>>> always great. Theirs are non-existant.
>>>
>> Agreed. I could probably have made a movie of it in the time it would
>> take a PIC-er to just get started! Here it is:
>> http://www.terrypin.dial.pipex.com/Images/LED-Sequencer4MB.wmv
>
> This took 5 minutes to code (adapted another project). 15 if you include
> the setup, programming, testing, and bugfix (I inadvertently forgot to
> call init(), and it didn't work the first time). Only one chip, a pot, 5
> resistors, and 4 leds. Sadly, I don't have a movie camera, or I would
> record it. This is compiled with the free 'hitech lite' C compiler, and is
> downloaded to a pickit 1 using lawlor's usb_pickit for linux.
>
> The PIC12F675 is an 8 pin uC, which supports ADC, timer interrupts, and
> such. Pin 7 is used as the ADC input, so changing the voltage changes the
> rate of change of the display, from once every 2 seconds to as fast as it
> can go. The period is about Vin/Vcc * 2048 for Vin > 0.
>
> Pin 6, 5, 3, and 2 are A, B, C, and D. Pin 4 is the reset, pin 1 is Vcc,
> and pin 8 is GND. A-D can source up to 20mA, so a 1k resistor between it
> and the LED limits current to about 3.5mA.
>
> (for the curious, it uses a 1ms interrupt to do delays. The result of
> the high byte of the AD is between 0 and 255. Thus 8 * AD is from 0 to
> 2040, and just delaying that number of ms interrupts provides the ability
> to change the period from fast to slow)
>
> BTW, I'm sure we all appreciate JF's and Terry's efforts to help people
> out. I wish everybody's posted circuits were as well thought out, tested,
> and nicely presented as the ones they post.
>
> Regards
>
> ---------------------------------------------------------------------------
> #include <pic.h>
>
> __CONFIG(UNPROTECT & BORDIS & MCLREN & PWRTDIS & WDTDIS & INTIO);
>
> unsigned int g_ticks; /* Ticks since startup */
>
> #define TICKS_PER_SECOND 1000
>
> #define LED_A GPIO1
> #define LED_B GPIO2
> #define LED_C GPIO4
> #define LED_D GPIO5
>
> void init_gpio(void)
> {
> GPIO = 0;
> }
>
> void init_tmr0(void)
> {
> /* prescaler is 1:4, GPIO pullups are disabled */
> OPTION = 0x81;
> }
>
> void init_tmr1(void)
> {
> T1CON = 0; /* Disabled */
> }
>
> void init_comparator(void)
> {
> CMCON = 0x7; /* Turn off the comparator */
> VRCON = 0x0;
> }
>
> void init_a2d(void)
> {
> ANSEL = 0x11; /* Fosc/8 and RA0 is analog */
> ADCON0=0x00; // Left justify output
> ADON=1; // turn on the A2D conversion module
> }
>
> void init_ee()
> {
> }
>
> void init_interrupts(void)
> {
> INTCON = 0xA0;
> }
>
> void init(void)
> {
> OSCCAL = _READ_OSCCAL_DATA();
>
> TRISIO = 0x01; /* RA0 is ad input, rest are outputs */
>
> init_gpio();
> init_tmr0();
> init_tmr1();
> init_comparator();
> init_a2d();
> init_interrupts();
> }
>
> unsigned int get_voltage (void)
> {
> GODONE=1; /* initiate conversion */
>
> while(GODONE) /* wait for result */
> {
> continue;
> }
>
> return ADRESH;
> }
>
> void wait_ms(unsigned int x)
> {
> unsigned int temp = g_ticks + x;
> while (temp != g_ticks);
> }
>
> void main(void)
> {
> int state = 0;
>
> init();
>
> LED_A = 1;
> LED_B = 1;
> LED_C = 0;
> LED_D = 0;
>
> for (;;)
> {
> unsigned int ms_to_wait = get_voltage() * 8;
>
> wait_ms(ms_to_wait);
> switch(state)
> {
> case 0:
> LED_A = 0;
> LED_C = 1;
> state++;
> break;
>
> case 1:
> LED_B = 0;
> LED_D = 1;
> state++;
> break;
>
> case 2:
> LED_C = 0;
> LED_A = 1;
> state++;
> break;
>
> case 3:
> LED_D = 0;
> LED_B = 1;
> state = 0;
> break;
> }
> }
> }
>
> static void interrupt isr(void)
> {
> T0IF = 0;
> TMR0 = 6;
>
> g_ticks++;
> }
>
>

What program lang did you use It looks like C to me or is it Basic?

Eric


.

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