Hello,
I want to generate a PWM signal for two leds on my at91rm9200 board. But I need some helping information to get it to work.
void init_LEDs(void) { AT91C_BASE_PIOC->PIO_OER = AT91C_PIO_PC0 | AT91C_PIO_PC1; AT91C_BASE_PIOC->PIO_PER = AT91C_PIO_PC0 | AT91C_PIO_PC1; pullupdisable->PIOD_PPUDR = AT91C_PIO_PC0 | AT91C_PIO_PC1; AT91C_BASE_PIOC->PIO_CODR = AT91C_PIO_PC1 | AT91C_PIO_PC0; }
void timer2 (void) { unsigned int temp; init_LEDs(); AT91F_PIO_CfgPeriph(AT91C_BASE_PIOA,0, AT91C_PA17_TIOA0); // Base Adress PIO Controller A / / TIOAO Peripheral am PIO Controller A PA17 AT91F_PIO_CfgPeriph (AT91C_BASE_PIOA, 0, AT91C_PA18_TIOB0); // 0 = PIO Pin soll auf Peripherie B geschaltet werden www.mikrocontroller.net/.../70120 //config AIC AT91F_AIC_ConfigureIt(AT91C_BASE_AIC, AT91C_ID_TC0, AT91C_AIC_PRIOR_HIGHEST - 6, AT91C_AIC_SRCTYPE_EXT_POSITIVE_EDGE, (void (*) ())TC0_interrupt); // Base Adress AIC / Base Adress Timer0 / Priorität / Flanke-trigger / Handler AT91F_AIC_EnableIt( AT91C_BASE_AIC, AT91C_ID_TC0); // Base Adress AIC / Base Adress Timer0 --> enalbe interrupts for Timer0! //config PMC AT91F_PMC_EnablePeriphClock (AT91C_BASE_PMC,1 << AT91C_ID_TC0); // Base Adress PMC / Base Adress Timer0 --> wird mit Clock versorgt //Timer0 init //disable interrupts AT91C_BASE_TC0->TC_IER = 0; AT91C_BASE_TC0->TC_IDR = 0xF; // clear status bit temp = AT91C_BASE_TC0->TC_SR; temp = temp; // to get no warning ("temp" was set but never used) //TC_CMR Register AT91C_BASE_TC0->TC_CMR = 0x4 // use TimerClock5 | 0x0 << 1 // CLKI (Counter is incremented on rising edge of the clock) | 0x0 << 2 // BURST (clock is not gated by an external signal) | 0x0 << 3 // CPCSTOP (counter is not stopped when counter reaches RC) | 0x0 << 4 // CPCDIS (counter is not disabled when counter reaches RC) | AT91C_TC_EEVTEDG_NONE // EEVTEDG (none) | AT91C_TC_EEVT_RISING // EEVT (XC0 as output) | 0x0 << 7 // ENETRG (external event has no effect on the counter and the clock) // the external event only controls the TIOA output | AT91C_TC_WAVESEL_UPDOWN // WAVESEL | AT91C_TC_WAVE // WAVE (waveform is enabled) | AT91C_TC_ACPA_SET // ACPA (compare effect on TIOA) | AT91C_TC_AEEVT_NONE // AEEVT (external event effect on TIOA) | AT91C_TC_ASWTRG_NONE // ASWTRG (software trigger on TIOA) | AT91C_TC_BCPB_SET // BCPB (set - compare effect on TIOB) | AT91C_TC_BCPC_CLEAR // BCPC | AT91C_TC_BEEVT_NONE // BEEVT | AT91C_TC_BSWTRG_SET; // BSWTRG AT91C_BASE_TC0->TC_RA = 900; AT91C_BASE_TC0->TC_RB = 500; AT91C_BASE_TC0->TC_RC = 1000; AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; temp = AT91C_BASE_TC0->TC_SR; while(1); }
That's the whole code. I don't know how I can say that the PWM should be installed at LED1 and LED2 (PCO and PC1).
Moreover is there another notation for 0x0 << 1 (TC_CMR)? And I found nothing about the values I should use for TC_RA, TC_RB and TC_RC, in the datasheet.
best regards Bernd
"is there another notation for 0x0 << 1 "
Well, that's the standard 'C' shift operator - so any 'C' textbook should be able to answer that one!
Think about it: does shifting zero by any number of bits ever make any difference...?
no not really... that's right...
Could anybody explain to me how I have to install the PWM that I can see the two leds on PC1 and PC0 - getting on and off (slowly)
The PWM controllers normally comes pre-installed by the chip manufacturers ;)
yes - my English is not always as good as from a English man... but could you give me some advice for my problem?
Bernd
You might want to cross post your query to AT91.com, where they specialize in AT91 based chips. You might get a better answer there, although it usually takes a while to get a response.
English isn't my native language either, so I regularly manages to produce some interesting constructs :)
"You might want to cross post your query to AT91.com"
But be sure to include cross-references between your two threads!