I'm writing bare metal code(no os) on omap4460 (cortex a9), and i do not succeed to set up correctly gptimer1.
This is my code ( by following the OMAP4460 TRM)
/* for forwarding pending interrupts from distributor to Cpu interfaces */
*(volatile unsigned int *)(GICD_BASE + GICD_CTLR ) |= 0x00000001;
/* signaling interrupt by the cpu interface to the connected processor*/
*(volatile unsigned int *)(GICC_BASE + GICC_CTLR ) |= 0x00000001;
/* position the timer1 handler */
irq_table_function[GPT1_IRQ] = timer1handler;
/* clocks timer1 block */
*(volatile unsigned int *)CM_WKUP_CLKSTCTRL |= 0x00000003;
*(volatile unsigned int *)CM_WKUP_GPTIMER1_CLKCTRL |= 0x01000000;
*(volatile unsigned int *)CM_WKUP_GPTIMER1_CLKCTRL |= 0x00000002;
/* enable GPTimer1 functional and interface blocks */
*(volatile unsigned int *)GPT1MS_TIOCP_CFG |= 0x00000300;
/* capture interrupt enable */
*(volatile unsigned int *)GPT_TIER |= 0x00000004;
/* enable autoreload */
*(volatile unsigned int *)GPT_TCLR |= 0x00000002;
/* prescaler equal to zero */
*(volatile unsigned int *)GPT_TCLR &= ~0x0000003C;
/* positive increment value */
*(volatile unsigned int *)GPT_TPIR = 232000;
/* negative increment value */
*(volatile int *)GPT_TNIR = -768000;
/* load value */
*(volatile unsigned int *)GPT_TLDR = 0xFFFFFFE0;
/* enable timer1 */
*(volatile unsigned int *)GPT_TIER |= 0x00000001;
When i run the code, i never go to my interrupt vector table, my interrupt vector table is correctly set, since "svc 0" works.
I don't even see the timer counter running.
Please any idea, on what i'm missing? Rony.
i finally get the right initialization sequence, but forget to post back my code.
This is how i initialize gptimer1, hope it may help
/* clocks timer1 block */
*(volatile unsigned int *)CM_WKUP_CLKSTCTRL |= 0x00000003;
*(volatile unsigned int *)CM_WKUP_GPTIMER1_CLKCTRL &= ~0x01000000;
*(volatile unsigned int *)CM_WKUP_GPTIMER1_CLKCTRL |= 0x00000002;
/* enables for forwarding pending interrupts from distributor
to Cpu interfaces */
*(volatile unsigned int *)(GICD_BASE + GICD_CTLR ) |= 0x00000003;
/* set the priority of the interrupt */
*(volatile unsigned int *)(GICD_BASE + GICD_IPRIORITYR_IRQ37 ) |= 0x00000200;
/* set enable bit of IRQ37 */
*(volatile unsigned int *)(GICD_BASE + GICD_ISENABLER37) |= 0x00000002;
/* enables signaling interrupt by the cpu interface to the connected processor*/
*(volatile unsigned int *)(GICC_BASE + GICC_CTLR ) |= 0x00000003;
/* interrupt priority mask */
*(volatile unsigned int *)(GICC_BASE + GICC_PMR ) = 0x00000080;
/* forward the interrupt only to the processor which request the interrupt */
*(volatile unsigned int *)(GICD_BASE + GICD_SGIR) |= 0x02000000;
/* software reset */
*(volatile unsigned int *)GPT1MS_TIOCP_CFG |= 0x00000002;
/* RESET & Power settings*/
/* wait until reset release */
while( (*(volatile unsigned int *)GPT_TISTAT & 0x00000001) == 0)
waitingtime++;
/*GPT1MS_TIOCP_CFG [0]AUTOIDLE =0x0 : L4 clock free-running*/
*(volatile unsigned int *)GPT1MS_TIOCP_CFG &= ~(0x1 << 0);
/* idle mode equals to no-idle mode */
*(volatile unsigned int *)GPT1MS_TIOCP_CFG |= 0x00000008;
/*Functional clock is maintained during wake-up period */
*(volatile unsigned int *)GPT1MS_TIOCP_CFG |= 0x00000300;
/*NO Wake-up line assertion GPT1MS_TIOCP_CFG[2]ENAWAKEUP=0x0*/
*(volatile unsigned int *)GPT1MS_TIOCP_CFG &= ~(0x1 << 2) ;
/*GPT1MS_TIOCP_CFG [5]EMUFREE =0x1 : Timer counter free running in emulation*/
*(volatile unsigned int *)GPT1MS_TIOCP_CFG |= (0x1 << 5);
/* Enable wake-up interrupt events */
*(volatile unsigned int *)GPT_TWER |= 0x00000007;
/* Posted mode active */
*(volatile unsigned int *)GPT_TSICR |= 0x00000004;
/* enable autoreload */
*(volatile unsigned int *)GPT_TCLR |= 0x00000002;
/* set prescale clock timer value (PTV) to 1 */
/* set PREscaler =128
and thus FCLK=38.4 MHz / 128 = 300 KHz << OCPCLK=38.4 / 4 = 9.6 MHz */
*(volatile unsigned int *)GPT_TCLR |= 0x00000018;
/* enable prescaler */
*(volatile unsigned int *)GPT_TCLR |= 0x00000020;
/* Overflow interrupt enable */
*(volatile unsigned int *)GPT_TIER |= 0x00000007;
/* Load timer counter value */
*(volatile unsigned int *)GPT_TCRR = 0xFD000000;
/* load value */
*(volatile unsigned int *)GPT_TLDR = 0xFFE00000;
*(volatile unsigned int *)GPT_TPIR = 232000;
/* negative increment value */
*(volatile int *)GPT_TNIR = 0xFFF44800;
/* we position the timer1 handler */
irq_table_function[GPT1_IRQ] = timer1handler;
/* enable timer1 */
*(volatile unsigned int *)GPT_TCLR |= 0x00000001;
Best regards,
Rony