PRU access to GPIO1_16 on AM335x

Enric Balletbo i Serra

Hi all,

I followed the PRU Getting Started Guide and the PRU Training Labs, With following code I'm able to toggle some GPO pins without problems. I'm wondering if I can access to other gpios that are not in GPO register, for example access to AM335x gpio1_16. Is that possible ? And if it's possible how can I toggle this pin ?

void main() {
	uint32_t gpio;

	/* Clear SYSCFG[STANDBY_INIT] to enable OCP master port */
	CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;

	/* GPI Mode 0, GPO Mode 0 */
	CT_CFG.GPCFG0 = 0;

	gpio = 0xFFFFFFFF;

	__R30 = 0x0;

	/* Toggle the LEDs */
	/* TODO: Create stop condition, else it will toggle indefinitely */
	while(1)
	{
		__R30 ^= gpio;

		__delay_cycles(10000);

	}
}

Thanks in advance,

Enric

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi Enric,

Yes, this is possible. You just have to pinmux the pin to GPIO function, then write to the GPIO bank registers: set direction of GPIO and set value. GPIO registers are described in section 25.4 of the AM335X TRM Rev. L.

0 Enric Balletbo i Serra over 10 years ago in reply to Biser Gatchev-XID

Intellectual 575 points

Hi Biser,
Thank you so much for your answer, are you able to provide a small example on how to do this? please.

Best regards,
Enric

0 Biser Gatchev-XID over 10 years ago in reply to Enric Balletbo i Serra

TI__Guru**** 393215 points

I'm not exactly a SW expert, however, let's take GPIO1_16 for example:

GPIO1_16 is pinmuxed on pin GPMC_A0. The pinmux register for this pin is CONF_GPMC_A0, located at address 0x44E0_F840. See section 9.3.1.49 from the TRM for register fields description. GPIO mode value is 7.

GPIO1 bank direction register is GPIO1_OE, located at address 0x4804_C134. See section 25.4.1.16 from the TRM for register fields description. To set GPIO1_16 as output you must write 0 in bit 16.

GPIO1 output register is GPIO1_DATAOUT, located at address 0x4804_C13C. See section 25.4.1.18 from the TRM for register fields description. To toggle GPIO1_16 you must write 0 (alternating with 1) in bit 16.

0 Enric Balletbo i Serra over 10 years ago in reply to Biser Gatchev-XID

Intellectual 575 points

Thank you so much.

Processors

Processors forum

PRU access to GPIO1_16 on AM335x