ZED Mini Carrier: GPIO for PPS

Hardware ZED Box
1

Hi guys,

I have been trying to learn the device tree of zedbox_mini_364. It seems that you have enabled a pps device as

pps {
			gpios = <0xf3 0x06 0x00>;
			compatible = "pps-gpio";
			status = "okay";
		};

which says that the 1PPS signal can be applied at the GPIO associated with the phandle 0xf3.

In below, I also found

gpio@2200000 {
			compatible = "nvidia,tegra234-gpio";
			reg-names = "security\0gpio";
			reg = <0x00 0x2200000 0x00 0x10000 0x00 0x2210000 0x00 0x10000>;
			interrupts = <0x00 0x120 0x04 0x00 0x121 0x04 0x00 0x122 0x04 0x00 0x123 0x04 0x00 0x124 0x04 0x00 0x125 0x04 0x00 0x126 0x04 0x00 0x127 0x04 0x00 0x128 0x04 0x00 0x129 0x04 0x00 0x12a 0x04 0x00 0x12b 0x04 0x00 0x12c 0x04 0x00 0x12d 0x04 0x00 0x12e 0x04 0x00 0x12f 0x04 0x00 0x130 0x04 0x00 0x131 0x04 0x00 0x132 0x04 0x00 0x133 0x04 0x00 0x134 0x04 0x00 0x135 0x04 0x00 0x136 0x04 0x00 0x137 0x04 0x00 0x138 0x04 0x00 0x139 0x04 0x00 0x13a 0x04 0x00 0x13b 0x04 0x00 0x13c 0x04 0x00 0x13d 0x04 0x00 0x13e 0x04 0x00 0x13f 0x04 0x00 0x140 0x04 0x00 0x141 0x04 0x00 0x142 0x04 0x00 0x143 0x04 0x00 0x144 0x04 0x00 0x145 0x04 0x00 0x146 0x04 0x00 0x147 0x04 0x00 0x148 0x04 0x00 0x149 0x04 0x00 0x14a 0x04 0x00 0x14b 0x04 0x00 0x14c 0x04 0x00 0x14d 0x04 0x00 0x14e 0x04 0x00 0x14f 0x04>;
			#interrupt-cells = <0x02>;
			interrupt-controller;
			#gpio-cells = <0x02>;
			gpio-controller;
			gpio-ranges = <0x02 0x00 0x00 0xa4>;
			phandle = <0xf3>;
		};

Can you help me indicate if the GPIO_11 according to your datasheet can be used to receive the PPS signal.

If not, I think it is highly necessary that you provide a guideline how to re-map GPIO_11 or GPIO_12 to receive the PPS signal.

Thanks.

2

Hi Walter @Myzhar,

Can you give me a hand with this?

Many thanks!

3

Hi,

I haven’t personally tested to use PPS but you can change gpios = <0xf3 0x06 0x00>; for gpios = <0xf3 0x69 0x00>; and this should enable PPS on GPIO12, you can verify the configuration by running sudo gpioinfo | grep "pps"

4

Hi Aldric @Aldric ,

many thanks for the help!

I took a lazy workaround and compiled the dtb directly on the device. After replacing the dtb in /boot/dtb and rebooting, I got

line 85: "PN.01"   input consumer="bus@0:pps"

I also notice that the pps was previously configured as

line 6: "PA.06" input consumer="bus@0:pps"

I think the remapping has worked but do not know if it is correct. Can you check?

It would also be wonderful if you could tell me which pin of the original 40-pin header matches pin 11 of the Zed Carrier Mini so that I can remap this pin for pwm.

Thanks!

5

GPIO 11 on the zedbox mini correspond to PQ.06 and pin 31 on Jetson Orin Nano devkit 40-pin header

6

And the PN.01 is the GPIO 12, correct? :smiley: Then I can close this issue. Thanks!