ntpserver stats, 3

content/content/blog/timeserver.md

@@ -12,6 +12,81 @@ It has been joined the NTP pool, the statistics are available [here](https://www
 
 Some additional statistics graphs for the server are available [here](https://pv-stats.hottis.de/ntpserver).
 
+
+## Preparation of the BeagleBone
+
+The GPS module is connected via serial line to the UART of the BB.
+
+The additional connection of the PPS output with the PPS device of the Linux running on the BB via a GPIO must be prepared. A device tree overlay must be created and compiled:
+
+```
+/dts-v1/;
+/plugin/;
+
+/{
+    compatible = "ti,beaglebone", "ti,beaglebone-black";
+    part_number = "WN-PPS";
+    version = "00A0";
+
+    exclusive-use =
+        "P8.7",
+        "gpio2_2";
+
+    fragment@0 {
+        target = <&am33xx_pinmux>;
+        __overlay__ {
+            bs_pinmode_P8_7_0x27: pinmux_bs_pinmode_P8_7_0x27 {
+                pinctrl-single,pins = <0x090 0x27>;
+            };
+        };
+    };
+
+    fragment@1 {
+        target = <&ocp>;
+        __overlay__ {
+            bs_pinmode_P8_7_0x27_pinmux {
+                compatible = "pps-gpio";
+                status = "okay";
+                pinctrl-names = "default";
+                pinctrl-0 = <&bs_pinmode_P8_7_0x27>;
+                gpios = <&gpio2 2 0>;
+                assert-rising-edge;
+            };
+        };
+    };
+};
+```
+
+This file shall be compiled using
+
+```
+dtc -O dtb -o WN-PPS-00A0.dtbo -b 0 -@ WN-PPS-00A0.dts
+```
+
+The binary dtbo file then copied into `/lib/firmware` and mentioned in the `/boot/uEnv.txt`:
+
+```
+uboot_overlay_addr0=/lib/firmware/WN-PPS-00A0.dtbo
+```
+
+After a reboot the device file `/dev/pps0` should be available and using `ppstest /dev/pps0` you can test the connection:
+
+```
+root@david:/boot# ppstest /dev/pps0
+trying PPS source "/dev/pps0"
+found PPS source "/dev/pps0"
+ok, found 1 source(s), now start fetching data...
+source 0 - assert 1739442756.999984966, sequence: 306598 - clear  0.000000000, sequence: 0
+source 0 - assert 1739442757.999978472, sequence: 306599 - clear  0.000000000, sequence: 0
+source 0 - assert 1739442758.999976057, sequence: 306600 - clear  0.000000000, sequence: 0
+^C
+root@david:/boot# 
+```
+
+
+## Configuration of the ntpsec daemon
+
+
 ```
 interface listen all
 logconfig +all