From 8a8ddeeeab97d61dc82b901e5201baf510caac97 Mon Sep 17 00:00:00 2001
From: aiminick <83101338@qq.com>
Date: Fri, 31 May 2019 21:57:12 +0800
Subject: [PATCH] Create ds3231-rtc.md

---
 docs/ds3231-rtc.md | 92 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 docs/ds3231-rtc.md

diff --git a/docs/ds3231-rtc.md b/docs/ds3231-rtc.md
new file mode 100644
index 0000000..4380987
--- /dev/null
+++ b/docs/ds3231-rtc.md
@@ -0,0 +1,92 @@
+# RTC Mod DS3231 Readme
+
+## 1. Change to root:
+
+```
+sudo -i
+```
+
+## 2. Disable Fake-Hwclock Service:
+
+```
+systemctl mask fake-hwclock.service
+```
+
+## 3. Copy boot kernel:
+
+```
+cd /boot/
+cp /boot/EFI/BOOT/bootaa64.efi  ./kernel8.img
+```
+
+## 4. Edit file: /boot/config.txt
+
+#### Change
+
+```
+...
+
+## RPI AARCH64 BOOT CORE CONF ##
+arm_64bit=1
+arm_control=0x200 
+armstub=RPI_EFI.fd 
+disable_commandline_tags=2 
+device_tree_address=0x8000 
+device_tree_end=0x10000 
+device_tree=bcm2710-rpi-3-b-plus.dtb
+hdmi_force_hotplug=1
+force_turbo=1
+initial_turbo=30
+disable_splash=1
+boot_delay=1
+dtparam=random=on
+##   Do not change above !!   ##
+
+...
+
+```
+
+#### To:
+
+```
+...
+
+## RPI AARCH64 BOOT CORE CONF ##
+arm_64bit=1
+arm_control=0x200
+#armstub=RPI_EFI.fd
+kernel=kernel8.img
+#disable_commandline_tags=2
+#device_tree_address=0x8000
+#device_tree_end=0x10000
+device_tree=bcm2710-rpi-3-b-plus.dtb
+force_turbo=1
+initial_turbo=30
+disable_splash=1
+boot_delay=1
+dtparam=random=on
+
+dtoverlay=i2c-rtc,ds3231
+
+##   Do not change above !!   ##
+
+...
+
+```
+
+## 5. Edit file: /boot/rc-local 
+
+Befor "exit 0", add context bellow:
+
+```
+
+# read rtc-time
+hwclock -r
+
+# write rtc-time to system
+hwclock -s
+
+exit 0
+```
+
+