adding initial eMMC pages

docs/helios64/emmc.md

@@ -0,0 +1,31 @@
+## eMMC
+
+Helios64 use the Samsung KLMAG1JETD-B041 chip, this storage has features:
+
+ - embedded MultiMediaCard Ver. 5.1 compatible.
+ - SAMSUNG eMMC supports features of eMMC5.1 which are defined in JEDEC Standard.
+ - Major Supported Features : HS400, Field Firmware Update, Cache, Command Queuing, Enhanced Strobe Mode, Secure Write Protection, Partition types.
+ - Non-supported Features : Large Sector Size (4KB).
+ - Backward compatibility with previous MultiMediaCard system specification (1bit data bus, multi-eMMC systems).
+ - Data bus width : 1bit (Default), 4bit and 8bit.
+ - MMC I/F Clock Frequency : 0 ~ 200MHz
+ - MMC I/F Boot Frequency : 0 ~ 52MHz
+
+SAMSUNG eMMC adopts Enhanced User Data Area as Single-Level Cell (SLC) Mode.
+Therefore when master adopts some portion as enhanced user data area in User Data Area, that area occupies double size of original set up size. (ex> if master set 1MB for enhanced mode, total 2MB user data area is needed to generate 1MB enhanced area).
+
+The eMMC chip installed in Helios64 support the HS400 MODE, with following features:
+
+ - eMMC 5.1 product supports high speed DDR interface timing mode up to 400MB/s at 200MHz with 1.8V I/O supply.
+ - HS400 mode supports the following features:
+ - DDR Data sampling method
+ - CLK frequency up to 200MHz DDR (up to 400Mbps)
+ - Only 8-bits bus width available
+ - Signaling levels of 1.8V
+ - Six selectable Drive Strength (refer to the table below)
+
+Following table describe the I/O Driver Strength Types
+
+![driver type](/helios64/img/emmc/driver-type.png)
+		
+Support of Driver Type-0 is default for HS200 & HS400 Device

mkdocs.yml

@@ -95,6 +95,7 @@ nav:
     - UEXT: 'helios64/uext.md'
     - UPS: 'helios64/ups.md'
     - USB: 'helios64/usb.md'
+    - eMMC: 'helios64/emmc.md'
   - Documents: 'helios64/docs.md'
   - Install: 'helios64/install.md'
 - Helios4: