Upfate Hardware I2C page

docs/helios64/gpio.md

@@ -1,6 +1,6 @@
 Helios64 provides 16 GPIOs via a 20-Pin header (P5). Those GPIOs are provided via an 16-bit IO Expander [PCA9655E](http://www.onsemi.com/PowerSolutions/product.do?id=PCA9655E) connected to I2C bus 2.
 
-![GPIO](/helios64/img/gpio/gpio.jpg)
+![P5 Location](/helios64/img/gpio/gpio.jpg)
 
 ## Pinout
 

docs/helios64/i2c.md

@@ -1,39 +1,26 @@
-## I2C Overview
-
-Helios64 support I2C bus for the low-speed communication between devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interface and other similar peripherals in embedded systems.
-In order to communicate with each I2C slave device you will need an address and communication scenario.
-
-Please take caution of the reserved address when you use the I2C interface, below is the reseved address list:
-
-Slave Address |	R/W Bit |	Description
---------------|---------|-------------------
-000 0000 |	0  |	General call address
-000 0000 |	1  |	START byte(1)
-000 0001 |	X  |	CBUS address(2)
-000 0010 |	X  |	Reserved for different bus format (3)
-000 0011 |	X  |	Reserved for future purposes
-000 01XX |	X  |	Hs-mode master code
-111 10XX |	X  |	10-bit slave addressing
-111 11XX |	X  |	Reserved for future purposes
-
+Helios64 supports I2C bus for low-speed communication between devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals. In order to communicate with each I2C slave device you will need an address and communication scenario.
 
 ## I2C bus on Helios64 / RK3399
 
-The I2C controller on RK3399 support following features:
+The I2C controller on RK3399 supports following features:
 
 - 9 on-chip I2C controllers
 - Multi-master I2C operation
 - Support 7bits and 10bits address mode
 - Serial 8bits oriented and bidirectional data transfers can be made
 - Software programmable clock frequency
-- Data on the I2C-bus can be transferred at rates of up to 100 kbit/s in the Standardmode, up to 400 kbit/s in the Fast-mode or up to 1 Mbit/s in Fast-mode Plus.
+- Data on the I2C-bus can be transferred at rates of up to 100 kbit/s in the Standardmode, up to 400 kbit/s in the Fast-mode or up to 1 Mbit/s in Fast-mode Plus
 
 
-## Internal Bus (system reserved, NOT for user application)
+**Note:** In the implementation we divided the I2C controller into 2 categories:
 
-In the implementation, we divide the I2C controller into 2 category.
-The first implementation is for system (internal bus) and the other one is for user application (external).
-Below figure describe the I2C Map inside the board:
+* Internal Bus, reserved for the system
+* Externel Bus, allocated for user application
+
+## Internal Bus
+
+!!! Warning
+    Theses buses and addresses should not be accessed directly by user. Incorrect configuration can damage the board.
 
 Bus 0:
 
@@ -43,7 +30,6 @@ RK808-D | 0x1b     |            |
 SYR837  | 0x40     |            |
 SYR838  | 0x41     |            |
 
-
 Bus 2:
 
 Slave   | Address  | Description|
@@ -57,36 +43,46 @@ Slave   | Address  | Description|
 ------- | ------   |------      |
 FUSB302 | 0x22     |            |
 
-Above bus number and also including bus number 1,3,5 are reserved for system use, therefore not accessible to the user.
-
-!!! Warning
-    This bus number and address should not be accessed directly by user. Incorrect configuration can damaged the board!
+Above list also includes buses number 1,3,5 which are reserved for system use, therefore not accessible to the user.
 
 ## External Bus
 
-Helios64 exposed Bus number 7 and 8 of the I2C in **P2** and **P1** pinout, respectively.
-This I2C bus can be connected to the external devices.
+Helios64 exposes Bus number 7 and 8 respectively on **P2** and **P1** headers.
 
-As described on below figure of I2C (pin header number *3* and *4*), user can access the device at bus number 7.
-For the UEXT (pin header number *5* and *6*), user can access the device at bus number 8.
+All the I2C buses on the board are using voltage level of 3.3V. Note that Helios64 is integrated with level translator and pull up resistor.
 
-All the I2C bus in the board are using voltage level of 3.3V, please notice Helios64 is integrated with level translator and pull up resistor.
+Please take caution of the reserved address when you use the I2C interface, below is the reserved address list:
 
-### I2C at P1 Header
+Slave Address |	R/W Bit |	Description
+--------------|---------|-------------------
+000 0000 |	0  |	General call address
+000 0000 |	1  |	START byte(1)
+000 0001 |	X  |	CBUS address(2)
+000 0010 |	X  |	Reserved for different bus format (3)
+000 0011 |	X  |	Reserved for future purposes
+000 01XX |	X  |	Hs-mode master code
+111 10XX |	X  |	10-bit slave addressing
+111 11XX |	X  |	Reserved for future purposes
 
-Helios64 board exposes the SoC I2C Bus 1, on header **P1**. Below is the header pin-out.
+### I2C Header (P1)
 
-![I2C Pinout](/helios64/img/i2c/i2c_pinout.png)
+Helios64 board exposes I2C Bus 8 on header P1.
 
-This I2C device working with 3 pin bus (SDA, SCK, and GND), and also in band addressing.
-We can use a 7 bit addressing to distinguish every device, but some address is reserved for the internal communication of the Helios64 board.
+![P1 Location](/helios64/img/i2c/i2c.jpg)
 
-### I2C at UEXT
+This I2C device works with 3 pin bus (SDA, SCL, and GND), and also in band addressing. Below is the header pin-out:
 
-The I2C header bus also can be found at UEXT connector (can be found at **P2** header at the the board [overview](/helios64/hardware/overview) page) on the header number 5 and 6.
-Below is the detail description of the UEXT connector:
+![I2C Pinout](/helios64/img/i2c/i2c_pinout.jpg)
 
-![I2C at UEXT](/helios64/img/uext/UEXT_pinout.png)
+### UEXT Header (P2)
+
+The I2C Bus 7 can be found on the UEXT header (P2).
+
+![P2 Location](/helios64/img/i2c/uext.jpg)
+
+![I2C at UEXT](/helios64/img/i2c/uext_pinout.jpg)
+
+Below is the full pinout of the UEXT header:
 
 Pin No  | Description
 --------|-------------
@@ -103,22 +99,16 @@ Pin No  | Description
 
 ## Usage under Linux
 
-### External bus block device under linux
-
-Below table describe the external bus of I2C under Linux,
+Below table list the I2C external bus device name as detected under Linux:
 
 Bus number | Device Block | Description  |
 -----------|--------------|--------------|
  7         | /dev/i2c-7   |              |
  8         | /dev/i2c-8   |              |
 
-
 ### Checking the I2C Communication under linux
 
-In order to communicate with the I2C devices, first we need to identify the I2C bus.
-By performing scan you can see wether system detect the devices.
-
-We can follow this step to perform the scanning process:
+In order to communicate with the I2C devices, first we need to identify the I2C bus. By performing scan you can see whether the system can detect device.
 
 1. Install the Linux i2c tools.
 
@@ -142,9 +132,4 @@ root@helios64:~# i2cdetect -y 8
 70: -- -- -- -- -- -- -- --   
 ```
 
-Here we can see there is a device detected at the address 0x3c. If you have connected more than just one I2C device on the **P1** header, there will be more device with different address detected on the bus.
-
-
-### Application example
-
-We have demonstrated the use of I2C bus of our board in the OLED application, as shown in the [I2C(OLED)](/helios4/i2c/) page you can communicate to the external device by using the external I2C bus.
+Here we can see there is a device detected at the address 0x3c. If you have connected more than just one I2C device on the **P1** header, there will be more devices with different addresses detected on the bus.