Update Hardware SPI & UEXT page

docs/helios64/i2c.md

@@ -76,7 +76,7 @@ This I2C device works with 3 pin bus (SDA, SCL, and GND), and also in band addre
 
 ### UEXT Header (P2)
 
-The I2C Bus 7 can be found on the UEXT header (P2).
+The I2C Bus 7 can be found on the [UEXT header (P2)](/helios64/uext).
 
 ![P2 Location](/helios64/img/i2c/uext.jpg)
 

docs/helios64/spi.md

@@ -1,28 +1,20 @@
-!!! notice
+RK3399 has 6x SPI controllers with the following features:
-	***Preliminary Info***
-
-RK3399 has SPI controller with following features:
-
-- 6 on-chip SPI controllers
 
 - Support master and slave mode, software-configurable
-
 - DMA-based or interrupt-based operation
-
 - Embedded two 32x16bits FIFO for TX and RX operation respectively
 
-On Helios64 the bus are divided into three types: unused, system (internal bus) and user application (external)
+On Helios64, the buses are divided into three types: *Not Available*, *System* (internal bus) and *User* (external bus).
 
 | Bus | Usage |  Remarks |
 |-----|-------|-----------|
-| 0 | Not Used | |
+| 0 | Not Available | |
 | 1 | System | Bootable SPI Flash |
-| 2 | External | User Application |
+| 2 | User | User Application |
-| 3 | Not Used | |
+| 3 | Not Available | |
-| 4 | Not Used | |
+| 4 | Not Available | |
 | 5 | System | Reserved for Production use only |
 
-
 ## Internal Bus
 
 | Bus | Chip Select |  Device | Remarks |
@@ -30,7 +22,6 @@ On Helios64 the bus are divided into three types: unused, system (internal bus)
 |  1  | 0 | W25Q128JV | Bootable SPI Flash |
 |  5  | 0 | W25X20CL | SATA Controller ROM |
 
-
 ### Bootable SPI Flash
 
 Helios64 is equipped with [Winbond W25Q128JV 3V 128M-Bit Serial Flash Memory](https://www.winbond.com/hq/product/code-storage-flash-memory/serial-nor-flash/?__locale=en&partNo=W25Q128JV)
@@ -38,15 +29,14 @@ as a Bootable SPI NOR Flash.
 
 This flash contains
 
-- preloader & bootloader
+- Preloader & bootloader
 
 | Binaries | Offset | Remarks |
 |----------|--------|---------|
 | Preloader | 0x0040 | U-Boot TPL & SPL |
 | Bootloader | 0x4000 | U-Boot & ATF |
 
-- electronic nameplate data in Security Register
+- Electronic nameplate data in Security Register
-
 
 ## External Bus
 
@@ -54,7 +44,9 @@ This flash contains
 |-----|-------------|---------|
 |  2  | 0 | User Application |
 
-SPI Bus for user application is exposed on [UEXT Connector (P2)](/helios64/uext)
+SPI Bus for user application is exposed on [UEXT header (P2)](/helios64/uext)
+
+![P2 Location](/helios64/img/spi/uext.jpg)
 
 ![!UEXT](/helios64/img/spi/spi_on_uext.png)
 
@@ -65,19 +57,4 @@ SPI Bus for user application is exposed on [UEXT Connector (P2)](/helios64/uext)
 | 9 | SCK |
 | 10 | SSEL |
 
-The pin voltage level is 3.3V
+**Note:** The pin voltage level is 3.3V.
-
-
-## Usage in Linux
-
-### Enable SPIDEV in device tree
-
-To make SPI device accessible by user space application, we need to create a device tree node.
-After the node has been created, user application can access the device at
-
-`/dev/spidev5.0`
-
-!!! note
-	*To Be Updated*
-
-

docs/helios64/uext.md

@@ -1,27 +1,16 @@
-## UEXT overview
+Helios64 has one UEXT (Universal-Extension-Connector) header which exposes 3 serial communication interfaces into a single header:
-the development boards so customer can choose which feature he want to use.
 
-UEXT (Universal-Extension-Connector) is board to board connector which support 3 serial communication interface, such as I2C, SPI, RS232.
+* I2C
-The combination of theese feature is supported by every decent microcontroller, this will enable broad choice to connect modules.
+* SPI
-UEXT gives you freedom to choose module that you want to use.
+* RS232 (UART)
-
-!!! Notice
-        As UEXT have RS232 and the Rx and Tx signals should be crossed we can say that UEXT on the board is with HOST; UEXT on the module is with SLAVE/DEVICE layout.
 
+![P2 Location](/helios64/img/uext/uext.jpg)
 
 ## Pinout Table
-Helios64 provides UEXT on header P2 which following the UEXT standard, containing UEXT, SPI, and I2C connector.
-You can find the P2 header from the connector/interface list at [hardware overview](/helios64/hardware) page.
 
-Please find this location of UEXT header:
+![P2 Pinout](/helios64/img/uext/uext_pinout.jpg)
 
-![P2 Location](/helios64/img/uext/UEXT_zoom.jpg)
+Below is the full pinout of the UEXT header:
-
-The pinout of the above P2 header is decribed by following figures:
-
-![P2 Pinout](/helios64/img/uext/UEXT_pinout.png)
-
-Below is the detailed description of UEXT header pinout:
 
 | PIN | Port | Remarks |
 |-----|------|-------------|
@@ -37,25 +26,18 @@ Below is the detailed description of UEXT header pinout:
 |10 | SSEL (SPI) | |
 
 !!! Warning
-       Please note the UEXT connector at Helios64 board doesn't provide the plastic covering, so be carefull with the header polarity!
+    Be careful with the header polarity when connecting.
-Make sure your device is correctly oriented before connecting!
 
-## SPI and I2C
+## SPI & I2C
 
-The implementation of SPI and I2C in the UEXT connector is follow similar convention in the Helios64 board. Please refer to this page:
+Refer to the respective pages directly:
 
 - [SPI](/helios64/hardware/)
 - [I2C](/helios64/I2C/)
 
+## RS232 (UART)
 
-## Exception
+The UART bus exposed on the UEXT header is the same than the RK3399 SoC serial console exposed on the USB Type-C. There is no dedicated UART bus on the UEXT connector. The intention is to allow user to connect to SoC serial console by another way than the USB-to-Serial bridge.
 
-We have connected the UART bus from the RK3399 to the serial console in the USB-C, so there is no dedicated line of UART in the UEXT connector.
+!!! Important
-The UART bus in this UEXT header is the parallel ones with the serial console.
+    If you connect some modules which might require dedicated serial UART line to the SoC, this module will not operate properly.
-Therefore if you connect some module which might ***require dedicated serial UART line*** to the RK3399, this module ***will not function as expected***.
-
-!!! Notes
-       Please note also, that GPS modules in UEXT format also will not work due to similar reason.
-
-## References
-https://www.olimex.com/Products/Modules/UEXT/