doc: check and fix urls

use 'make linkcheck' to check urls

Signed-off-by: Jingru Wang <jingru@synopsys.com>

Author: wangnuannuan

doc/documents/contribute/CONTRIBUTING.rst

@@ -47,7 +47,7 @@ What should I know before I get started?
 Code of Conduct
 ===============
 
-This project adheres to the Contributor Covenant `code of conduct <./CODE_OF_CONDUCT.md>`_.
+This project adheres to the Contributor Covenant :ref:`code of conduct <code_guidelines>`.
 By participating, you are expected to uphold this code.
 Please report unacceptable behavior to `info@embarc.org <mailto:info@embarc.org>`_.
 
@@ -160,7 +160,7 @@ Enhancement suggestions are tracked as `GitHub issues <https://guides.github.com
 * **List some other text software platform where this enhancement exists.**
 * **Specify the name and version of the OS you're using.**
 
-`Template For Submitting Enhancement Suggestions <./ISSUE_TEMPLATE.md>`_
+:ref:`Template For Submitting Enhancement Suggestions <issue_guidelines>`
 ------------------------------------------------------------------------
 
 Your First Code Contribution

doc/documents/example/example.rst

@@ -72,6 +72,5 @@ The following application notes provide step-by-step instructions on a broad ran
 * `How to create your own peripheral modules for use with the ARC EMSK and embARC <https://foss-for-synopsys-dwc-arc-processors.github.io/pdf/20151013_embARC_application_note_create_module_EMSK_embARC_v3.pdf>`_
 * `Timer and ISR <https://foss-for-synopsys-dwc-arc-processors.github.io/pdf/20150805_embARC_application_note_timer_and_isr.pdf>`_
 * `Using a secondary bootloader on the EMSK <https://foss-for-synopsys-dwc-arc-processors.github.io/pdf/20150710_embARC_application_note_secondary_bootloader.pdf>`_
-* `Using a smart home IoT application with EMSK <https://foss-for-synopsys-dwc-arc-processors.github.io/pdf/embARC_appnote_how_to_use_smart_home_iot.pdf>`_
 
 .. note:: Confirm that the version of embARC OSP and board is the correct one as noted in the application note documents

doc/documents/getting_started/peripheral_preparation.rst

@@ -74,7 +74,7 @@ Other PMOD or Compatible Modules
 `Pmod AD2 <https://reference.digilentinc.com/reference/pmod/pmodad2/start>`_ : ADC type is AD7991, use **I2C** for data collection.
 Driver code at ``embarc_osp/device/peripheral/adc/ad7991``.
 
-`ESP01\/ESP01S <https://wiki.ai-thinker.com/esp8266/docs>`_ : Primary IC type is ESP8266, use **UART** interface for data changing and controlling.
+`ESP01\/ESP01S <https://www.espressif.com/en/support/documents/technical-documents>`_ : Primary IC type is ESP8266, use **UART** interface for data changing and controlling.
 Driver code at ``embarc_osp/device/peripheral/wifi/slip_esp``.
 
-The ESP01/ESP01S module is not originally a PMOD module, however it is PMOD compatible, meaning that you can wire it to PMOD interface on board. You need to connect GND(embARC) to GND(ESP) , 3.3V(embARC) to VCC(ESP), RXD(embARC) to TXD(ESP), and TXD(embARC) to RXD(ESP), respectively. Please take reference from datasheet of `ESP01\/ESP01S <https://wiki.ai-thinker.com/esp8266/docs>`_ and UART (type 4A) part of `Digilent Pmod Spec <https://www.digilentinc.com/Pmods/Digilent-Pmod_%20Interface_Specification.pdf>`_ for pin layout. 
+The ESP01/ESP01S module is not originally a PMOD module, however it is PMOD compatible, meaning that you can wire it to PMOD interface on board. You need to connect GND(embARC) to GND(ESP) , 3.3V(embARC) to VCC(ESP), RXD(embARC) to TXD(ESP), and TXD(embARC) to RXD(ESP), respectively. Please take reference from datasheet of `ESP01\/ESP01S <https://www.espressif.com/en/support/documents/technical-documents>`_ and UART (type 4A) part of `Digilent Pmod Spec <https://www.digilentinc.com/Pmods/Digilent-Pmod_%20Interface_Specification.pdf>`_ for pin layout. 

doc/documents/license/license.rst

@@ -79,7 +79,7 @@ AWS IoT Device C SDK
 ********************
 
 :Project homepage: https://github.com/aws/aws-iot-device-sdk-embedded-C
-:Project licensing: https://github.com/aws/aws-iot-device-sdk-embedded-C/blob/master/LICENSE.txt
+:Project licensing: https://github.com/aws/aws-iot-device-sdk-embedded-C/blob/master/LICENSE
 :LICENSE: `Apache License`_
 
 Doxygen
@@ -227,8 +227,8 @@ MRF24WG0MA PMOD WiFi
 NT-Shell
 ********
 
-:Project homepage: https://www.cubeatsystems.com/ntshell/
-:Project licensing: | https://www.cubeatsystems.com/ntshell/license.html
+:Project homepage: https://cubeatsystems.com/ntshell/
+:Project licensing: | https://cubeatsystems.com/ntshell/license.html
 			| The license
 			| • vtparse, vtparse_table are in the public domain.
 			| • ntshell, ntopt, ntlibc, text_editor, text_history are in the MIT license.