Copyright (c) 2021 Xemex N.V.

All of the files in this folder were based on the
one from the Nordic nrf9160dk_nrf9160 board example.
The copyright and license of those files was:

Copyright (c) 2021 Nordic Semiconductor ASA
SPDX-License-Identifier: Apache-2.0

Secure vs Non-Secure
--------------------

The final firmware has two applications:
	- the SPM application
	- the Xemex application

The SPM is responsible for setting the peripherals, flash and RAM used by the Xemex application as non-secure.

For this reason, there are two board DTS configurations:
 - the secure one, dng_nrf9160, used by the SPM application
 - the non-secure one, dng_nrf9160ns, used by the Xemex application

Used Pins
---------
Name            Pin       Type             Configuration             Extra info               Use
Power low       P0.05     INPUT            NO PULL up no PULL DOWN   low is power LOW
V_cap enable    P0.07     OUTPUT                                     HIGH is ENABLED
TXD2            P0.08     OUTPUT UART                                                         UART MODBUS 
EN_RS_TX        P0.09     OUTPUT                                                              TX ENABLE MODBUS
EN_RS_RX        P0.10     OUTPUT                                                              RX ENABLE MODBUS
RXD2            P0.12     INPUT UART                                                          UART MODBUS 
LED1            P0.13     OUTPUT                                     HIGH is ACTIVE
LED2            P0.15     OUTPUT                                     HIGH is ACTIVE
SWI1            P0.16     INPUT             NO PULL up no PULL DOWN  BUTTON LOW is ACTIVE
TXD0            P0.18     OUTPUT UART                                                         UART TIFF           
RXD0            P0.19     INPUT UART                                                          UART TIFF
TXD3            P0.20     OUTPUT UART                                                         UART OPTO        
RXD3            P0.21     INPUT UART                                                          UART OPTO
FL_SI           P0.22     SPI OUTPUT DATA                                                     FLASH
FL_SCK          P0.23     SPI OUTPUT CLK                                                      FLASH
FL_SO           P0.24     SPI INPUT DATA                                                      FLASH
FL_CS           P0.25     SPI OUTPUT SELECT                                                   FLASH
SW_EXTERNAL     P0.26     OUTPUT                                      HIGH is ACTIVE          ANTENNA
SW_INTERNAL     P0.27     OUTPUT                                      HIGH is ACTIVE          ANTENNA
