# A device tree for my LORA HAT..
* Brings a UART out for talking to the HAT
* Leaves pins `7`, `13` and `15` free since these are used to control and monitor the HAT
* Has the SPI interface in case I add a screen, and an I2C interface for talking to peripherals.

Nb: screen is https://www.waveshare.com/wiki/3.5inch_RPi_LCD_(A)
```
               MangoPI MQ Pro GPIO header (dtb name: MangoPi MQ Pro)

Gpio Header:
                        func   des  pin       pin  des   func                       
                               3v3   1 --o o-- 2   5v                               
      i2c0 (2502000.i2c:205)  PG13   3 --o o-- 4   5v                               
      i2c0 (2502000.i2c:204)  PG12   5 --o o-- 6   gnd                              
                   free (39)   PB7   7 --o o-- 8   PB8   uart0 (2500000.serial:40)  
                               gnd   9 --o o-- 10  PB9   uart0 (2500000.serial:41)  
                  free (117)  PD21  11 --o o-- 12  PB5   free (37)                  
                  free (118)  PD22  13 --o o-- 14  gnd                              
                   free (32)   PB0  15 --o o-- 16  PB1   free (33)                  
                               3v3  17 --o o-- 18  PD14  spi1 (4026000.spi:110)     
      spi1 (4026000.spi:108)  PD12  19 --o o-- 20  gnd                              
      spi1 (4026000.spi:109)  PD13  21 --o o-- 22  PC1   free (65)                  
      spi1 (4026000.spi:107)  PD11  23 --o o-- 24  PD10  spi1 (4026000.spi:106)     
                               gnd  25 --o o-- 26  PD15  spi1 (4026000.spi:111)     
                  free (145)  PE17  27 --o o-- 28  PE16  free (144)                 
                   free (42)  PB10  29 --o o-- 30  gnd                              
                   free (43)  PB11  31 --o o-- 32  PC0   free (64)                  
                   free (44)  PB12  33 --o o-- 34  gnd                              
                   free (38)   PB6  35 --o o-- 36  PB2   uart4 (2501000.serial:34)  
                  free (113)  PD17  37 --o o-- 38  PB3   uart4 (2501000.serial:35)  
                               gnd  39 --o o-- 40  PB4   free (36)                  

Other gpio outputs of interest:
-- PD18: Blue Status Led - gpio (2000000.pinctrl:114)

Notes:
- I2C pins 3,5,27 and 28 (PG13, PG12, PE17 and PE16) have 10K pullup resistors to 3v3
- The Status LED (PD18) is common with the LED_PWM pin on the DSI/LVDS output
```