Hezhou AIR105-nucleo development board with built-in DAPLink

# Nucleo-Like AIR105 Development Board
## Introduction:
The Shanghai Hezhou AIR105 development board is made with reference to the Nucleo version, based on the Cortex-M4F AIR105 (M*1903).

**Thanks very much to IOSetting for exploring AIR105 and the project templates it created, [link](https://gitee.com/iosetting/air105_project)**

The DAPLink communication interface is changed to Type-c, and it also comes with a USB Hub for connecting to the USB of AIR105, and an additional USB-A on the debugger side for connecting additional debugging peripherals (such as logic analyzers).

The (almost) standard Arduino interface is brought out, and all pins are brought out on the outer circle to facilitate the production of various types of expansion boards.

The onboard emulator is DAPLink, which supports CDC serial port. The chip uses AIR32F103CBT6. The firmware used can be downloaded from the attachment below: air32f103xb_full.hex, [reference project](https://oshwhub.com/s8gar88a/SWD-WHISPERER).

The board comes with a super capacitor to maintain the operation of the NTC. The JP10 shorting point needs to be changed. After the change, the reset button on the board will be **invalid**, please pay extra attention.
## PCB production/component purchase matters
The board is made using **KiCAD 7.0**, and there is no LCEDA free proofing, please pay attention. The attachment below provides the PCB source file nucleo-like-air105-PCB.7z.

The minimum line width, line spacing, and aperture of this PCB meet the Jiali Chuang 2-layer free board process, and the following Gerber proofing (nucleo-like-air105-gerber.zip) can be used directly.

All components are packaged in 0603 format, and all pin headers and female headers have a 2.54mm pitch. You can use the interactive BOM below (nucleo-like-air105-bom.html) to purchase components.

The schematic diagram can be seen in the following nucleo-like-air105-sch.pdf
## Functional description of short-circuit points on the board
AIR105 does not have JTAG function, SWD only, so the following nRST TDO TDI connection is invalid
| Label | Function | Default state |
| --- | --- | --- |
| JP3 | Onboard debugger Boot0 (for brick recovery) | Disconnected |
| JP4 | Debugger nRST output pin | Disconnected |
| JP5 | Debugger TDO pin | Disconnected |
| JP6 | Debugger TDI pin | Disconnected |
| JP7 | Debugger serial port RX | Connected |
| JP8 | Debugger serial port TX | Connected |
| JP9 | Debugger MCO (clock output) | Disconnected |
| JP10 | VBAT33 source selection | Connected to w/RESET |
| JP11 | PC3 for external ADC | Disconnected |
| JP12 | PC4 for external ADC | Disconnect|

## Other pin function descriptions on the board

| Label| Function| Default state|
| --- | --- | --- |
| JP1 | 5V source selection (external VIN step-down/provided by debugger) | Connect to debugger 5V |
| JP2 | MCU 3.3V total current measurement| Short|
| JP13 | UART0 of AIR105, used for downloading programs| Disconnect|
| J402 | Debugger signal lead-out|
| J403 | Debugger serial port signal output|
| J404 | Whether SWCLK/SWDIO is connected to the target| Connect|

## The hardware and PCB silk screens in the hardware welding
picture are slightly inconsistent, because VBUS Detect and some other silk screen details were changed later![IMG_1090.jpg] ![IMG_1092.jpg]
##
After the debugger is burned and soldered, you need to burn the debugger firmware. Download air32f103xb_full.hex below, use a 1.27MM burning needle, and use J401 to burn the firmware. The picture below is the corresponding pin diagram.
![IMG_108119111.jpg] Burn the following Hex file to 0x08000000 and you can use it.

This DAPlink firmware supports SWD, JTAG (not supported by AIR105), CDC serial port, SWO/ITM Trace (not supported by AIR105)

daplink_firmware.zip contains bl and if firmware, which can be downloaded separately if needed
## About VBATT33 power supply setting (untested)
This development board supports the selection of VBATT33 power source
JP10 short point can be reset by using the on-board reset button when it is in w/RESET state The chip
is in SuperCAP so that the RTC can still run after power failure (because there is a supercapacitor on the board)

## First power-on burning
The first time the new chip is powered on, the SWD burning may be automatically turned off. The simpler solution is to press reset and then quickly download it in Keil:)

## Project Example 1
Let's be lazy and use GPIO/Blink in [Project](https://gitee.com/iosetting/air105_project) of IOSetting, then open the project to compile, run and download.

We can see that the light will flash and the serial port will output content at the same time.