# Overview Development board for the USB host capabilities of the CH554E microcontroller with an integrated USB-A female connector for connecting USB devices like keyboards, mice, printers, hubs, etc. and a USB-A male connector for providing a serial interface for analysis and debugging on the PC. - Firmware (Github): https://github.com/wagiminator/Development-Boards/tree/main/CH554E_HostDevBoard  # Hardware ## Schematic  ## CH554E 8-bit USB Host Microcontroller The CH554 is a low-cost, 8-bit enhanced E8051 core microcontroller compatible with the MCS51 instruction set. 79% of its instructions are single-byte single-cycle instructions, and the average instruction speed is 8 - 15 times faster than that of the standard MCS51. The special xRAM supports direct memory access (DMA), data fast copy command, and double DPTR pointers. The CH554 has a built-in USB 2.0 controller and USB transceiver, it supports USB-Host mode and USB-Device mode, USB Type-C master-slave detection, full-speed (12Mbps) and low-speed (1.5Mbps) traffic, data packets of up to 64 bytes, and DMA. It has a factory built-in bootloader so firmware can be uploaded directly via USB without the need for an additional programming device. Specifications | CH554E :-------------- | :------ Program ROM | 14 KB Bootloader | 2 KB Data Flash | 128 bytes iRAM | 256 bytes xRAM | 1024 bytes GPIO Pins | 4 + 2*USB ADC Channels | 4x 8-bit PWM Channels | 2x 8-bit Timer/Counter | 3 Touch Key Channels | 4 USB modes | Host/Device USB Type-C | yes Interfaces | 2x UART, SPI Intern. Clock | 24/16/12/6/3/0.75 MHz ## CH340N USB to Serial Converter IC Since the USB port of the CH554E is used for host functionality, the CH340N USB to serial converter takes care of the information transfer via USB to the PC. The CH554E provides this information via its UART interface. ## USB Connectors The USB-A female connector is used to connect USB devices such as keyboard, mouse, printer, hub, etc. to the USB host provided by the CH554E. This port must also be used to upload firmware to the microcontroller, which requires a USB-A male-to-male cable or suitable adapter. The USB-A connector on the board is used to plug into a USB port on your PC and provides serial information for analysis and debugging coming from the CH554E's UART port.  # Software ## Installing Drivers for the Bootloader On Linux you do not need to install a driver. However, by default Linux will not expose enough permission to upload your code with the USB bootloader. In order to fix this, open a terminal and run the following commands: ``` echo 'SUBSYSTEM=="usb", ATTR{idVendor}=="4348", ATTR{idProduct}=="55e0", MODE="666"' | sudo tee /etc/udev/rules.d/99-ch55x.rules sudo service udev restart ``` On Windows you will need the [Zadig tool](https://zadig.akeo.ie/) to install the correct driver. Click "Options" and "List All Devices" to select the USB module, then install the libusb-win32 driver. ## Entering Bootloader Mode A brand new chip starts automatically in bootloader mode as soon as it is connected to the PC via USB. Once firmware has been uploaded, the bootloader must be started manually for new uploads. To do this, the board must first be disconnected from the USB port and all voltage sources. Now press the BOOT button and keep it pressed while reconnecting the board to the USB port of your PC. The chip now starts again in bootloader mode, the BOOT button can be released and new firmware can be uploaded within the next couple of seconds. ## Installing Toolchain for CH55x If you do not want to use the Arduino IDE, you can install the [CH55x Software Development Kit for the SDCC compiler](https://github.com/Blinkinlabs/ch554_sdcc). Follow the instructions on the website. In order for some programming tools to work, Python3 must be installed on your system. To do this, follow these [instructions](https://www.pythontutorial.net/getting-started/install-python/). In addition [pyusb](https://github.com/pyusb/pyusb) must be installed. On Linux (Debian-based), all of this can be done with the following commands: ``` sudo apt install sdcc python3 python3-pip sudo pip install pyusb ``` ## Preparing Arduino IDE - [Install ch55xduino](https://github.com/DeqingSun/ch55xduino). - Open the Arduino IDE. - Go to "Tools" -> "Board" -> "CH55x Boards" and select your chip. - Go to "Tools" and set the desired board options. - Go to "File" -> "Examples" -> "Examples for CH55x Board" and select a Sketch of your choice. - If your board is never used with ch55xduino before, you need to make the ch55x chip enter the bootloader mode. Hold the BOOT button pressed while connecting the board to the USB port of your PC. You do not need to do this if you have installed a blank new chip on the board. - Now you can upload your sketch. # References, Links and Notes - [EasyEDA Design Files](https://oshwlab.com/wagiminator) - [CH55x SDK for SDCC](https://github.com/Blinkinlabs/ch554_sdcc) - [ch55xduino](https://github.com/DeqingSun/ch55xduino) - [CH554 Datasheet](http://www.wch-ic.com/downloads/CH554DS1_PDF.html)    # License  This work is licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License. (http://creativecommons.org/licenses/by-sa/3.0/)