Bare metal libraries and projects for Allwinner F1C100s/F1C200s SOC

Libraries and tools

• f1c100s/arm926 - Various ARMv5-related headers

• f1c100s/drivers - Low-level peripheral drivers. Currently work-in-progress:

  • f1c100s_clock - Clock controller (CCU)
  • f1c100s_intc - Interrupt controller
  • f1c100s_gpio - GPIO, external interrupts
  • f1c100s_timer - Timers, watchdog
  • f1c100s_pwm - PWM outputs
  • f1c100s_uart - 16550-compatible UART
  • f1c100s_de - Display Engine (TCON, DEBE, DEFE)
  • f1c100s_tve - Undocumented TV(CVBS) encoder
  • f1c100s_tvd - Undocumented TV(CVBS) decoder

• lib - Miscellaneous non hardware-related libraries

• tools/mksunxi - A tool to add checksum to eGON.BT0 header. Taken from xboot project

Projects

All projects are targeted for Lichee Nano devboard with 800x480 LCD.

• hello_led - Yet another LED blinking project
• simple_loader - Very simple second-stage loader for booting bare metal apps from SPI flash
• lcd_test - Example of display driver usage with simple graphics library
• lvgl_demo - Demonstration project of LVGL library
• tv_out_test - Test project for TVE driver
• tv_in_test - Test project for TVD driver

Required tools

• Visual Studio Code with Cortex-Debug plugin
• arm-none-eabi-gcc

For debugging:

• Any OpenOCD-compatible JTAG adapter (I'm using FT2232)
• MicroSD to JTAG adapter board (pinout) (DIY adapter PCB project for DipTrace)
• OpenOCD

Building

Run make -C projects/<project_name>

Running

With U-Boot

• Copy <project_name>.bin file to SD card
• Run it with the following commands:

fatload mmc 0:1 80000000 <project_name>.bin
go 80000000

With simple_loader

• Compile simple_loader project
• Use mksunxi tool to fix eGON.BT0 header in simple_loader.bin
• Flash simple_loader.bin to SPI flash at offset 0, using U-Boot or FEL mode
• Compile your project with -DLOAD_HEADER option (enabled by default in all projects)
• Flash your code to SPI flash at offset 0x10000

Via JTAG

This will work only if there is no bootable code in the SPI Flash chip.

Set your JTAG adapter config file path in the OPENOCD_ADAPTER option of makefile, run make -C projects/<project_name> load

Debugging

You can debug your code using Cortex-Debug plugin

• Compile and write simple_loader to SPI flash, it will enable JTAG and perform DRAM initialization on start
• Set your JTAG adapter type in .vscode/launch.json config file
• Press F5 to start debug