This repository contains information and mainline related sources of a CDR board based on AllWinner's A20(sun7i) SoC.
- SoC: AllWinner A20(sun7i) Dual-core Arm Cortex-A7
- RAM: 128MB 16bit@480MHz H5TQ1G63DFR-11C
- ROM: 8M SPI flash w25q64
- PMU: AXP209
- Accelerometer: lis3dh
(WIP)
Currently explored available peripherals:
- 1xlcd/lvds port (lcd0)
- 1xcsi port, with 1xi2c embedded (csi0, i2c1)
- 1xusb otg (usb0)
- 1xi2c (i2c2)
- 1xnand (nand0)
- 4xUART (uart0, uart1, uart3, uart7)
There is no actual schematic for this board found yet. However, there is a schematic for another CDR solution designed by AllWinner available at doc/A20-CDR-V0-2-20150312.pdf. Nevertheless that board shares many similarities with this one, some significant differences are already observed. Take that as a reference at your own risk.
(WIP)
There is a standard 40pin parallel RGB lcd port on board, connected to panel controller lcd0 on chip. For instructions about driving lcds, please refer to LCD.
There is a mini-HDMI port on board. HDMI support is enabled in both u-boot and kernel by default with configurations provided by this repository.
USB0 in A20 SoC features a dual-role controller thus can be operated in both host and peripheral mode. However, the mini-USB port on board attached to USB0 did not wire cd pin to the chip, so the otg functionality is not supported. You have to specify the role of USB0 manually in the device-tree file or switch it in procfs. All of the device-tree files in this repository set USB0 to peripheral mode by default.
With the USB gadget support in kernel, this board can be emulated as a variety of devices, which enables fast and convenient communication between this board and a PC. Guides on emulating this board as some devices via configfs are listed below:
- Board can be recognized as a net adapter and share network with PC
- (WIP)
- (WIP)
For more about configfs USB gadget, please refer to kernel documentation.
There is a lis3dh accelerometer from STMicroelectronics on board, connected to i2c1 bus at address 0x19. For detailed instructions, please refer to Accelerometer.
Compared with cheap USB cameras, DVP cameras are kinda obsolete these days thus they may never be tested on this board. This is just a reminder for someone who attempts to adapt a DVP camera for this board that, the IOs and AVDD for the camera are powered by LDO3 and LDO4 of axp209, the PMU on this board. The default output voltage of LDO3 and LDO4 is set to 3.3V to use PE port as general purpose IOs, but you have to set it to the proper level for your sensor in the device tree source.