How to convert Quanzhi a40i/t3 to can through SPI

Full ambition A40i perhaps T3 Of CPU No middle CAN controller , But in the actual use process , use CAN, Usually SPI turn CAN The way .

This paper is based on Feiling embedded OKA40i-C Operate on the development board , Other brand development boards can be referred to as appropriate .

stay OKA40i-C On the base plate , All the way SPI, But because of the voltage and mcp2515 The voltage of does not match , Therefore, the serial port will be used 2 This group of multiplexes is SPI external mcp2515 modular .

according to CPU Chapter 3 of the manual describes , Can be PI17-19 Reuse as SPI1, use PH08 As an interruption .

A40i/T3 use sys_config.fex perhaps dts Configure pin multiplexing function , Let's use dts To configure .

01- open SPI1

modify sys_config.fex, take uart2 Configuration removed , open SPI1 Configuration of .

At the same time PH08 Comment out ：

At the same time, modify the device tree ：

02- modify defconfig

It is verified by other platforms , And adapt to the driver of the device tree mcp251x.c,

modify defconfig The configuration file ：

Networking support ---> CAN bus subsystem support --->CAN Device Drivers --->Microchip MCP251x SPI CAN controllers Choose .

At the same time, select SPI To configure , Supported by default , Not here .

03- To configure iproute

file system ：

buildroot-201611/configs/sun8iw11p1_hf_defconfig

It needs to be configured BR2_PACKAGE_IPROUTE2=y.

recompile , And package the image , burn .

04- test can0 node

After starting ,ifconfig Check to see if can0 node . Use the following command to test ：

ifconfig can0 down
ip link set can0 up type can bitrate 125000 triple-sampling on
ifconfig can0 up
cansend can0 123#12345678
candump can0

If necessary, please contact Feiling technical service personnel , Provide patch file .

matters needing attention

In the device tree , When used as an interrupt , because A40i/T3 Only use PH The pins of the group are multiplexed into interrupts , When setting an interrupt in the device tree, the following ：

interrupt-parent = <&pio>;
interrupts = <8 0>;

in addition , Pay attention to the interrupt trigger mode in the driver .