AIO-3288J Buy Spec

Uses RK3288 Quad-Core Cortex-A17 CPU, up to 1.8Ghz , integrated Quad-Core Mali-T764 GPU. Onboard 4G LTE interface, multiple display interface and serial port. Support Android/Linux/Ubuntu system. It can be quickly applied to a variety of industries.

UART

Update time:2018-04-13 Views:1483

1 Intro

AIO-3288J  support SPI bridge / expansion of four enhanced functions of the serial  port (UART), respectively UART2, RS232 (上), RS485, UART3 and three  master comes with serial ports, respectively, UART1, RS232(下) Debug serial port. Each UART has a 256-byte FIFO buffer for data reception and transmission. among them:

  • UART1 ~ UART3 are TTL level interface, RS232 is RS232 level interface, RS485 is RS485 level interface

  • Each sub-channel UART baud rate, word length, parity format can be set independently, up to 2Mbps communication rate

  • Each sub-channel  has a receive / send independent 256 BYTE FIFO, FIFO interrupt can be  programmed according to user needs Trigger point

  • With sub-serial port receive FIFO timeout interrupt

  • Support for start bit error detection

AIO-3288J development board serial interface interface as follows:

TIM图片20180102164205.png

2 Configuration Steps

The spi to uart node have already been created in file kernel/arch/arm/boot/dts/firefly-rk3288-AIO.dts, Enable this node to use it:

 &spi0 {
     status = "okay";
     max-freq = <48000000>;     
     spidev@00 {
         status = "disabled";
         compatible = "linux,spidev";
         reg = <0x00>;
         spi-max-frequency = <48000000>;
     };
     spi_wk2xxx: spi_wk2xxx@00{
         status = "okay";
         compatible = "firefly,spi-wk2xxx";
         reg = <0x00>;
         spi-max-frequency = <10000000>;
         reset-gpio = <&gpio0 GPIO_C2 GPIO_ACTIVE_HIGH>;
         irq-gpio = <&gpio0 GPIO_A7 IRQ_TYPE_EDGE_FALLING>;
         cs-gpio = <&gpio5 GPIO_B5 GPIO_ACTIVE_HIGH>;
         pwr-en-gpio = <&gpio3 GPIO_B6 GPIO_ACTIVE_HIGH>;
     };
 };

2 Debug method

Configure the serial port, the hardware interface corresponding to the software node are:

RS485:/dev/ttysWK3
RS232(上):/dev/ttysWK1
RS232(下):/dev/ttyS3
UART1:/dev/ttyS1
UART2:/dev/ttysWK0
UART3:/dev/ttysWK2

The user can use  different host according to different interface USB to serial port  adapter to send and receive data to the serial port of the development  board, for example, the debugging steps of RS485 are as follows:

(1) Hardware connection.

Connect the A,  B, GND pins of the development board RS485 to the A, B, GND pins of the  host serial port adapter (USB to 485 serial port module) respectively.

(2) Open the host's serial terminal.

Run kermit on the terminal and set the baud rate:

$ sudo kermit
C-Kermit> set line /dev/ttyUSB0
C-Kermit> set speed 9600
C-Kermit> set flow-control none
C-Kermit> connect
  • /dev/ttyUSB0 is a device file for USB to serial adapter

  • baud is the "current-speed" attribute in the DTS node.

(3) Transmit data.

The device file for RS485 is /dev/ttysWK3. Run the following command in device:

echo firefly RS485 test... > /dev/ttysWK3

The serial terminal in the host PC will receive string "firefly RS485 test...".

(4) Receive data.

First, run the following command in device:

cat /dev/ttysWK3

Then input string "Firefly RS485 test..." in the serial terminal. You can see the same string received in the device.