本文转载自：https://bbs.aw-ol.com/topic/3281/
由于UART0 被设定为系统dubug 输出（简单来说就是将ttyS0 设定为console），所以使用UART3 作为普通的串口，进行与别的设备通信。
1. 查看硬件电路图SCH_Schematic1_2022-11-23，查看uart3 的TX RX pin 脚 电路图pdf路径：Yuzukilizard/Hardware/Schematic/SCH_Schematic1_2022-11-23.pdf
从图中可以看出TX = PE12 RX = PE13 。
PE12 PE13 可以通过排插用杜邦线接出，排插电路图如下：
2. 由于pin脚复用原因，我们需要查看pin 脚复用情况
pin 脚复用手册V851SE_PINOUT_V0.1.xlsx路径： Yuzukilizard/Hardware/Datasheets/V851SE_PINOUT_V0.1.xlsx
记住PE12 PE13 用作UART3-TX UART3-RX 是function7 ，这个很重要，一会我们在board.dts 文件中需要用到。
3. 配置设备树文件 board.dts 设备树文件通过of 文件解析出属性，进一步被应用（原理此处不再介绍）。
board.dts 路径：tina-v853-docker/device/config/chips/v851s/configs/lizard/board.dts
在设备树中搜索UART 找到UART3 相关配置
代码语言：javascript复制&uart0 {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&uart0_pins_active>;
pinctrl-1 = <&uart0_pins_sleep>;
status = "okay";
};
&uart1 {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&uart1_pins_active>;
pinctrl-1 = <&uart1_pins_sleep>;
status = "disabled";
};
&uart2 {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&uart2_pins_active>;
pinctrl-1 = <&uart2_pins_sleep>;
status = "disabled";
};
&uart3 {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&uart3_pins_active>;
pinctrl-1 = <&uart3_pins_sleep>;
status = "okay";
};
&pio {
uart0_pins_active: uart0@0 {
allwinner,pins = "PH9", "PH10";
allwinner,function = "uart0";
allwinner,muxsel = <5>;
allwinner,drive = <1>;
allwinner,pull = <1>;
};
uart0_pins_sleep: uart0@1 {
allwinner,pins = "PH9", "PH10";
allwinner,function = "gpio_in";
allwinner,muxsel = <0>;
};
uart1_pins_active: uart1@0 {
allwinner,pins = "PG6", "PG7";
allwinner,function = "uart1";
allwinner,muxsel = <4>;
allwinner,drive = <1>;
allwinner,pull = <1>;
};
uart1_pins_sleep: uart1@1 {
allwinner,pins = "PG6", "PG7";
allwinner,function = "gpio_in";
allwinner,muxsel = <0>;
};
uart2_pins_active: uart2@0 {
allwinner,pins = "PA8", "PA9";
allwinner,function = "uart2";
allwinner,muxsel = <6>;
allwinner,drive = <1>;
allwinner,pull = <1>;
};
uart2_pins_sleep: uart2@1 {
allwinner,pins = "PA8", "PA9";
allwinner,function = "gpio_in";
allwinner,muxsel = <0>;
};
uart3_pins_active: uart3@0 {
allwinner,pins = "PE12", "PE13";
allwinner,function = "uart3";
allwinner,muxsel = <7>;
allwinner,drive = <1>;
allwinner,pull = <1>;
};
uart3_pins_sleep: uart3@1 {
allwinner,pins = "PE12", "PE13";
allwinner,function = "gpio_in";
allwinner,muxsel = <0>;
};1）将uart3 设定为 status = “okay”; 2）将uart3 pin 脚设为 allwinner,pins = “PE12”, “PE13”; 3）将uart3 pin复用为function7 ：allwinner,muxsel = <7>;
修改完成后，重新编译img
代码语言：javascript复制make -j1 V=s
pack使用烧录软件：PhoenixSuit ，具体烧录方法参考：https://dongshanpi.com/YuzukiHD-Lizard/03-1_FlashSystem/#usb
烧录后,通过adb shell 进入终端，就可以查看到设备节点：/dev/ttyS3 ,通过open 设备终端，就可以进行read write 操作。
4. 通过设备节点 /dev/ttyS3 进行收发操作
1）写应用程序
代码语言：javascript复制#include <stdio.h> /*标准输入输出定义*/
#include <stdlib.h> /*标准函数库定义*/
#include <unistd.h> /*Unix标准函数定义*/
#include <sys/types.h>
#include <sys/stat.h> /*六文件控制定义*/
#include <fcntl.h> /*PX终端控制定义*/
#include <termios.h>
#include <errno.h>
#include <string.h>
enum parameter_type {
PT_PROGRAM_NAME = 0,
PT_DEV_NAME,
PT_CYCLE,
PT_NUM
};
#define DBG(string, args...)
do {
printf("%s, %s()%u---",__FILE__,__FUNCTION__,__LINE__);
printf(string, ##args);
printf("n");
} while (0)
void usage(void) {
printf("You should input as: n");
printf("t select_test [/dev/name] [Cyclee Cnt]n");
}
int OpenDev(char *name) {
int fd = open(name, O_RDWR );
if (-1 == fd)
DBG("Can not OPen(%s)!", name);
return fd;
}
/*
* @brief 设置串口通信速率
* @param fd 类型 int打开串口的文件句柄长
* @param speed 类型 int 串口速度
* @return void
*/
void set_speed(int fd, int speed) {
int i;
int status;
struct termios Opt = {0};
int speed_arr[] = {B230400, B115200, B57600, B38400, B19200, B9600, B4800, B2400, B1200, B300, B38400, B19200, B9600, B4800, B2400, B1200, B300, };
int name_arr[] = {230400,115200, 57600, 38400, 19200, 9600, 4800, 2400, 1200, 300, 38400, 19200, 9600, 4800, 2400, 1200, 300, };
tcgetattr(fd, &Opt);
for ( i= 0; i < sizeof(speed_arr) / sizeof(int); i ) {
if (speed == name_arr[i])
break;
}
tcflush(fd, TCIOFLUSH);
cfsetispeed(&Opt, speed_arr[i]);
cfsetospeed(&Opt, speed_arr[i]);
Opt.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /*Input*/
Opt.c_oflag &= ~OPOST; /*Output*/
status = tcsetattr(fd, TCSANOW, &Opt);
if (status != 0) {
DBG("tcsetattr fd");
return;
}
tcflush(fd, TCIOFLUSH);
}
/**
*@brief 设置串口数据位，停止位和效验位
*@param fd 类型 int 打开的串口文件句柄
*@param databits 类 型 int 数 据位 取值 为 7 或者8
*@param stopbits 类 型 int 停 止位 取值为 1 或者2
*@param parity 类型 int 效验类型 取值为N,E,O,,S
*/
int set_Parity(int fd,int databits,int stopbits,int parity) {
struct termios options;
if ( tcgetattr( fd,&options) != 0) {
perror("SetupSerial 1");
return -1;
}
options.c_cflag &= ~CSIZE;
switch (databits) /*设置数据位数*/
{
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
fprintf(stderr,"Unsupported data sizen");
return -1;
}
switch (parity)
{
case 'n':
case 'N':
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case 'o':
case 'O':
options.c_cflag |= (PARODD | PARENB); /* 设置为奇效验*/
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'e':
case 'E':
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD; /* */
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'S':
case 's': /*as no parity*/
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;break;
default:
fprintf(stderr,"Unsupported parityn");
return -1;
}
/* 设置停止位*/
switch (stopbits)
{
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
fprintf(stderr,"Unsupported stop bitsn");
return -1;
}
/* Set input parity option */
if (parity != 'n')
options.c_iflag |= INPCK;
tcflush(fd,TCIFLUSH);
options.c_cc[VTIME] = 150; /* 15 seconds*/
options.c_cc[VMIN] = 0; /* Update the options and do it NOW */
if (tcsetattr(fd,TCSANOW,&options) != 0) {
perror("SetupSerial 3");
return -1;
}
return 0;
}
void str_print(char *buf, int len) {
int i;
for (i=0; i<len; i ) {
if (i == 0)
printf("n");
printf("0xx ", buf[i]);
}
printf("n");
}
int main(int argc, char **argv)
{
int i = 0;
int fd = 0;
int cnt = 0;
char buf[256];
char buf_s[4];
int ret;
fd_set rd_fdset;
struct timeval dly_tm; // delay time in select()
if (argc != PT_NUM) {
usage();
return -1;
}
sscanf(argv[PT_CYCLE], "%d", &cnt);
if (cnt == 0)
cnt = 0xFFFF;
fd = OpenDev(argv[PT_DEV_NAME]);
if (fd < 0)
return -1;
set_speed(fd,19200);
if (set_Parity(fd,8,1,'N') == -1) {
printf("Set Parity Errorn");
exit (0);
}
printf("Select(%s), Cnt %d. n", argv[PT_DEV_NAME], cnt);
while (i<cnt) {
FD_ZERO(&rd_fdset);
FD_SET(fd, &rd_fdset);
dly_tm.tv_sec = 5;
dly_tm.tv_usec = 0;
memset(buf, 0, 256);
ret = select(fd 1, &rd_fdset, NULL, NULL, &dly_tm);
DBG("select() return %d, fd = %d", ret, fd);
if (ret == 0)
continue;
if (ret < 0) {
printf("select(%s) return %d. [%d]: %s n", argv[PT_DEV_NAME], ret, errno,
strerror(errno));
continue;
}
i ;
ret = read(fd, buf, 256);
printf("Cnt%d: read(%s) return %d.n", i, argv[PT_DEV_NAME], ret);
str_print(buf, ret);
buf_s[0] = 0x55;
buf_s[1] = 0xAA;
buf_s[2] = 0x55;
buf_s[3] = 0xAA;
write(fd, buf_s, 256);
DBG("send over %dn");
}
close(fd);
return 0;
}2） 编写makefile
代码语言：javascript复制#CROSS_COMPILE = arm-linux-
#CROSS_COMPILE = arm-linux-gnueabihf-
CROSS_COMPILE=/home/xxx/v851s/Yuzukilizard/toolchain/gcc-linaro-5.3.1-2016.05-x86_64_arm-linux-gnueabi/bin/arm-linux-gnueabi-
# CPU = cortex-a7
# FPU = fpv4-sp-d16
AS = $(CROSS_COMPILE)as
LD = $(CROSS_COMPILE)ld
CC = $(CROSS_COMPILE)gcc
CXX = $(CROSS_COMPILE)g
CPP = $(CC) -E
AR = $(CROSS_COMPILE)ar
NM = $(CROSS_COMPILE)nm
STRIP = $(CROSS_COMPILE)strip
OBJCOPY = $(CROSS_COMPILE)objcopy
OBJDUMP = $(CROSS_COMPILE)objdump
RANLIB = $(CROSS_COMPILE)ranlib
SIZE = $(CROSS_COMPILE)size
TOP_DIR = $(shell pwd)
CFLAGS_inc_path = -I$(TOP_DIR)
EXE = UARTTest
# CFLAGS_inc_path = -I$(TOP_DIR)external/jpeg-9a
# for H.264 hardware codec
#CFLAGS_inc_path = -I$(TOP_DIR)/../../prebuilt/include/cedar
# CFLAGS = -std=gnu99 -mthumb -mabi=aapcs-linux -mlittle-endian
# CFLAGS = -fdata-sections -ffunction-sections
# CFLAGS = -mcpu=$(CPU) -mtune=$(CPU) -mfpu=$(FPU) -mfloat-abi=hard
SRC_HAL = ./
LIB_SRC := $(foreach spath, $(SRC_HAL), $(wildcard $(spath)*.c))
OBJECT = $(patsubst %.c,%.o,$(LIB_SRC))
LOCAL_INCLUDE = -I./
#CFLAGS = -O2 -ggdb3 -DNDEBUG
CFLAGS = $(LOCAL_INCLUDE) -static
# LDFLAGS = -L../../library/arm-linux-gnueabihf
# LIBS = -lawh264 -lvdecoder -lcdc_base -lMemAdapter -lVE -lvencoder -lvideoengine
all:$(EXE)
$(EXE):$(OBJECT)
@$(CC) $(OBJECT) -o $(EXE) $(CFLAGS)
# @echo -- gcc $(SRCS) --
@echo "Compile target done."
@echo "use src files"
$(OBJECT):
.PHONY:clean
clean:
@rm -rf *.o $(OBJECT) $(EXE)
@echo "Clean done." 需注意，将makefile 中的编译工具路径修改为自己的工具路径。
3） make 后，产生可执行文件，adb push 到开发板中进行执行，执行命令：
代码语言：javascript复制./UARTTest /dev/ttyS3 44）用杜邦线将PE12 PE13 GND 三根线接到电脑串口（需要串口转换小板子），波特率目前设定19200 ，使用串口工具，向板子随便发送数据，板子接受到数据，就会发送数据到电脑。
