long lastTime=0 ; long now=0; public void myFun() { now=System.currentTimeMillis(); if (now-lastTime>500) { //do something lastTime=now; } }
long lastTime=0 ; long now=0; public void myFun() { now=System.currentTimeMillis(); if (Math.abs(now-lasttime)>500) { //do something last=now; } }
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <string.h> #include <time.h> #include <errno.h> #include <termios.h> #define GPIO_ADDR 0x18040000 // base address #define GPIO_BLOCK 48 // memory block size char *portname = "/dev/ttyATH0"; volatile unsigned long *gpioAddress; int set_interface_attribs (int fd, int speed, int parity) { struct termios tty; memset (&tty, 0, sizeof tty); if (tcgetattr (fd, &tty) != 0) { printf("error %d from tcgetattr", errno); return -1; } cfsetospeed (&tty, speed); cfsetispeed (&tty, speed); tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8; // 8-bit chars // disable IGNBRK for mismatched speed tests; otherwise receive break // as \000 chars tty.c_iflag &= ~IGNBRK; // disable break processing tty.c_lflag = 0; // no signaling chars, no echo, // no canonical processing tty.c_oflag = 0; // no remapping, no delays tty.c_cc[VMIN] = 0; // read doesn't block tty.c_cc[VTIME] = 5; // 0.5 seconds read timeout tty.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl tty.c_cflag |= (CLOCAL | CREAD);// ignore modem controls, // enable reading tty.c_cflag &= ~(PARENB | PARODD); // shut off parity tty.c_cflag |= parity; tty.c_cflag &= ~CSTOPB; tty.c_cflag &= ~CRTSCTS; if (tcsetattr (fd, TCSANOW, &tty) != 0) { printf ("error %d from tcsetattr", errno); return -1; } return 0; } void set_blocking (int fd, int should_block) { struct termios tty; memset (&tty, 0, sizeof tty); if (tcgetattr (fd, &tty) != 0) { printf ("error %d from tggetattr", errno); return; } tty.c_cc[VMIN] = should_block ? 1 : 0; tty.c_cc[VTIME] = 5; // 0.5 seconds read timeout if (tcsetattr (fd, TCSANOW, &tty) != 0) printf ("error %d setting term attributes", errno); } int gpioRead(int gpio) { unsigned long value = *(gpioAddress + 1); //printf("value =%d\n",value); //printf("(1<<gpio) =%d",(1 << gpio)); return (value & (1 << gpio)); } // "1" (output) or "0" (input) void gpioDirection(int gpio, int direction) { unsigned long value = *(gpioAddress + 0); // obtain current settings if (direction == 1) { value |= (1 << gpio); // set bit to 1 } else { value &= ~(1 << gpio); // clear bit } *(gpioAddress + 0) = value; } void gpioSet(int gpio, int data) { unsigned long value = *(gpioAddress + 2); // obtain current settings if (data == 1) { value |= (1 << gpio); // set bit to 1 } else { value &= ~(1 << gpio); // clear bit } *(gpioAddress + 2) = value; } /*void gpioSet(int gpio, int value) { if (value == 0) { *(gpioAddress + 4) = (1 << gpio); } else { *(gpioAddress + 3) = (1 << gpio); } }*/ int gpioSetup() { int m_mfd; if ((m_mfd = open("/dev/mem", O_RDWR)) < 0) { return -1; } gpioAddress = (unsigned long*)mmap(NULL, GPIO_BLOCK, PROT_READ|PROT_WRITE, MAP_SHARED, m_mfd, GPIO_ADDR); close(m_mfd); if (gpioAddress == MAP_FAILED) { return -2; } return 0; } int main(int argc, char **argv) { int rs485_de=7; int rs485_re=13; gpioSetup(); gpioDirection(rs485_de,1);//set pin output gpioDirection(rs485_re,1);//set pin output int fd = open (portname, O_RDWR | O_NOCTTY | O_SYNC); if (fd < 0) { printf ("error %d opening %s: %s", errno, portname, strerror (errno)); return -1; } set_interface_attribs (fd, B115200, 0); // set speed to 115,200 bps, 8n1 (no parity) set_blocking (fd, 0); // set no blocking //get Model Name int cmd_len=7; char w_buff[8]; w_buff[0]=0x01; w_buff[1]=0x02; w_buff[2]=0x03; w_buff[3]=0x04; w_buff[4]=0x05; w_buff[5]=0x06; w_buff[6]=0x07; w_buff[7]='\0'; for (int t=0;t<20;t++) { gpioSet(rs485_de,1); //Set RS485 to Send Mode gpioSet(rs485_re,1); usleep (100); write (fd, w_buff, cmd_len); usleep (cmd_len*100); // sleep enough to transmit the command date gpioSet(rs485_de,0); // Set RS485 to Receive Mode gpioSet(rs485_re,0); usleep (10 * 1000); //wait a little time before read data char buf [100]; int n = read (fd, buf, sizeof buf); // read up to 100 characters if ready to read printf("rec:%d bytes\n",n); for (int i=0;i<n;i++) { printf("%d\t",buf[i]); } printf("\n"); } }
echo "27" > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio27/direction
echo "1" > /sys/class/gpio/gpio27/valueor
echo "0" > /sys/class/gpio/gpio27/value2. Direct Access GPIO Register，這種方式需要知道GPIO所對應的暫存器位置 ，適合以C語言開發，並對切換GPIO腳位速度有需求的使用者，例如RS 485應用。
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <string.h> #include <time.h> #define GPIO_ADDR 0x18040000 // base address #define GPIO_BLOCK 48 // memory block size volatile unsigned long *gpioAddress; //Read GPIO Status //return 0 -->Low //return >0 -->High int gpioRead(int gpio) { unsigned long value = *(gpioAddress + 1); return (value & (1 << gpio)); } // "1" (output) or "0" (input) void gpioDirection(int gpio, int direction) { // obtain current GPIO settings unsigned long value = *(gpioAddress + 0); if (direction == 1) { value |= (1 << gpio); // set bit to 1 (output) } else { value &= ~(1 << gpio); // clear bit (input) } *(gpioAddress + 0) = value; } //Set GPIO void gpioSet(int gpio, int data) { // obtain current GPIO settings unsigned long value = *(gpioAddress + 2); if (data == 1) { value |= (1 << gpio); // set bit to 1 (High) } else { value &= ~(1 << gpio); // clear bit (Low) } *(gpioAddress + 2) = value; } //Init GPIO Address, if /dev/mem not foud, you need to rebuild Image and add this module int gpioSetup() { int m_mfd; if ((m_mfd = open("/dev/mem", O_RDWR)) < 0) { return -1; } gpioAddress = (unsigned long*)mmap(NULL, GPIO_BLOCK, PROT_READ|PROT_WRITE, MAP_SHARED, m_mfd, GPIO_ADDR); close(m_mfd); if (gpioAddress == MAP_FAILED) { return -2; } return 0; } int main(int argc, char **argv) { int pin=27; int ms=500; gpioSetup(); sscanf(argv[1], "%d", &pin); gpioDirection(pin,1);//set pin output for (int i=0;i<100;i++) //blink system led { gpioSet(pin,1); //set syteme led high usleep(1000*ms); //sleep 500ms gpioSet(pin,0); //set system led low usleep(1000*ms); //sleep 500ms } }
esptool.py --port /dev/cu.wchusbserial1410 --baud 115200 write_flash --flash_size=detect 0 ~/Downloads/esp8266-20180511-v1.9.4.bin
pip3 install esptool
pip3 install adafruit-ampy
ls /dev/cu.*
esptool.py --port /dev/cu.wchusbserial1410 erase_flash
esptool.py --port /dev/cu.SLAB_USBtoUART --baud 460800 write_flash --flash_size=detect 0 ~/Downloads/esp8266-20180511-v1.9.4.bin
esptool.py --port /dev/cu.wchusbserial1410 --baud 115200 write_flash --flash_size=detect 0 ~/Downloads/esp8266-20180511-v1.9.4.bin
ampy --port /dev/cu.wchusbserial1410 ls
ampy --port /dev/cu.SLAB_USBtoUART ls
import time from machine import Pin led = Pin(2, Pin.OUT) led.value(1) while True: led.value(0) time.sleep_ms(500) led.value(1) time.sleep_ms(500)
ampy --port /dev/cu.SLAB_USBtoUART ls
ampy --port /dev/cu.wchusbserial1410 put main.py接下來按下RST鍵，藍色LED就會以0.5秒間隔閃爍。
EditText it is always enabled, regardless of the value of the attribute.true" or "false".@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final TextView textView=(TextView)findViewById(R.id.txt); Button button=(Button)findViewById(R.id.add); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int num=0; if (!textView.getText().toString().equals("")) { num=Integer.parseInt(textView.getText().toString()); } num++; textView.setText(String.valueOf(num)); } }); }
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.example.boywhychen.context_menu.MainActivity"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/txt" android:freezesText="true" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/add" android:text="Add" android:layout_below="@+id/txt" /> </RelativeLayout>
