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很惭愧，就做了一点微小的工作

Dash

autossh multiple connection?

Dec 5, 2013
Technology

Strangely, I cannot enable the multiple SSH connections on OpenWRT.
The configuration file is listed as:

	config autossh
		option ssh	'-N -T -R 4381:localhost:22 root@XXX.xxx.xxx.xxx '
		option gatetime	'0'
		option monitorport	'20000'
		option poll	'600'
	#config autossh
	#	option ssh	'-L -N -T 10.0.0.1:9009:1XX.XX.XX.XXX:8000 xxx@xxx.xxx.xxx.xxx '
	#	option gatetime	'0'
	#	option monitorport	'20001'
	#	option poll	'600'

But only 1 connection could be enabled.
I doubt this is because of the startup scripts for /etc/init.d/autossh. I should change its methods.

	start() {
		config_load 'autossh'
		config_foreach start_instance 'autossh'
	}

But how to read and display the configuration files? It seems the multiple selections is hard to config…..

Configure samba server on Ubuntu

Dec 2, 2013
Technology

###Installation Update repository and install samba and samba services.

	$ sudo apt-get update
	$ sudo apt-get install samba smbfs

###Configuration Add a new samba user:

	Trusty@joggler:~$ sudo smbpasswd -a Trusty
	[sudo] password for Trusty: 
	New SMB password:
	Retype new SMB password:

Editing the /etc/samba/smb.conf:


	[samba]
	   comment = samba for ethernet users
	   path = /media/samba
	   valid users = Trusty
	   public = no
	   writable = yes
	   printable = no
	   create mask = 0765

	[homes]
	   comment = Home Directories
	   browseable = no

	security = user
	username map = /etc/samba/smbusers

Adding the mapping of the system user to samba user:

	Trusty@joggler:/media$ cat /etc/samba/smbusers 
	Trusty="Trusty"

Restarting the samba service and now you can login with your new username and password. ###Configure easy swat for samba, its description is listed as:
swat - Samba Web Administration Tool

	$ sudo apt-get install swat xinetd

edit the configuration files:

	Trusty@joggler:/etc/samba$ cat /etc/xinetd.d/swat 
	# description: SWAT is the Samba Web Admin Tool. Use swat \
	#              to configure your Samba server. To use SWAT, \
	#              connect to port 901 with your favorite web browser.
	service swat
	{
	        port    = 901
	        socket_type     = stream
	        wait    = no
	        user    = root
	        server  = /usr/sbin/swat
	        log_on_failure  += USERID
	        disable = no
	}

After restart xinetd, we can access http://YourIP:901 for configuration. ###Mount the samba partition We can add this line to the ~/.bashrc, then use mountsamba we could mount the samba disk to our own mounting point.

	alias mountsamba='sudo mount -t cifs //10.0.0.11/samba1/ -o user=Trusty,password=Trustywill,workgroup=WORKGROUP /media/samba'

On Windows it’s very convinient to mount the shared samba, but on Linux, only root could write to the samba disk , why?
###NFS Installation:

	$ sudo apt-get install nfs-kernel-server
	$ sudo apt-get install rpcbind

Configuration of the nfs server:

	Trusty@joggler:~$ cat /etc/exports 
	/home/Trusty 10.0.0.221(rw,sync,no_subtree_check) 10.0.0.11(rw,sync,no_subtree_check)
Restart the service of nfs:
	$ sudo service nfs-kernel-server restart
In client machine, Just add following lines to your /etc/fstab
	10.0.0.11:/home/Trusty   /media/nfs   nfs4   rsize=8192,wsize=8192,timeo=14,intr,_netdev	0 0

Restart and now in your own /media/nfs you will see the destination nfs directory.

GPIO Advanced in STM32

Dec 1, 2013
Technology

直接操作寄存器的好处，最主要的就是看中它的快。缺点在于比较晦涩，因为你需要了解到实现的底层。在官方库中，我们可以找到如下的定义：

//./Libraries/CMSIS/CM3/DeviceSupport/ST/STM32F10x/stm32f10x.h:
#define PERIPH_BASE           ((uint32_t)0x40000000) /*!< Peripheral base address in the alias region */
//./Libraries/CMSIS/CM3/DeviceSupport/ST/STM32F10x/stm32f10x.h:
#define APB2PERIPH_BASE       (PERIPH_BASE + 0x10000)
//./Libraries/CMSIS/CM3/DeviceSupport/ST/STM32F10x/stm32f10x.h:
#define GPIOA_BASE            (APB2PERIPH_BASE + 0x0800)
//./Libraries/CMSIS/CM3/DeviceSupport/ST/STM32F10x/stm32f10x.h:
#define GPIOA               ((GPIO_TypeDef *) GPIOA_BASE)
// Definition of the GPIO Types
/** 
  * @brief General Purpose I/O
  */

typedef struct
{
  __IO uint32_t CRL;
  __IO uint32_t CRH;
  __IO uint32_t IDR;
  __IO uint32_t ODR;
  __IO uint32_t BSRR;
  __IO uint32_t BRR;
  __IO uint32_t LCKR;
} GPIO_TypeDef;

/**
 * IO definitions
 *
 * define access restrictions to peripheral registers
 */

#ifdef __cplusplus
  #define     __I     volatile                /*!< defines 'read only' permissions      */
#else
  #define     __I     volatile const          /*!< defines 'read only' permissions      */
#endif
#define     __O     volatile                  /*!< defines 'write only' permissions     */
#define     __IO    volatile                  /*!< defines 'read / write' permissions   */
;

从上面就可以基本看出GPIO的相关知识。在GPIO的使用中我们需要注意7个寄存器：
CRL, CRH, IDR, ODR, BSRR, BRR, LCKR.
使用起来很简单，直接调用相应的寄存器操作就好：
GPIOA->CRL=0x00;
寄存器的定义在手册中有详细的介绍。简单的说，CRL和CRH被称之为Configuration Register， 配置寄存器，而IDR和ODR则是数据寄存器，一个是INPUT一个是OUTPUT。 置位/复位寄存器BSRR，还有一个16位的复位寄存器BRR， 还有一个32位的锁定寄存器LCKR，设置好对应的寄存器则可执行相应的操作。

输入和输出操作可以直接操作寄存器，例如点亮和熄灭LED都是可以直接用操作寄存器来完成。而对键盘的操作，则是读入值。

	#define GET_LEFT()	(!(GPIOD->IDR&GPIO_Pin_3))

能使用库函数的场合，除非对IO要求非常高，否则不建议直接操作寄存器。因为出错误的概率会远远增大。

STM32 and 25F080

Dec 1, 2013
Technology

SST25F080,高达 1M 字节的串行 FLASH 存储器,此芯片为-50 版,即 SPI 速度可达到 50M,利用 STM32 的最高速 SPI 接口(36M),读写速度绝对不比并行 FLASH 慢.
连线图如下：

25f080.jpg

RTC on STM32

Nov 30, 2013
Technology

RTC(Real Time Clock) 在STM32中可以理解为内置的一个部件，和传说中的DS1302是有差别的。尽管官方发布的程序可以将RTC搞成一个万年历。
###配置RTC RTC需要顺带使用后备寄存器， 因为RTC是一个简单的秒中断定时器，关于年日月分秒的信息需要在掉电保存时依然放在某个地方，这个地方就是STM32的后备寄存器。配置好以后，尽管系统关电，依靠板子上的后备电池，依然可以保存32768的晶振和后备寄存器的数据。
配置RTC的方法：

	#include "stm32f10x_bkp.h"
	#include "stm32f10x_pwr.h"
	#include "stm32f10x_rtc.h"
	//使能一些外设
		RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);
		PWR_BackupAccessCmd(ENABLE);

###判断RTC是否被配置过 下面的函数被用于判断RTC是否被配置过：

/**************************************************************
** 函数名:TestRtc
** 功能:测试RTC用
** 注意事项:用于显示RTC是否已经设置过.
***************************************************************/
void TestRtc(void)
{
	if(RTC_Blank)
	{
		USART1_Puts("The Time is not set\r\n");
	}
	else
	{
		USART1_Puts("Time Setted.\r\n");
	}
}

这个函数判断RTC_Blank全局变量的值，而全局变量的值则在配置RTC的时候被设定。

void RTC_Configuration(void)
{
  //......
	if(BKP_ReadBackupRegister(BKP_DR1) != 0xA5A5)
		{
	//......
			RTC_Blank=1;	//这个标志代表RTC是没有预设的(或者说是没有上纽扣电池)
	
		}

如果RTC后备寄存器的值为设定为0xA5A5，则代表RTC已经被设置过。否则，我们认为它处于未被设置过的状态。
###使用RTC的秒中断 在NVIC中，需要有下列的定义，以标识RTC的秒中断。

	/* RTC */
	NVIC_InitStructure.NVIC_IRQChannel = RTC_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_Init(&NVIC_InitStructure);

对应的中断响应例程则定义在stm32f10x_it.c中：

/*******************************************************************************
* Function Name  : RTC_IRQHandler    RTC中断
* Description    : 
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
extern volatile bool Sec;	//1S标志
void RTC_IRQHandler(void)
{
	if(RTC_GetITStatus(RTC_IT_SEC) != RESET) //RTC发生了秒中断（也有可能是溢出或者闹钟中断)
	{
		RTC_ClearITPendingBit(RTC_IT_SEC);
		Sec=TRUE;
		
		//以免RTC计数溢出,这里限制了RTC计数值的大小.0x0001517f实际就是一天的秒数
		if(RTC_GetCounter() >= 0x0001517f)	
		{
			RTC_SetCounter(0x0);
		}
	}
}

而在main.c中，则根据Sec的值来闪烁LED1灯。

	for(;;)
	{
		if(Sec == 1)
		{
			Sec = 0;
			GPIOA->ODR^=GPIO_Pin_8;
		}
	}

Test:

	for(;;)
	{
		if(Sec == 1)
		{
			Sec = 0;
			GPIOA->ODR^=GPIO_Pin_8;
		}
	}