实验5——485总线及Modbus通讯协议实验

课程名称：嵌入式软件技术开课机房：11号机房
2012年4月24日星期二8：10～11:35
一、实验任务与实验目的
二、报告内容
Freemodbus是modbus协议在嵌入式处理器上的实现。

包括AVR,PIC,WIN32等等平台。

它是开放性源代码，可用于商业目的。

它实现了Modbus RTU/ASCII、TCP三种传输方式，当前版本是1.5，支持以下功能：
∙读输入寄存器(0x04)
∙读保持寄存器(0x03)
∙写单个寄存器(0x06)
∙写多个寄存器(0x10)
∙读/写多个寄存器(0x17)
∙读取线圈状态(0x01)
∙写单个线圈(0x05)
∙写多个线圈(0x0F)
∙读输入状态(0x02)
∙报告从机标识(0x11)
本实现基于最新的标准并且与标准完全兼容。

接收和传输Modbus RTU/ASCII数据帧是通过一个由硬件提取层的调用来驱动状态机实现的。

这就使得协议非常容易移植到其他的平台之上。

当接收一个完整的数据帧后，该数据帧被传入Modbus应用层，数据帧的内容在该层内得到解析。

为方便地增加新的Modbus功能，Freemodbus在应用层提供了钩子函数Hooks。

如果用到了Modbus TCP协议，那么当准备处理一个新数据帧的时候，移植层就必须首先向协议层发送一个事件标志。

然后，协议栈调用一个返回值为接收到的Modbus TCP数据帧的函数，并且开始处理这个数据帧。

如果数据有效，则响应的Modbus反馈帧将提供给移植层生成反馈帧。

最后，该反馈帧被发送到客户端。

二、实现FreeModbus协议所需要的软/硬件需求
Modbus协议对硬件的需求非常少——基本上任何具有串行接口，并且有一些能够容纳modbus 数据帧的RAM的微控制器都足够了。

∙一个异步串行接口，能够支持接收缓冲区满和发送缓存区空中断。

∙一个能够产生RTU传输所需要的t3.5 字符超时定时器的时钟。

对于软件部分，仅仅需要一个简单的事件队列。

The STR71X/FreeRTOS 移植使用FreeRTOS 队列作为事件队列来减少Modbus 任务所需要的时间。

小点的微控制器往往不允许使用操作系统，在那种情况下，可以使用一个全局变量来实现该事件队列(The Atmel AVR 移植使用这种方式实现)。

实际的存储器需求决定于所使用的Modbus 模块的多少。

下表列出了所支持的功能编译后所需要的存储器。

ARM 项数值是使用GNUARM 编译器 3.4.4 使用-O1 选项得到的。

AVR项数值是使用WinAVR 编译器 3.4.5 使用-Os 选项编译得到的。

∙ATMega8/16/32/128/168/169 with WinAVR. See AVR/demo.c for an example.
Coldfire devices:
∙MCF5235 with GCC. See MCF5235/demo.c for an example.
∙MCF5235 with CodeWarrior and FreeRTOS port for ColdFire. See
MCF5235CW/demo.c for an example.
∙MCF5235/TCP with GCC. This port features FreeRTOS and the lwIP stack.
The lwIP part is generic and therefore it should be used as a basis for other
lwIP ports.
MSP430 devices
∙MSP430F169 with Rowley Crossworks. See MSP430/demo.c for an example.
∙MSP430F169 with GCC. See MSP430/demo.c for an example.
Z8Encore devices
∙Z8F6422 and Z8F1622 port. See Z8ENCORE/demo.c for an example. The port uses ZDS II - Z8 Encore! 4.10.1 as development environment.
Win32:
∙ A Win32 Modbus RTU/ASCII Port.
∙ A Win32 Modbus/TCP Port.
Linux:
∙ A Linux (uCLinux or other distributions) Modbus RTU/ASCII Port.
任务一
PortTimer.c中：xMBPortTimersInit( USHORT usTim1Timerout50us ) 负责配置一个时基，vMBPortTimersEnable( ) 启用这个时基。

比如执行:
xMBPortTimersInit( 10000 );
vMBPortTimersEnable( );
Port.c
/* ----------------------- System includes --------------------------------*/ #include"hw_types.h"
#include"interrupt.h"///zd
/* ----------------------- Modbus includes
----------------------------------*/
/* ----------------------- Variables
----------------------------------------*/
///int VIC_Temp;
/* ----------------------- Start implementation
-----------------------------*/
void EnterCriticalSection() {
IntMasterDisable(); /* Disable Interruptions _zd */
}
void ExitCriticalSection() {
IntMasterEnable(); /* Enable Interruptions _zd */
}
PortSerial.c
/*
* FreeModbus Libary: LM3S Port
* Copyright (C) 2007 Tiago Prado Lone <tiago@.br>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA *
* File: $Id: portserial.c,v 1.1 2007/04/24 23:15:18 wolti Exp $
*/
#include"hw_memmap.h"
#include"hw_ints.h"
#include"hw_types.h"
#include"sysctl.h"
#include"hw_uart.h"
#include"gpio.h"
#include"interrupt.h"
#include"uart.h"
/*-------------------------------------------------------------*/
#include"port.h"
/* ----------------------- Modbus includes
----------------------------------*/
#include"mb.h"
#include"mbport.h"
/* ----------------------- Start implementation
-----------------------------*/
void vMBPortSerialEnable(BOOL xRxEnable, BOOL xTxEnable) { if (TRUE == xRxEnable) {
UARTIntEnable(UART0_BASE, UART_INT_RX | UART_INT_RT);
} else {
UARTIntDisable(UART0_BASE, UART_INT_RX | UART_INT_RT);
}
if (TRUE == xTxEnable) {
UARTIntEnable(UART0_BASE, UART_INT_TX);
} else {
UARTIntDisable(UART0_BASE, UART_INT_TX);
}
}
void vMBPortClose(void) {
UARTIntDisable(UART0_BASE, UART_INT_RX | UART_INT_RT | UART_INT_TX);
IntEnable (INT_UART0);
}
BOOL xMBPortSerialInit(UCHAR ucPORT, ULONG ulBaudRate, UCHAR ucDataBits, eMBParity eParity) {
/*
UCHAR PORT;
ULONG BaudRate;
UCHAR DataBits;
eMBParity Parity;
PORT = ucPORT;
BaudRate = ulBaudRate;
DataBits = ucDataBits;
Parity = eParity;
*/
SysCtlPeripheralEnable (SYSCTL_PERIPH_UART0);
SysCtlPeripheralEnable (SYSCTL_PERIPH_GPIOA);
GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
// Configure the UART for ulBaudRate, 8-EVEN-1 operation.
UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), ulBaudRate,
(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |
UART_CONFIG_PAR_EVEN));
// Enable the UART interrupt.
IntEnable (INT_UART0);
UARTIntEnable(UART0_BASE, UART_INT_RX | UART_INT_RT | UART_INT_TX);
return TRUE;
}
BOOL xMBPortSerialPutByte(CHAR ucByte) {
UARTCharPutNonBlocking(UART0_BASE, ucByte);
return TRUE;
}
BOOL xMBPortSerialGetByte(CHAR * pucByte) {
*pucByte = UARTCharGetNonBlocking(UART0_BASE);
return TRUE;
}
/*
* Create an interrupt handler for the transmit buffer empty interrupt
* (or an equivalent) for your target processor. This function should then * call pxMBFrameCBTransmitterEmpty( ) which tells the protocol stack that * a new character can be sent. The protocol stack will then call
* xMBPortSerialPutByte( ) to send the character.
*/
static void prvvUARTTxReadyISR(void) {
pxMBFrameCBTransmitterEmpty();
}
/*
* Create an interrupt handler for the receive interrupt for your target
* processor. This function should then call pxMBFrameCBByteReceived( ). The * protocol stack will then call xMBPortSerialGetByte( ) to retrieve the
* character.
*/
static void prvvUARTRxISR(void) {
pxMBFrameCBByteReceived();
}
// UART INT HANDLER ZD
void UART0IntHandler(void) {
unsigned long ulStatus;
ulStatus = UARTIntStatus(UART0_BASE, true);
UARTIntClear(UART0_BASE, ulStatus);
if (ulStatus & (UART_INT_RT | UART_INT_RX)) {
prvvUARTRxISR();
}
if (ulStatus & UART_INT_TX) {
prvvUARTTxReadyISR();
}
}
/*
* FreeModbus Libary: LM3S Port
* Copyright (C) 2007 Tiago Prado Lone <tiago@.br>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA *
* File: $Id: porttimer.c,v 1.1 2007/04/24 23:15:18 wolti Exp $
*/
PortTimer.c
#include"hw_memmap.h"
#include"hw_ints.h"
#include"hw_types.h"
#include"sysctl.h"
#include"interrupt.h"
#include"hw_timer.h"
#include"hw_types.h"
#include"gpio.h"
#include"timer.h"
/* ----------------------- Platform includes
--------------------------------*/
#include"port.h"
/* ----------------------- Modbus includes
----------------------------------*/
#include"mb.h"
#include"mbport.h"
/* ----------------------- Start implementation
-----------------------------*/
BOOL xMBPortTimersInit(USHORT usTim1Timerout50us) { SysCtlPeripheralEnable (SYSCTL_PERIPH_TIMER0);
GPIOPinTypeTimer(TIMER0_BASE, TIMER_A);
TimerConfigure(TIMER0_BASE, TIMER_CFG_32_BIT_PER);
TimerLoadSet(TIMER0_BASE, TIMER_A,
(SysCtlClockGet() / 20000) * usTim1Timerout50us);
TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
TimerEnable(TIMER0_BASE, TIMER_A);
IntEnable (INT_TIMER0A);
return TRUE;
}
void vMBPortTimersEnable() {
TimerEnable(TIMER0_BASE, TIMER_A);
}
void vMBPortTimersDisable() {
TimerDisable(TIMER0_BASE, TIMER_A);
}
void TIMERExpiredISR(void) {
(void) pxMBPortCBTimerExpired();
}
// TIME0 INT HANDLER ZD
void Timer0IntHandler(void) {
TIMERExpiredISR();
TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT);
TimerEnable(TIMER0_BASE, TIMER_A);
}
PortEvent.c
/*
* FreeModbus Libary: LM3S Port
* Copyright (C) 2007 Tiago Prado Lone <tiago@.br>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA *
* File: $Id: portevent.c,v 1.1 2007/04/24 23:15:18 wolti Exp $
*/
/* ----------------------- Modbus includes
----------------------------------*/
#include"mb.h"
#include"mbport.h"
/* ----------------------- Variables
----------------------------------------*/
static eMBEventType eQueuedEvent;
static BOOL xEventInQueue;
/* ----------------------- Start implementation -----------------------------*/
BOOL xMBPortEventInit(void) {
xEventInQueue = FALSE;
return TRUE;
}
BOOL xMBPortEventPost(eMBEventType eEvent) { xEventInQueue = TRUE;
eQueuedEvent = eEvent;
return TRUE;
}
BOOL xMBPortEventGet(eMBEventType * eEvent) { BOOL xEventHappened = FALSE;
if (xEventInQueue) {
*eEvent = eQueuedEvent;
xEventInQueue = FALSE;
xEventHappened = TRUE;
}
return xEventHappened;
}。