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>>Drew的主頁---->程序示例
程序示例
這里是一些程序示例和源碼解釋.一些相關(guān)程序代碼會陸續(xù)補上.相關(guān)問題可參見硬件驅(qū)動
系統(tǒng)初始化
系統(tǒng)初始化對不同的CPU,基本步驟是類似的.
系統(tǒng)初始化的主要步驟如下
- 啟動
- 關(guān)閉中斷
- 放boot type到堆棧
- 清空緩存
VxWorks 系統(tǒng)的 PowerPC BSP,系統(tǒng)開機后執(zhí)行的第一個函數(shù) romInit(),在ROM的起點,這里是使用的PowerPC匯編語言
/* 定義內(nèi)部函數(shù) internals */
.globl romInit /* start of system code */
.globl _romInit /* start of system code */
/* 定義外部函數(shù) externals */
.extern romStart /* system initialization routine */
.text
.align 2
/*******************************************************************************
*
* romInit ( int startType /@ only used by 2nd entry point @/ )
*/
romInit:
_romInit:
bl cold /* 冷啟動 */
bl warm /* 熱啟動 */
cold:
li p5, BOOT_COLD
bl start /* skip over next instruction */
warm:
or p5, p0, p0 /* startType to p5 */
start: /* 此處是系統(tǒng)啟動開始 */
/* 屏蔽MSR中CE,EE位,關(guān)閉所有的外部中斷
/*
* Disable external interrupts
*/
mfmsr p0 /* p0 = msr */
INT_MASK (p0, p1) /* mask EE and CE bit */
ori p1,p1,_PPC_MSR_ME /* enable machine checks */
mtmsr p1 /* msr = p1 */
isync
/* 下面兩步是按照硬件定義初始化一些SPR,DCR寄存器,置0或置1
/* SPR是特殊功能寄存器,DCR為設(shè)備控制寄存器,還有MSR機器狀態(tài)寄存器,這些是PowerPC內(nèi)核中很重要的寄存器
/* 初始化SPR,DCR寄存器置0
* Initalize registers that need to be set to zero.
*/
addi r4,r0,0x0000
mtspr SGR,r4 /* 解鎖所有存儲區(qū)域 SPR 中 SGR 位置0 */
mtspr ESR, r4 /* SPR中的錯誤狀態(tài)位 ESR 清0 */
mtspr TCR, r4 /* 關(guān)閉所有的 timers */
mtspr PIT, r4 /* 清0 PIT timer */
mtdcr UICER, r4 /* 關(guān)閉中斷控制器(UIC)中的所有中斷 */
mtspr XER, r4 /* 清0 integer exception 寄存器 */
/* 初始化另一些SPR,DCR寄存器置1
* Initalize registers that need to be cleared with 0xFFFFFFFF.
*/
addis r4,r0,0xffff
ori r4,r4,0xffff
mtspr TSR, r4 /* timer */
mtspr DBSR, r4 /* 調(diào)試狀態(tài)位置1 */
mtdcr UICSR, r4 /* 清除中斷控制器(UIC)中的所有 pending 中斷 */
mtdcr dmasr, r4 /* DMA狀態(tài)寄存器置1 */
/* PowerPC405用兩個緩存,一個是16K指令緩存(ICU),一個是6K數(shù)據(jù)緩存(DCU),下面是清空著兩個緩存,并根據(jù)硬件設(shè)置緩存 */
/* 清空指令緩存 */
/*BESR type regs ZZZZZZZZZZZZ
* Invalidate the entire instruction cache. This can be done
* with a single iccci instruction in the processor core.
*/
iccci r0, r0
/*清空數(shù)據(jù)緩存
* Invalidate the entire data cache.
* The 405 processor core in the 405GP has 128 congruence classes.
* Each cache line in the 405 processor is 32 bytes.
*/
/*
* Turn the instruction cache on for faster boot-up.
* Also, the icache is needed to help initialize Bank 0
* of the EBC to speed up accesses to flash.
* address space 0x00000000-0x07ffffff is cached
* address space 0xf8000000-0xffffffff is cached
*/
lis p0, HIADJ(_PPC403_ICCR_DEFAULT_VAL)
addi p0, p0, LO(_PPC403_ICCR_DEFAULT_VAL)
mtspr _PPC403_ICCR, p0
isync
/* 初始化外部總線控制器(EBC),跳轉(zhuǎn)指令BL,執(zhí)行extBusCntlrInit
* /
bl extBusCntlrInit
/*
* Now that the EBC Bank 0 has been set up, turn the I-cache off if
* i-cache was not specified in config.h. It is also invalidated
* again.
*/
#ifndef USER_I_CACHE_ENABLE
li p0, 0 /* clear p0 */
mtspr _PPC403_ICCR, p0 /* turn off i-cache */
isync
iccci r0, r0 /* invalidate the I-cache again */
#endif
/* 初始化和SDRAM相關(guān)的IIC(inter-integrated circut)寄存器IIC0,
* Initialize IIC0 for use in automatic SDRAM configuration
*/
#ifdef LOCAL_MEM_AUTOSIZE
bl iic0Init
#endif
/* 初始化SDRAM,BL跳轉(zhuǎn)執(zhí)行sdramInit
* Configure the SDRAM controller only if this is a cold boot.
* If the SDRAM controller is reinitialized on a warm boot, the
* boot line will get wiped out because of the ECC SDRAM memory
* initialization.
*/
li p0, BOOT_COLD
and. p0, p0, p5 /* p5 is saved at the entry of romInit */
beq skip
bl sdramInit
skip:
/*
* Clear the CPU reservation bit
*/
li r0, 0
lwarx p0, r0, r0
stwcx. p0, r0, r0
#ifdef PPC405GP_REVA
/* 設(shè)置中斷向量表到0x0000 */
li p0, 0x2100/4
mtctr p0
lis p0, WALNUT_EVPR_VAL
li p1, 0x0000
zeroOut:
stw p1,0x0(p0)
addi p0, p0, 4
bdnz zeroOut
#endif
/* 初始化堆棧
/* Initialize the stack pointer (r1) */
lis sp, HIADJ(STACK_ADRS)
addi sp, sp, LO(STACK_ADRS)
#if FALSE /* SDA not supported */
/* initialize r2 and r13 according to EABI standard */
lis r2, HIADJ(_SDA2_BASE_)
addi r2, r2, LO(_SDA2_BASE_)
lis r13, HIADJ(_SDA_BASE_)
addi r13, r13, LO(_SDA_BASE_)
#endif
/* 得到C程序romStart()在ROM中的地址,保證romInit執(zhí)行結(jié)束后,系統(tǒng)跳轉(zhuǎn)執(zhí)行romStart()
/* calculate C entry point: routine - entry point + ROM base */
lis p1, HIADJ(romStart) /* p1 = romstart */
addi p1, p1, LO(romStart)
lis p2, HIADJ(romInit) /* p2 = romInit */
addi p2, p2, LO(romInit)
/* ROM_TEXT_ADRS為ROM的入口地址,在文件makefile定義,為0xfff80100
lis p3, HIADJ(ROM_TEXT_ADRS) /* p3 = ROM_TEXT_ADRS */
addi p3, p3, LO(ROM_TEXT_ADRS)
subf p1, p2, p1 /* p1 = p1 - p2 */
add p1, p1, p3 /* p1 = p1 + p3 */
/* p1中是romStart()的地址,這里把這個地址放到連接寄存器LR中. mtlr p1 /* link register = C entry point */
or p0, p5, p5 /* p0 = startType */
addi sp, sp, -FRAMEBASESZ /* get frame stack */
/* 跳轉(zhuǎn)到LR中romStart()的地址,執(zhí)行romStart()
blr /* branch to link register */
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硬件中斷
中斷的產(chǎn)生和VxWorks系統(tǒng)的中斷操作:
一般中斷的產(chǎn)生是由硬件定義的,如串口中斷的定義:
1.接收中斷:當(dāng)接收中斷使能,接收數(shù)據(jù)存儲器 RxData 存在有效數(shù)據(jù),則產(chǎn)生中斷.
2.發(fā)送中斷:當(dāng)發(fā)送中斷使能,發(fā)送數(shù)據(jù)存儲器 TxData 為空,則產(chǎn)生中斷.
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硬件發(fā)送中斷產(chǎn)生邏輯示意 |
硬件接收中斷產(chǎn)生邏輯示意 |
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所以要產(chǎn)生一個串口中斷,主要有兩步:
1.使能這兩個串口中斷,RX Enable,TX Enable,函數(shù)intEnable().
2.用intConnect()登記中斷號,和相應(yīng)的中斷例程ISR.
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程序示例
在VxWorks系統(tǒng)上登記,使能串口中斷
intConnect((VOIDFUNCPTR *)5,ComISR,0); //登記中斷服務(wù)程序ComISR()到外部中斷號5,
intEnable((VOIDFUNCPTR *)5); //使能外部中斷5
//enable 使能 UART1 這里直接用32位地址表示了
*(unsigned long *)0x20000014 &= ~0x01000100; //INT_FORCE use pending
*(unsigned long *)0x20000010 = 0x01000100; //INT_PENDING clear
*(unsigned long *)0x20000018 = 0x01000100; //INT_MASK only enable UART1 RX
//control register 使能 RX TX
*(unsigned long *)0x20000068 = 0x00070007; //RX and TX ENABLE
//divider register,baut rate 19200 設(shè)置波特率
*(unsigned long *)0x2000006c = 59;
//完成, 這樣當(dāng)串口有中斷發(fā)生時,硬件系統(tǒng)會自動跳轉(zhuǎn)到中斷號5的地址0x18,調(diào)用程序ComISP().
注意:中斷程序不能單步執(zhí)行,或跟蹤調(diào)試,中斷服務(wù)程序中與函數(shù)庫或系統(tǒng)有關(guān)的函數(shù)不可用如print()等,因為中斷調(diào)用時,所有其它的任務(wù)都被掛起停止運行.
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VxWorks系統(tǒng)的網(wǎng)絡(luò)驅(qū)動(END)
VxWorks網(wǎng)絡(luò)配置參見VxWorks網(wǎng)絡(luò)驅(qū)動配置及分析
VxWorks系統(tǒng)網(wǎng)絡(luò)驅(qū)動在BSP中完成,寫驅(qū)動時應(yīng)參考BSP develop kit,在VxWorks中叫做END( Enhanced Network Driver),編寫程序使用由VxWorks定義的MUX接口
MUX是數(shù)據(jù)鏈路層和網(wǎng)絡(luò)協(xié)議層之間的接口
主要調(diào)用過程和步驟如下:
VxWorks系統(tǒng)執(zhí)行的第一個任務(wù)target\config\all\usrConfig.c文件中 usrRoot()=======>>
target\src\config\usrNetwork.c文件(該文件初始化TCP/IP)中 usrNetInit(BOOT_LINE_ADRS)(該函數(shù)作用是添加MUX END)========>>
pcooki = pCookie = muxDevLoad(pDevTbl->unit,.....)其中pDevTbl在BSP網(wǎng)絡(luò)配置文件configNet.h中定義.END_TBL_ENTRY endDevTbl[]={...},該表定義了網(wǎng)絡(luò)設(shè)備的具體參數(shù),在這里調(diào)用了網(wǎng)絡(luò)驅(qū)動
END_TBL_ENTRY endDevTbl [] =
{
{0, IBM_EMAC_LOAD_FUNC, IBM_EMAC_LOAD_STR_0, TRUE, NULL, FALSE},
{0, END_TBL_END, NULL, 0, NULL, FALSE},
};
其中IBM_EMAC_LOAD_FUNC就是 ibmEmacEndLoad()
========>>muxDevStart(pcooki)==========>>ibmEmacEndLoad()
ibmEmacEndLoad()初始化系統(tǒng)為網(wǎng)絡(luò)驅(qū)動運行做準(zhǔn)備
MUX調(diào)用ibmEmacStart()
ibmEmacStart() 登記中斷服務(wù)程序ibmEmacInit(),啟動設(shè)備運行在中斷模式下.
LOCAL STATUS ibmEmacStart ( EMAC_DRV_CTRL * pDrvCtrl )
{
int rc;
SYS_INT_CONNECT (pDrvCtrl, ibmEmacInt, pDrvCtrl, &rc);
SYS_OUT_LONG(pDrvCtrl, EMAC_ISR, 0xFFFFFFFF);
SYS_INT_ENABLE ();
/* Allow MAL EOB and Descriptor error interrupts */
malChannelIntMaskSet(MAL_TX_TYPE, pDrvCtrl->txChn0MalChannel,
MAL_EOB_INT_EN | MAL_DE_INT_EN | MAL_SERR_INT_EN);
malChannelIntMaskSet(MAL_RX_TYPE, pDrvCtrl->rxChn0MalChannel,
MAL_EOB_INT_EN | MAL_DE_INT_EN | MAL_SERR_INT_EN);
return (OK);
}
中斷服務(wù)程序ibmEmacInit() 處理EMAC控制器的中斷,主要是 TX,RX狀態(tài)錯誤
LOCAL void ibmEmacInt ( EMAC_DRV_CTRL * pDrvCtrl )
{
UINT isrReg;
/* Read the EMAC interrupt status register */
SYS_IN_LONG(pDrvCtrl, EMAC_ISR, isrReg);
pDrvCtrl->errorEmac = isrReg;
/*
* Check to see if there was a TX error. If there was, the Dead bit
* will be set. Clear the status bits for the TX error, and clear the dead
* bit. Keep count of these errors in the main device structure.
*/
if (isrReg & EMAC_ISR_TX_INTS)
{
pDrvCtrl->intErrorTX++;
SYS_OUT_LONG(pDrvCtrl, EMAC_ISR, EMAC_ISR_TX_INTS);
}
/*
* Check to see if there was a RX error. Clear the status bits for the RX
* error. Keep count of these errors in the main device structure.
*/
if (isrReg & EMAC_ISR_RX_INTS)
{
pDrvCtrl->intErrorRX++;
SYS_OUT_LONG(pDrvCtrl, EMAC_ISR, EMAC_ISR_RX_INTS);
}
return;
}
(未完)
Cillus網(wǎng)卡CS8900A Linux驅(qū)動
下面是我為一個網(wǎng)友解釋的CS8900A網(wǎng)卡驅(qū)動文件中的部分函數(shù),操作系統(tǒng)為ucLinux,CPU是國內(nèi)常用的Motorola龍珠系列MC68EZ328(16M),相比PowerPC和ARM來說,它的結(jié)構(gòu)簡單,不帶MMU,較易理解
CS8900A是一個16位網(wǎng)卡,支持ISA總線,10-BastT.
static inline void outw(unsigned short value,unsigned int addr)
{
unsigned short newvalue;
unsigned char *_src=(unsigned char*)(&value),*_dest=(unsigned char*)(&newvalue);
//這里為什么要交換一下?
////++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//這里不是交換,而是賦值,將16位分成兩個8位的數(shù)組,分別賦值,16位寄存器是只有后8位可讀寫,
//前8位是寄存器ID,所以這里吧后8位放在前面"_dest[0]=_src[1];"
//然后通過I/O口,賦給相應(yīng)的存儲器,即"*(volatile unsigned short*)addr=newvalue;"
///+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_dest[0]=_src[1];
_dest[1]=_src[0];
*(volatile unsigned short*)addr=newvalue;
}
static int cs89x0_probe1(struct device *dev, int ioaddr)
{
struct net_local *lp;
static unsigned version_printed = 0;
int i;
unsigned rev_type = 0;
irq2dev_map[0] = dev;
/* set up the chip select */
//下面這一段該怎么理解?看不懂阿
////++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//這里是對CPU進行操作,對cs89進行初始化,我沒有見到你的硬件原理圖,我只能按CPU
//的結(jié)構(gòu)定義來解釋一下,你要想搞清楚,只有看硬件原理圖,還要參考CPU的硬件手冊
////++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//連通PORT F I/O功能管腳1,SEL1(-IRQ5/PF1),
*(volatile unsigned char *)0xfffff42b |= 0x02; /* output /sleep */
//設(shè)置PORT F 管腳0為輸出,輸出高電平
*(volatile unsigned short *)0xfffff428 |= 0x0101; /* not sleeping */
//連通PORT F 中斷功能管腳1,SEL1(-IRQ5/PF1)
*(volatile unsigned char *)0xfffff42b &= ~0x02; /* input irq5 */
//PORT F 管腳1,SEL1(-IRQ5/PF1) 為輸入方式,置低電平有效
*(volatile unsigned short *)0xfffff428 &= ~0x0202; /* irq5 fcn on */
//在寄存器CSGBB中定義片選及cs89的基地址為:0x10000000.++++非常重要+++++++
*(volatile unsigned short *)0xfffff102 = 0x8000; /* 0x04000000 */
//在寄存器CSB中,片選使能,cs89地址空間大小(1M),數(shù)據(jù)線寬16位,6個等待周期,FLASH...,
//非保護存儲空間(128K)......
*(volatile unsigned short *)0xfffff112 = 0x01e7; /* 128k, 2ws, FLASH, en */
//對PORT G操作........
*(volatile unsigned int *)0xfffff430 = 0x023c3d0a;
////++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//這是I/O模式的主要的兩個PORT口,一個是地址口,一個是數(shù)據(jù)口,這里對0x22操作,
//中斷IRQ0
///+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
*(volatile unsigned short*)0x1000030a=0x2200;
*(volatile unsigned short*)0x1000030c=0;
//*(volatile unsigned short *)0xfffff302 |= 0x0080;
......................
.....................
void
reset_chip(struct device *dev)
{
int reset_start_time;
writereg(dev, PP_SelfCTL, readreg(dev, PP_SelfCTL) | POWER_ON_RESET);
/* wait 30 ms */
current->state = TASK_INTERRUPTIBLE;
current->timeout = jiffies + 3;
schedule();
/* Wait until the chip is reset */
//這里jiffies說是timestamp,時間標(biāo)記,這個變量和current
//都在哪里定義?
//jiffies主要起什么作用?
////+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//這里是個延時等待,reset以后必須有等待,以便reset徹底完成,在reset過程中所有寄存器是關(guān)閉的
//不但對cs89,對其他芯片也是一樣的
///++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ reset_start_time = jiffies;
while( (readreg(dev, PP_SelfST) & INIT_DONE) == 0 && jiffies - reset_start_time< 2);
}
static int
net_open(struct device *dev)
{
struct net_local *lp = (struct net_local *)dev->priv;
int result = 0;
int i;
write_irq(dev, lp->chip_type, 0);
irq2dev_map[/* FIXME */ 0] = dev;
writereg(dev, PP_BusCTL, 0); /* ints off! */
//這里和上面那個一樣,怎么看懂?
////++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//這里也是CPU對CS89操作,我也根據(jù)CPU硬件手冊給你大概說一下
///+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//中斷信號,正電平觸發(fā)(POL5)
*(volatile unsigned short *)0xfffff302 |= 0x0080; /* +ve pol irq */
//調(diào)整PORT G的輸入輸出狀態(tài),及設(shè)置管腳相應(yīng)的電平信號
*(volatile unsigned int *)0xfffff430 = 0x023c3d0a; /* low -> high */
*(volatile unsigned int *)0xfffff430 = 0x023e3d0a;
*(volatile unsigned int *)0xfffff430 = 0x023c3d0a; /* high -> low */
////++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//這是I/O模式的主要的兩個PORT口,一個是地址口,一個是數(shù)據(jù)口,這里對0x22操作,
//中斷IRQ0
///+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
*(volatile unsigned short *)0x1000030a = 0x2200; /* index window, REG index : 0022h */
*(volatile unsigned short *)0x1000030c = 0x0000; /* data window, REG data : 0000h,irq0 */
.........................
.........................
static void
net_rx(struct device *dev)
{
struct net_local *lp = (struct net_local *)dev->priv;
int ioaddr = dev->base_addr;
struct sk_buff *skb;
int status, length;
//下面兩行怎么右邊是一樣的?
//是作者寫錯了嗎?
////++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++|
//不是,這是一個包中前后不同的兩個數(shù)據(jù),前一個數(shù)據(jù)是該數(shù)據(jù)包的狀態(tài),后一個是數(shù)據(jù)包的長度
////++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
status = inw(ioaddr + RX_FRAME_PORT);
length = inw(ioaddr + RX_FRAME_PORT);
if ((status & RX_OK) == 0) {
lp->stats.rx_errors++;
if (status & RX_RUNT) lp->stats.rx_length_errors++;
if (status & RX_EXTRA_DATA) lp->stats.rx_length_errors++;
if (status & RX_CRC_ERROR) if (!(status & (RX_EXTRA_DATA|RX_RUNT)))
/* per str 172 */
lp->stats.rx_crc_errors++;
if (status & RX_DRIBBLE) lp->stats.rx_frame_errors++;
return;
}
......................
static int
set_mac_address(struct device *dev, void *addr)
{
int i;
if (dev->start)
return -EBUSY;
if(get_arena_addr())
{
memcpy(dev->dev_addr,0x1100000,6);
}
else
{
//這里的00hhcnl和前面
//出現(xiàn)的00hhcn是什么意思?
////+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//注意:在這里他更改了網(wǎng)卡的MAC值,隨便給了一個值"0x00,0x00,‘h‘,h‘,‘c‘,‘n‘",
//不過這個48位值必須是世界唯一的,或者用網(wǎng)卡自帶的也可以.我不能確定是否eeprom中有信息,
//你可以用示波器量一下EEDI管腳,若為高電平,則EEPROM用到了,否則,他們根本沒有用EEPROM.
///++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
unsigned char mac[]={0,0,‘h‘,‘h‘,‘c‘,‘n‘};
memcpy(dev->dev_addr,mac,6);
}
printk("%s: Setting MAC address to ", dev->name);
for (i = 0; i < 6; i++)
printk(" %2.2x", dev->dev_addr[i] = ((unsigned char *)addr)[i]);
printk(".\n");
/* set the Ethernet address */
for (i=0; i < ETH_ALEN/2; i++)
writereg(dev, PP_IA+i*2, dev->dev_addr[i*2] | (dev->dev_addr[i*2+1] << 8));
return 0;
}
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LCD 與觸摸屏
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Modem撥號
Modem撥號程序步驟如下
1. off hook,發(fā)出摘機命令(ATH1\r),
等待modem返回狀態(tài),如果是"OK",則表示成功.進行第二步.
2. on hook 發(fā)出掛機命令(ATH\r),
等待modem返回狀態(tài),如果是"OK",則表示成功.進行第三步.
3. off hook,dialing,摘機撥號(ATDT....\r),
等待modem返回狀態(tài),如果是"CONNECT",則表示成功.進行第四步.
4. send data,發(fā)送數(shù)據(jù).
最好按上述步驟一步一步調(diào),并要等待正確的返回值后再進行下一步.
具體程序例子如下,撥號:
// 清空接收FIFO
REG(FCR, nsChan) |=FCR_RXCLR;
// 等待,直到清空為止
while((REG(FCR, nsChan) & FCR_RXCLR) != 0x00);
// 撥號
while(atdt1[i]!=0)
{
// 檢查發(fā)送FIFO是否準(zhǔn)備好,為空
while((REG(LSR, nsChan) & LSR_THRE) == 0x00);
// 在發(fā)送FIFO中放入數(shù)據(jù)
REG(THR, nsChan) = atdt1[i];
i++;
}
// 等待是否有數(shù)據(jù)到達,即modem返回數(shù)據(jù).
while((REG(LSR, nsChan) & LSR_DR) == 0x00);
// 接收數(shù)據(jù)并判斷返回值
response[i-19]=REG(RBR,nsChan);
if(response[0]!=0x43)
..................
else
..................
// 如果返回值是"connect",
while(*data!=0)
{
while((REG(LSR, nsChan) & LSR_THRE) == 0x00);
REG(THR, nsChan) = *data++;
}
其他步驟基本一樣.
這是在ARM7上做的modem驅(qū)動,硬件設(shè)計方法是modem集成在主板上,沒有用串口,modem是用片選地址直接對硬件操作的.
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