MSP430F149单片机对SDRAM控制程序设计

MSP430的内核结构采用具有高透明格式的精简指令集（RISC）设计。指令分为硬件实现的内核指令和利用这一硬件结构的具有更高效率的模拟指令，使用起来非常方便。在本控制系统中，单片机完成初始化任务（设置标志位、看门狗的工作方式）后，就进入低功耗睡眠状态。中断将其唤醒，转而进入相应的子程序。基于MSP430F149单片机的SDRAM控制程序如下。

#include msp430x14x.h>

void Init(void);

void Send(char* Data, unsigned int Length);

void SendAddress(unsigned int Address);

void SendData(unsigned int Data);

unsigned int ReceiveData(void);

char ReadData[20], Buffer[20];

unsigned char i=0, j, k, flag=0;

unsigned int Data;

unsigned int DisplayData;

char DisplayString[20];

void main(void)

{

WDTCTL = WDTPW + WDTHOLD; // Stop WDT

Init(); // UART1 inition

_EINT(); // enable interrupt

while(1)

{

DisplayData = ReceiveData();

if (DisplayData == 0)

{

k = 0;

if (DisplayData != 0)

{

DisplayString[k] = 0 + DisplayData % 10;

DisplayData = DisplayData / 10;

k++;

}

Send(DisplayString, k);

}

}

}

void Init(void)

{

UCTL1 &= ~SWRST; // reset swrst and usart1 enable

UCTL1 = 0x10; // 8-bit character

UBR01 = 0x03; // 8MHz 38400

UBR11 = 0x00; // 8MHz 38400

UMCTL1 = 0x4A; // U1CLK = SMCLK=TX2

UTCTL1 = 0x10;

ME2 |= 0x30; // Enable USART1 TXD/RXD

P3SEL= 0xC0; // enable P3.6,7 USART1 TXD/RXD

P3DIR= 0x40; // P3.6 output direction

IE2 |= URXIE1; // Enable USART1 RX interrupt

}

interrupt [UART1RX_VECTOR] void UART1RX(void) // read data

{

if (flag == 0) // wait for strat char of "0xAA" or "0xDD"

{

if (RXBUF1 == 0xAA) // alter flag

{

flag = 1;

}

else if (RXBUF1 == 0xDD) // alter flag

{

flag = 2;

}

i = 0;

}

else

{

ReadData[i] = RXBUF1;

if (ReadData[i++] == 0xFF) // end char of "0xFF"

{

Data = 0;

for (j=i-1; j!=0; j--)

{

Data = Data * 10 + (ReadData[j] - 0);

}

if (flag == 1) // send address

{

SendAddress(Data);

}

else if (flag == 2) // send data

{

SendData(Data);

}

flag = 0;

}

}

}

void Send(char* Data, unsigned int Length) // send data

{

unsigned int i;

UCTL1 |= TXWAKE;

TXBUF1 = 0x01;

while ((UTCTL1&0x01) == 0);

UCTL1 &= ~TXWAKE;

for(i=0; i<=Length; i++)

{

TXBUF1 = Data[i];

while ((UTCTL1&0x01) == 0);

}

}

void SendAddress(unsigned int Address) // send address

{

// address buses

P1DIR |= 0xE0; // P1.5-1.7 address buses

P2DIR = 0xFF; // P2.0-2.7 address buses

P3DIR |= 0x1F; // P3.0-3.5 address buses

P4DIR |= 0x1F; // P4.0-4.5 address buses

P1OUT |= (Address & 0x07);

P2OUT |= (Address & 0x7F8) >> 3;

P3OUT |= (Address & 0x1F800) >> 11;

P4OUT |= (Address & 0x7E0000) >> 17;

}

void SendData(unsigned int Data) // send data

{

// data buses

P4DIR |= 0xC0; // P4.6-4.7 data buses

P5DIR |= 0x1F; // P5.0-5.5 data buses

P4OUT |= (Data & 0x03);

P5OUT |= (Data & 0xFC) >> 2;

}

unsigned int ReceiveData(void) // send data

{

unsigned int Data;

// data buses

P4DIR &= 0x3F; // P4.6-4.7 data buses

P5DIR &= 0xE0; // P5.0-5.5 data buses

Data = ((P5IN & 0x1F) < 2) | ((P4IN & 0xC0) >> 6);

return Data;

}