MSP430的内核结构选用具有高通明格局的精简指令集（RISC）规划。指令分为硬件完结的内核指令和运用这一硬件结构的具有更高功率的模仿指令，运用起来十分便利。在本控制系统中，单片机完结初始化使命（设置标志位、看门狗的工作方式）后，就进入低功耗睡觉状况。中止将其唤醒，转而进入相应的子程序。根据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;
}
