MSP430F149單片機驅(qū)動DS2762讀寫操作C語言程序
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//#include
#define uchar unsigned char
#define uint unsigned int
uint A,B,C,D,E,F,G,H,I,J;//此處對io430x14x中的宏定義C進行了注釋，需注意
#define IO_OUT P3DIR |= BIT0;
#define IO_INP P3DIR &= ~BIT0;
uint data;
/******************************************************************************
對讀寫時間進行規(guī)范化
初始調(diào)試采用standard=1的參數(shù)
// Pause for exactly tick number of ticks = 0.25us
實際測的A延時14Us
B125US
******************************************************************************/
void SetSpeed(uint standard)
{
// Adjust tick values depending on speed
if (standard)
{
// Standard Speed
A = 6 * 4 / 2;
B = 64 * 4 / 2;
C = 60 * 4 / 2;
D = 10 * 4 / 2;
E = 9 * 4 / 2;
F = 55 * 4 / 2;
G = 0 / 2;
H = 480 * 4 / 2;
I = 70 * 4 / 2;
J = 410 * 4 / 2;
}
else
{
// Overdrive Speed
A = 1.5 * 4;
B = 7.5 * 4;
C = 7.5 * 4;
D = 2.5 * 4;
E = 0.75 * 4;
F = 7 * 4;
G = 2.5 * 4;
H = 70 * 4;
I = 8.5 * 4;
J = 40 * 4;
}
}
/******************************************************************************
延時程序
注意，需要選用8M晶振，時鐘周期125ns
******************************************************************************/
void tickDelay(uint tick) // Implementation is platform specific
{
for(;tick>0;tick--);
}
/******************************************************************************
主機復位脈沖
當接收結果result為0時，表明從機應答
******************************************************************************/
uchar OWTouchReset(void)
{
uchar result;
IO_OUT;
tickDelay(G);
P30 = 0; // Drives DQ low
tickDelay(H);
P30 = 1; // Releases the bus
tickDelay(I);
IO_INP;
result = P3IN & 0X01; // Sample for presence pulse from slave
tickDelay(J); // Complete the reset sequence recovery
return result; // Return sample presence pulse result
}
/******************************************************************************
像寫DS2762寫入一位
Send a 1-Wire write bit. Provide 10us recovery time.
******************************************************************************/
void OWWriteBit(uchar bit)
{
if (bit)
{
// Write 1 bit
P30 = 0; // Drives DQ low
tickDelay(A);
P30 = 1; // Releases the bus
tickDelay(B); // Complete the time slot and 10us recovery
}
else
{
// Write 0 bit
P30 = 0; // Drives DQ low
tickDelay(C);
P30 = 1; // Releases the bus
tickDelay(D);
}
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