求助 关于一些题目

ziyougang

求助 关于一些题目 [复制链接]

 

2.you are communicating with an external device over an I²C bus. The I²C address of the device is 0x40. list the steps you would take to write a 1 in bit 7 of a register at address 02 in the external device without affecting the other bits in that register. You can assume you are using an I²C controller to do the actual I²C bus operations as in the next example. (you will essentially write program comments with appropriate values but you do not need to write the actual assembly language instructions)

       LDR R10,=0x40301688

@read from register 02 from the I2C device adressed in 0x40

 

    MOV R0,#0X80        @slave adress in the I2C bus is 0x40;

    STR R0,[R10]

    MOV R0,#0x69        @set byte to start a read after write cycle

    STR R0,[R10,#0x8]

    BL POLLTB

 

    MOV R0,#0X02    @要读入器件内部地址02单元

    STR R0,[R10]

    MOV R0,#0X68

    STR R0,[R10,#0X8]

    BL POLLTB

 

    MOV R0,#0X81    @设置读入周期@

    STR R0,[R10]

    MOV R0,#0x69    @START=1,STOP=0,TB=1@

    STR R0,[R10,#0x8]

    BL POLLTB

 

    MOV R0,#0X6A    @只读一个数据@stop=1 TB=1

    STR R0,[R10,#0X8]   @设置开始读入@

    BL POLLTB       @等待读入结束

 

 

 

 

 

    LDR R1,[R10]

    MOV R2,#0X80

    ORR R1,R1,R2

 

 

 

 

 

 

    MOV R0,#0X80

    STR R0,[R10]

    MOV R0,#0x69

    STR R0,[R10,#0x8]

    BL POLLTB@

 

    MOV R0,#0X02    @写入器件内部地址02单元

    STR R0,[R10]

    MOV R0,#0X68

    STR R0,[R10,#0X8]

    BL POLLTB

   

    MOV R0,R1   @这是写入器件02单元的数据@

    STR R0,[R10]

    MOV R0,#0X6A    @写入后停止,只写一个数据@

    STR R0,[R10,#0X8]

    BL POLLTB       @等响应

 这个题目根据上面的程序。。怎么写算法啊

 

3.briefly describe the operation of a Successive Approximation type A/D converter and in general terms compare its speed with that of the other types of converters( flash , dual slope, sigma-delta)

 

4.describe why a low-pass filter is often put in series with the input of an A/D converter that is to be used to digitize rapidly changing signals such as audio frequency sinewave signals.

 

5.describe the meaning of five of the following terms.

  a. CRC

  b. half-duplex

  c.  snubber circuit

  d. Quantization Error

  e. sigma-delta A/D converter
这题给点中文资料

njlianjian

1 你去看看iic的手册 你就知道算法了 你的这题很简单的 读数据而已 2 选择一个ad 去找找资料就可以了 sigma-delta A/D 这种converter很多就是速度慢点 精度还可以

破茧佼龙

我想说的楼上的都说了啊