📄 at45db041b.lst
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C51 COMPILER V7.06 AT45DB041B 08/28/2008 17:06:38 PAGE 1
C51 COMPILER V7.06, COMPILATION OF MODULE AT45DB041B
OBJECT MODULE PLACED IN AT45DB041b.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE AT45DB041b.c OMF2 BROWSE DEBUG
stmt level source
1 /******************************************************************************
2 at45db041b特性：
3 正常操作电压为2.7~3.6V，实验中发现当电压超过4.25V后读出的状态字节为9A（正常
4 的状态字节值为9D），并且读写数据均不准确，所以应当保证卡片的供电电压不超过
5 4.25V。
6 SPI规范：
7 Data is always clocked into the device on the rising edge of SCK a-
8 nd clocked out of the device on the falling edge of SCK.All instruction-
9 s,addresses and data are transferred with the most significant bit(MSB)
10 first.
11 2005-06-02
12 /******************************************************************************/
13 #include "reg51.h"
14 #include "at45db041b.h"
15
16 sbit SPI_CS = P2^0;
17 sbit SPI_SCK = P2^2;
18 sbit SPI_SO = P2^3;
19 sbit SPI_SI = P2^4;
20
21 unsigned char SPI_HostReadByte(void) {
22 1 unsigned char i, rByte = 0;
23 1 for(i = 0; i < 8; i++){
24 2 SPI_SCK = 0;
25 2 SPI_SCK = 1;
26 2 rByte <<= 1;
27 2 rByte |= SPI_SO;
28 2 }
29 1 return rByte;
30 1 }
31
32 void SPI_HostWriteByte(unsigned char wByte) {
33 1 unsigned char i;
34 1 for(i = 0; i < 8; i++) {
35 2 if((wByte << i) & 0x80) {
36 3 SPI_SI = 1;
37 3 }
38 2 else {
39 3 SPI_SI = 0;
40 3 }
41 2 SPI_SCK = 0;
42 2 SPI_SCK = 1;
43 2 }
44 1 }
45
46 /******************************************************************************
47 描述：
48 When the end of a buffer is reached.the device will continue reading back at
49 the beginning of the buffer.
50 参数：
51 buffer - 指定buffer ID-1、2
52 BFA - 指定BUFFER中的起始写入地址
53 pHeader - 指定存储数据的首地址
54 len - 指定数据的长度
55 /******************************************************************************/
C51 COMPILER V7.06 AT45DB041B 08/28/2008 17:06:38 PAGE 2
56 void AT45DB041B_BufferRead(UCHAR buffer, UINT BFA, UCHAR *pHeader, UINT len) {
57 1 unsigned int i = 0;
58 1 while(i++ < 255) {
59 2 if(AT45DB041B_StatusRegisterRead() & 0x80) {
60 3 break;
61 3 }
62 2 }
63 1 SPI_CS = 0;
64 1 switch(buffer) {
65 2 case 1 : SPI_HostWriteByte(Read_Buffer1);//#define Write_Buffer1 0x84
66 2 break;
67 2 case 2 : SPI_HostWriteByte(Read_Buffer2);////#define Write_Buffer2 0x87
68 2 break;
69 2 }
70 1 SPI_HostWriteByte(0x00);//the don't care 15bits of high eight bits
71 1 SPI_HostWriteByte((unsigned char)(BFA >> 8));//the don't care 15bits of low seven bits and the BFA of hig
-h one bit
72 1 SPI_HostWriteByte((unsigned char)BFA);//the BFA of low eight bits
73 1 SPI_HostWriteByte(0x00);//the eight don't care bits
74 1 for(i = 0; i < len; i++) {
75 2 pHeader[i] = SPI_HostReadByte();
76 2 }
77 1 SPI_CS = 1;
78 1 }
79
80 /******************************************************************************/
81 /*Status Register Format: */
82 /* ----------------------------------------------------------------------- */
83 /* | bit7 | bit6 | bit5 | bit4 | bit3 | bit2 | bit1 | bit0 | */
84 /* |--------|--------|--------|--------|--------|--------|--------|--------| */
85 /* |RDY/BUSY| COMP | 0 | 1 | 1 | 1 | X | X | */
86 /* ----------------------------------------------------------------------- */
87 /* bit7 - 忙标记，0为忙1为不忙。 */
88 /* 当Status Register的位0移出之后，接下来的时钟脉冲序列将使SPI器件继续*/
89 /* 将最新的状态字节送出。 */
90 /* bit6 - 标记最近一次Main Memory Page和Buffer的比较结果，0相同，1不同。 */
91 /* bit5 */
92 /* bit4 */
93 /* bit3 */
94 /* bit2 - 这4位用来标记器件密度，对于AT45DB041B，这4位应该是0111，一共能标记 */
95 /* 16种不同密度的器件。 */
96 /* bit1 */
97 /* bit0 - 这2位暂时无效 */
98 /******************************************************************************/
99 unsigned char AT45DB041B_StatusRegisterRead(void) {
100 1 unsigned char status;
101 1 SPI_CS = 0;
102 1 SPI_HostWriteByte(Status_Register_Read);//#define Status_Register_Read 0xd7//写入读取AT45DB041B状态寄存
-器命令'0xd7'
103 1 status = SPI_HostReadByte();
104 1 SPI_CS = 1;
105 1 return status;
106 1 }
107
108 /******************************************************************************
109 描述：
110 When the last bit in the main memory array has been read,the device will
111 continue reading back at the beginning of the first page of memory.As w-
112 ith crossing over page boundaries,no delays will be incurred when wrapp-
113 ing around from the end of the array to the beginning of the array.
114 参数：
115 PA - 页地址，0~2047
C51 COMPILER V7.06 AT45DB041B 08/28/2008 17:06:38 PAGE 3
116 BFA - 指定BUFFER中的起始写入地址
117 pHeader - 指定数据的首地址
118 len - 指定数据的长度
119 /******************************************************************************/
120 void AT45DB041B_ContinuousArrayRead(UINT PA, UINT BFA, unsigned char *pHeader, UINT len) {
121 1 unsigned int i = 0;
122 1 while(i++ < 255) {//i++ < 255用来延时等待AT...空闲
123 2 if(AT45DB041B_StatusRegisterRead() & 0x80) {//读取状态寄存器最高位,判断是否为忙
124 3 break;//为1表示空闲则跳出
125 3 }
126 2 }
127 1 SPI_CS = 0;
128 1 SPI_HostWriteByte(Continuous_Array_Read);//#define Continuous_Array_Read 0xe8//连续的数组读取
129 1 SPI_HostWriteByte((unsigned char)(PA >> 7));//此处代码很妙啊,PA >> 7则是发送PA的高4位以及最开始的4位无⌨️ 快捷键说明
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