【HarmonyOS HiSpark Wi-Fi IoT 套件试用连载】五、显示板的使用

本文来源电子发烧友社区，作者：李元江， 帖子地址：https://bbs.elecfans.com/jishu_2021769_1_1.html

今天来写一篇关于使用显示板的帖子。主要完成温湿度传感器数据采集，把采集到的数据显示到OELD显示屏，显示时钟。

一、硬件介绍

通过查看环境监测板的原理图，发现该板子主要有两个种资源：12864OLED显示屏，两个模拟按键。两个模拟按键分别按下时，因为电阻分压，在SWITCH端的电压都一样，根据测量这个SWITCH端电压值，可以读取到按键的状态。

其中OLED兼容两种通信接口SPI和I2C,这里我选择使用I2C。

它们使用主控的GPIO口分别为：AHT20温湿度传感器SDA --》 GPIO13 可复用为I2C0_SDASCL --》 GPIO14 可复用为I2C0_SCL模拟按键ADC --》 GPIO05 可复用为ADC2

二、软件设计

1、新建文件

在wifi-iot/app目录下，新建OLED文件夹，存放与显示板和环境监测板相关的代码。所含文件如下所示。

其中aht20.c、aht20.h、envrionment_demo.c。是从上一篇帖子移植过来的，主要跟环境监测板有关。oled_demo.c 、oled_fonts.h 、 oled_ssd1306.h 、oled_ssd1306.c从许思维老师例程中移植过来。timeconv.c timeconv.h与时间转换有关。

2、timeconv.c

该c文件主要跟时间戳转换有关，在这个例程中，每一秒时间戳数值加1，然后再把时间戳转换为北京时间即可到的时间戳对应的北京时间。

1. #include "timeconv.h"
2. #include
3. #include
4. ​
5. static uint8_t month_day[12]={31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; //平年
6. static uint8_t Leap_month_day[12]={31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; //闰年
7. const uint16_t dayPerYear[4] = {365, 365, 365, 366};
9. // 判断是否是闰年
10. // year: 需要判断的年
11. // return：1：闰年
12. // 0: 平年
13. uint8_t isLeapYear(uint16_t year)
14. {
15. uint8_t res=0;
17. if(year%4 == 0) // 能够被4整除
18. {
19. if((year%100 == 0) && (year%400 != 0)) //能够被100整除，但是不能够被400整除
20. {
21. res = 0;
22. }
23. else
24. {
25. res =1;
26. }
27. }
28. return res;
29. }
31. // 将Unix时间戳转换为北京时间
32. // unixTime: 需要判断的Unix时间戳
33. // *tempBeijing:返回的北京时间
34. // return：none
35. // note：没对输入参数正确性做判断
36. void covUnixTimeStp2Beijing(uint32_t unixTime, rtc_time_t *tempBeijing)
37. {
38. uint32_t totleDaynum=0, totleSecNum=0;
39. uint16_t remainDayofYear;
40. uint8_t *pr, tempYear=0;
41. totleDaynum = (uint32_t)unixTime/(((uint32_t)24*60*60)); //总天数(注意加括号)
42. totleSecNum = (uint32_t)unixTime%((uint32_t)24*60*60); //当天剩余的秒速
43. memset(tempBeijing, 0x00, sizeof(rtc_time_t));
44. // 1.计算哪一年
45. tempBeijing->ui8Year = 1970 + (totleDaynum/((uint32_t)FOURYEARDAY))*4;
46. remainDayofYear = totleDaynum%((uint32_t)FOURYEARDAY)+1;
47. //Delay_1ms(1000);
48. while(remainDayofYear > dayPerYear[tempYear])
49. {
50. remainDayofYear -= dayPerYear[tempYear];
51. tempBeijing->ui8Year++;
52. tempYear++;
53. }
54. //2.计算哪一月的哪一天
55. pr = isLeapYear(tempBeijing->ui8Year)?Leap_month_day:month_day;
56. while(remainDayofYear > *(pr+tempBeijing->ui8Month))
57. {
58. remainDayofYear -= *(pr+tempBeijing->ui8Month);
59. tempBeijing->ui8Month++;
60. }
61. tempBeijing->ui8Month++; //month
62. tempBeijing->ui8DayOfMonth = remainDayofYear; //day
63. //3.计算当天时间
64. tempBeijing->ui8Hour = (totleSecNum)/3600;
65. tempBeijing->ui8Minute = (totleSecNum%3600)/60; //error：变量搞错
66. tempBeijing->ui8Second = (totleSecNum%3600)%60;
68. //4.时区调整
69. tempBeijing->ui8Hour +=TIMEZONE;
70. if(tempBeijing->ui8Hour>23){
71. tempBeijing->ui8Hour -= 24;
72. tempBeijing->ui8DayOfMonth++;
73. }
74. }
76. // 将北京时间转换为Unix时间戳
77. // year: 需要判断的年
78. // return：Unix时间戳（从1970/1/1 00:00:00 到现在的秒数)
79. // note：没对输入参数正确性做判断
80. uint32_t covBeijing2UnixTimeStp(rtc_time_t *beijingTime)
81. {
82. uint32_t daynum=0, SecNum=0; //保存北京时间到起始时间的天数
83. uint16_t tempYear=1970, tempMonth=0;
86. //1.年的天数
87. while(tempYear < beijingTime->ui8Year)
88. {
89. if(isLeapYear(tempYear)){
90. daynum += 366;
91. }
92. else{
93. daynum += 365;
94. }
95. tempYear++;
96. }
97. //2.月的天数
98. while(tempMonth < beijingTime->ui8Month-1)
99. {
100. if(isLeapYear(beijingTime->ui8Year)){ //闰年
101. daynum += Leap_month_day[tempMonth];
102. }
103. else{
104. daynum += month_day[tempMonth];
105. }
106. tempMonth++;
107. }
108. //3.天数
109. daynum += (beijingTime->ui8DayOfMonth-1);
111. //4.时分秒
112. SecNum = daynum*24*60*60; //s
113. SecNum += beijingTime->ui8Hour*60*60;
114. SecNum += beijingTime->ui8Minute*60;
115. SecNum += beijingTime->ui8Second;
117. //5.时区调整
118. SecNum -= TIMEZONE*60*60;
120. return SecNum;
121. }

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3.timeconv.h

1. #ifndef __TIMECONV_H
2. #define __TIMECONV_H
3. ​
4. #include
5. #include
6. #include
7. #include "ohos_init.h"
8. #include "cmsis_os2.h"
9. #define FOURYEARDAY (((uint32_t)365+365+365+366))//4年一个周期内的总天数（1970~2038不存在2100这类年份，故暂不优化）
10. #define TIMEZONE (8) //北京时区调整
11. ​
12. typedef struct rtc_time_struct
13. {
14. uint16_t ui8Year; // 1970~2038
15. uint8_t ui8Month; // 1~12
16. uint8_t ui8DayOfMonth;// 1~31
17. uint8_t ui8Week;
18. uint8_t ui8Hour; // 0~23
19. uint8_t ui8Minute; // 0~59
20. uint8_t ui8Second; // 0~59
22. }rtc_time_t;
23. ​
24. uint8_t isLeapYear(uint16_t year);
25. void covUnixTimeStp2Beijing(uint32_t unixTime, rtc_time_t *tempBeijing);
26. uint32_t covBeijing2UnixTimeStp(rtc_time_t *beijingTime);
27. ​
28. #endif /*__TIMECONV_H*/
29. ​

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4、oled_demo.c

该c文件主要是oled显示屏显示程序、包括时间转换显示、温湿度显示。

1. extern float humidity;
2. extern float temperature;
3. static void OledTask(void *arg)
4. {
5. rtc_time_t mData;
6. (void)arg;
7. ​
8. GpioInit();
9. ​
10. OledInit();
11. OledFillScreen(0x00);
12. while (1) {
13. static char text[128] = {0};
14. unsigned short data = 0;
15. AdcRead(analog_KEY_CHAN_NAME, &data, WIFI_IOT_ADC_EQU_MODEL_4, WIFI_IOT_ADC_CUR_BAIS_DEFAULT, 0);
16. float voltage = ConvertToVoltage(data);
17. snprintf(text, sizeof(text), "voltage: %.3f!", voltage);
18. //OledShowString(0, 5, text, 1);
19. ​
20. OLED_ShowCHinese(0,3,0);//温
21. OLED_ShowCHinese(16,3,2);//度
22. OledShowChar(32,3,':',2);
23. sprintf((char *)TimeStr,"%02d",
24. (uint32_t)temperature);
25. OledShowString(40,3,(char *)TimeStr,2);
26. OLED_ShowCHinese(64,3,1);//湿
27. OLED_ShowCHinese(80,3,2);//度
28. OledShowChar(96,3,':',2);
29. sprintf((char *)TimeStr,"%02d",
30. (uint32_t)humidity);
31. OledShowString(104,3,(char *)TimeStr,2);
33. timedata++;
34. covUnixTimeStp2Beijing(timedata, &mData);
35. sprintf((char *)TimeStr,"%04d-%02d-%02d",
36. mData.ui8Year, mData.ui8Month, mData.ui8DayOfMonth);
37. OledShowString(24,0,(char *)TimeStr,1);
38. sprintf((char *)TimeStr,"%02d:%02d:%02d",
39. mData.ui8Hour,mData.ui8Minute,mData.ui8Second);
40. OledShowString(32,1,(char *)TimeStr,1);
41. sleep(1);
42. }
43. }

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5、oled_ssd1306.c

原来例程上是不能中文的，现在把显示中文功能加上，但是需要提前使用取模软件把字取模。

1. //显示汉字
2. void OLED_ShowCHinese(uint8_tx,uint8_ty,uint8_tno)
3. {
4. uint8_tt,adder=0;
5. OledSetPosition(x,y);
6. for(t=0;t<16;t++)
7. {
8. WriteData(Hzk[2*no][t]);
9. adder+=1;
10. }
11. OledSetPosition(x,y+1);
12. for(t=0;t<16;t++)
13. {
14. WriteData(Hzk[2*no+1][t]);
15. adder+=1;
16. }
17. }

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字模数组

1. static const unsigned charHzk[][16]={
2. {0x10,0x60,0x02,0x8C,0x00,0x00,0xFE,0x92,0x92,0x92,0x92,0x92,0xFE,0x00,0x00,0x00},
3. {0x04,0x04,0x7E,0x01,0x40,0x7E,0x42,0x42,0x7E,0x42,0x7E,0x42,0x42,0x7E,0x40,0x00},/*"温",0*/
4. /* (16 X 16 , 宋体 )*/
5. {0x10,0x60,0x02,0x8C,0x00,0xFE,0x92,0x92,0x92,0x92,0x92,0x92,0xFE,0x00,0x00,0x00},
6. {0x04,0x04,0x7E,0x01,0x44,0x48,0x50,0x7F,0x40,0x40,0x7F,0x50,0x48,0x44,0x40,0x00},/*"湿",1*/
7. /* (16 X 16 , 宋体 )*/
8. {0x00,0x00,0xFC,0x24,0x24,0x24,0xFC,0x25,0x26,0x24,0xFC,0x24,0x24,0x24,0x04,0x00},
9. {0x40,0x30,0x8F,0x80,0x84,0x4C,0x55,0x25,0x25,0x25,0x55,0x4C,0x80,0x80,0x80,0x00},/*"度",2*/
10. };

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6、BUILD.gn

BUILD.gn内容为

1. # Copyright (c) 2020, HiHope Community.
2. #
3. # Redistribution and use in source and binary forms, with or without
4. # modification, are permitted provided that the following conditions are met:
5. #
6. # 1. Redistributions of source code must retain the above copyright notice, this
7. # list of conditions and the following disclaimer.
8. #
9. # 2. Redistributions in binary form must reproduce the above copyright notice,
10. # this list of conditions and the following disclaimer in the documentation
11. # and/or other materials provided with the distribution.
12. #
13. # 3. Neither the name of the copyright holder nor the names of its
14. # contributors may be used to endorse or promote products derived from
15. # this software without specific prior written permission.
16. #
17. # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18. # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19. # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20. # DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
21. # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22. # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23. # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
24. # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
25. # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26. # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27. ​
28. static_library("oled_example") {
29. sources = [
30. "oled_demo.c",
31. "oled_ssd1306.c",
32. "timeconv.c",
33. "envrionment_demo.c",
34. "aht20.c"
35. ]
36. ​
37. include_dirs = [
38. "//utils/native/lite/include",
39. "//kernel/liteos_m/components/cmsis/2.0",
40. "//base/iot_hardware/inteRFaces/kits/wifiiot_lite",
41. ]
42. }

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这样还不行，还要修改app文件夹下的BUILD.gn。在features下增加"OLED:oled_example"，

1. lite_component("app") {
2. features = [
3. "startup",
4. "SSL:ssl_example",
5. "EM:em_example",
6. "OLED:oled_example"
7. ]
8. }

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三、 编译烧录

演示结果

四、总结

显示的时间是没有进行对时的，下一篇讲写关于如何连接网络，并且如何获取网络时间。然后把显示屏上时间更新为网络时间。

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