1 /*
2 * Copyright (C) 2022 HiHope Open Source Organization .
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http:// www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 *
14 * limitations under the License.
15 */
16
17 #include "aht20.h"
18
19 #include <stdio.h>
20 #include <string.h>
21 #include <unistd.h>
22
23 #include "wifiiot_i2c.h"
24 #include "wifiiot_errno.h"
25
26 #define AHT20_I2C_IDX WIFI_IOT_I2C_IDX_0
27
28 #define AHT20_STARTUP_TIME (20*1000) // 上电启动时间
29 #define AHT20_CALIBRATION_TIME (40*1000) // 初始化（校准）时间
30 #define AHT20_MEASURE_TIME (75*1000) // 测量时间
31
32 #define AHT20_DEVICE_ADDR 0x38
33 #define AHT20_READ_ADDR ((0x38<<1)|0x1)
34 #define AHT20_WRITE_ADDR ((0x38<<1)|0x0)
35
36 #define AHT20_CMD_CALIBRATION 0xBE // 初始化（校准）命令
37 #define AHT20_CMD_CALIBRATION_ARG0 0x08
38 #define AHT20_CMD_CALIBRATION_ARG1 0x00
39
40 #define NUM 8
41 #define NUM_TWO 2
42 #define NUM_THREE 3
43 #define NUM_FOUR 4
44 #define NUM_FIVE 5
45 #define NUM_FIFTY 50
46 #define ONE_HUNDRED 100
47 #define TWO_HUNDRED 200
48
49 /**
50 * 传感器在采集时需要时间,主机发出测量指令（0xAC）后，延时75毫秒以上再读取转换后的数据并判断返回的状态位是否正常。
51 * 若状态比特位[Bit7]为0代表数据可正常读取，为1时传感器为忙状态，主机需要等待数据处理完成。
52 **/
53 #define AHT20_CMD_TRIGGER 0xAC // 触发测量命令
54 #define AHT20_CMD_TRIGGER_ARG0 0x33
55 #define AHT20_CMD_TRIGGER_ARG1 0x00
56
57 // 用于在无需关闭和再次打开电源的情况下，重新启动传感器系统，软复位所需时间不超过20 毫秒
58 #define AHT20_CMD_RESET 0xBA // 软复位命令
59
60 #define AHT20_CMD_STATUS 0x71 // 获取状态命令
61
62 /**
63 * STATUS 命令回复：
64 * 1. 初始化后触发测量之前，STATUS 只回复 1B 状态值；
65 * 2. 触发测量之后，STATUS 回复6B： 1B 状态值 + 2B 湿度 + 4b湿度 + 4b温度 + 2B 温度
66 * RH = Srh / 2^20 * 100%
67 * T = St / 2^20 * 200 - 50
68 **/
69 #define AHT20_STATUS_BUSY_SHIFT 7 // bit[7] Busy indication
70 #define AHT20_STATUS_BUSY_MASK (0x1<<AHT20_STATUS_BUSY_SHIFT)
71
aht20_status_busy(uint8_t status)72 uint8_t aht20_status_busy(uint8_t status)
73 {
74 return ((status & AHT20_STATUS_BUSY_MASK) >> (AHT20_STATUS_BUSY_SHIFT));
75 }
76
77 #define AHT20_STATUS_MODE_SHIFT 5 // bit[6:5] Mode Status
78 #define AHT20_STATUS_MODE_MASK (0x3<<AHT20_STATUS_MODE_SHIFT)
79
aht20_status_mode(uint8_t status)80 uint8_t aht20_status_mode(uint8_t status)
81 {
82 return ((status & AHT20_STATUS_MODE_MASK) >> (AHT20_STATUS_MODE_SHIFT))
83 }
84
85 #define AHT20_STATUS_CALI_SHIFT 3 // bit[3] CAL Enable
86 #define AHT20_STATUS_CALI_MASK (0x1<<AHT20_STATUS_CALI_SHIFT)
87
88 uint8_t aht20_status_cali(uint8_t status)
89 {
90 return ((status & AHT20_STATUS_CALI_MASK) >> (AHT20_STATUS_CALI_SHIFT))
91 }
92
93
94 #define AHT20_STATUS_RESPONSE_MAX 6
95
96 #define AHT20_RESOLUTION (1<<20) // 2^20
97
98 #define AHT20_MAX_RETRY 10
99
100 static uint32_t AHT20_Read(uint8_t* buffer, uint32_t buffLen)
101 {
102 WifiIotI2cData data = { 0 };
103 data.receiveBuf = buffer;
104 data.receiveLen = buffLen;
105 uint32_t retval = I2cRead(AHT20_I2C_IDX, AHT20_READ_ADDR, &data);
106 if (retval != WIFI_IOT_SUCCESS) {
107 printf("I2cRead() failed, %0X!\n", retval);
108 return retval;
109 }
110 return WIFI_IOT_SUCCESS;
111 }
112
113 static uint32_t AHT20_Write(uint8_t* buffer, uint32_t buffLen)
114 {
115 WifiIotI2cData data = { 0 };
116 data.sendBuf = buffer;
117 data.sendLen = buffLen;
118 uint32_t retval = I2cWrite(AHT20_I2C_IDX, AHT20_WRITE_ADDR, &data);
119 if (retval != WIFI_IOT_SUCCESS) {
120 printf("I2cWrite(%02X) failed, %0X!\n", buffer[0], retval);
121 return retval;
122 }
123 return WIFI_IOT_SUCCESS;
124 }
125
126 // 发送获取状态命令
127 static uint32_t AHT20_StatusCommand(void)
128 {
129 uint8_t statusCmd[] = { AHT20_CMD_STATUS };
130 return AHT20_Write(statusCmd, sizeof(statusCmd));
131 }
132
133 // 发送软复位命令
134 static uint32_t AHT20_ResetCommand(void)
135 {
136 uint8_t resetCmd[] = {AHT20_CMD_RESET};
137 return AHT20_Write(resetCmd, sizeof(resetCmd));
138 }
139
140 // 发送初始化校准命令
141 static uint32_t AHT20_CalibrateCommand(void)
142 {
143 uint8_t clibrateCmd[] = {AHT20_CMD_CALIBRATION, AHT20_CMD_CALIBRATION_ARG0, AHT20_CMD_CALIBRATION_ARG1};
144 return AHT20_Write(clibrateCmd, sizeof(clibrateCmd));
145 }
146
147 // 读取温湿度值之前， 首先要看状态字的校准使能位Bit[3]是否为 1(通过发送0x71可以获取一个字节的状态字)，
148 // 如果不为1，要发送0xBE命令(初始化)，此命令参数有两个字节， 第一个字节为0x08，第二个字节为0x00。
149 uint32_t AHT20_Calibrate(void)
150 {
151 uint32_t retval = 0;
152 uint8_t buffer[AHT20_STATUS_RESPONSE_MAX];
153 reval = memset_s(&buffer, sizeof(buffer), 0x0, sizeof(buffer));
154 if (reval == TRUE) {
155 printf("OK");
156 }
157
158 retval = AHT20_StatusCommand();
159 if (retval != WIFI_IOT_SUCCESS) {
160 return retval;
161 }
162
163 retval = AHT20_Read(buffer, sizeof(buffer));
164 if (retval != WIFI_IOT_SUCCESS) {
165 return retval;
166 }
167
168 if (AHT20_STATUS_BUSY(buffer[0]) || !AHT20_STATUS_CALI(buffer[0])) {
169 retval = AHT20_ResetCommand();
170 if (retval != WIFI_IOT_SUCCESS) {
171 return retval;
172 }
173 usleep(AHT20_STARTUP_TIME);
174 retval = AHT20_CalibrateCommand();
175 usleep(AHT20_CALIBRATION_TIME);
176 return retval;
177 }
178
179 return WIFI_IOT_SUCCESS;
180 }
181
182 // 发送 触发测量 命令，开始测量
183 uint32_t AHT20_StartMeasure(void)
184 {
185 uint8_t triggerCmd[] = {AHT20_CMD_TRIGGER, AHT20_CMD_TRIGGER_ARG0, AHT20_CMD_TRIGGER_ARG1};
186 return AHT20_Write(triggerCmd, sizeof(triggerCmd));
187 }
188
189 // 接收测量结果，拼接转换为标准值
190 uint32_t AHT20_GetMeasureResult(float* temp, float* humi)
191 {
192 uint32_t retval = 0, i = 0;
193 if (temp == NULL || humi == NULL) {
194 return WIFI_IOT_FAILURE;
195 }
196
197 uint8_t buffer[AHT20_STATUS_RESPONSE_MAX];
198 reval = memset_s(&buffer, sizeof(buffer), 0x0, sizeof(buffer));
199 if (reval == TRUE) {
200 printf("OK");
201 }
202
203 retval = AHT20_Read(buffer, sizeof(buffer)); // recv status command result
204 if (retval != WIFI_IOT_SUCCESS) {
205 return retval;
206 }
207
208 for (i = 0; AHT20_STATUS_BUSY(buffer[0]) && i < AHT20_MAX_RETRY; i++) {
209 usleep(AHT20_MEASURE_TIME);
210 retval = AHT20_Read(buffer, sizeof(buffer)); // recv status command result
211 if (retval != WIFI_IOT_SUCCESS) {
212 return retval;
213 }
214 }
215 if (i >= AHT20_MAX_RETRY) {
216 printf("AHT20 device always busy!\r\n");
217 return WIFI_IOT_FAILURE;
218 }
219
220 uint32_t humiRaw = buffer[1];
221 humiRaw = (humiRaw << NUM) | buffer[NUM_TWO];
222 humiRaw = (humiRaw << NUM_FOUR) | ((buffer[NUM_THREE] & 0xF0) >> NUM_FOUR);
223 *humi = humiRaw / (float)AHT20_RESOLUTION * ONE_HUNDRED;
224
225 uint32_t tempRaw = buffer[3] & 0x0F;
226 tempRaw = (tempRaw << NUM) | buffer[NUM_FOUR];
227 tempRaw = (tempRaw << NUM) | buffer[NUM_FIVE];
228 *temp = tempRaw / (float)AHT20_RESOLUTION * TWO_HUNDRED - NUM_FIFTY;
229 return WIFI_IOT_SUCCESS;
230 }
231