一、分析AHT10 技术手册

（一）Temperature and humidity sensor information（不太重要）

1.简介

2.应用范围

3.传感器性能

（二）Temperature and humidity sensor information（重要）

1.接口

2.串行时钟线SCL

3.串行数据线SDA

4.I2C时序

5.AHT10指令

6.状态位说明

7.Read the temperature and humidity process

（1）Trigger on measurement data

（2）读取温湿度

8.采集数据处理

二、思路

（类似于I2C读写EEPROM,So the whole frame diagram is very similar）

（Power on first and wait40ms,Then enter the idle state,Then a read operation is performed,Depending on the status bytes are returnedbit[3]to determine whether initialization is required.如果bit[3]=0则需要进行初始化（Send a write control byte,0xE1命令,初始化参数0x08,0x00）如果是bit[3]=1则不需要初始化,Triggered measurements can be started directly（发送控制字节,0xAC命令,触发参数0x33,0x00）,Wait after the measurement is complete80ms（The read operation should have been performed again,Judging the status bytebit[7]Check whether the measurement has been completed and the device is idle.But it feels cumbersome,延迟80ms应该够了,Therefore, this read status operation is not performed）,Then read the temperature and humidity operation（Send a read control byte））

（一）The frame diagram of the temperature and humidity acquisition system

模块说明：

1.顶层模块–aht10

aht10(
    input      clk    ,
    input      rst_n  ,
 
    output     i2c_scl,
    inout      i2c_sda,           
    output     tx 
);

2.控制模块–controller

controller(
  input clk    ,
  input rst_n  ,

  input busy   ,
  
  output i2c_scl   ,
  inout  i2c_sda   ,
  output [7:0] data_tx,
  output       data_tx_vld
);

​ 控制aht10_rw和i2c_interface数据传输,接收uart_tx模块的busy信号,输出data_tx和data_tx_vld给uart_tx模块,传输i2c时钟和数据.

3.AHT10读写模块–aht10_rw

aht10_rw(
input            clk      ,
input            rst_n    ,
    
input            busy     ,
    
output           req      ,
output [3:0]     cmd      ,
output [7:0]     wr_data  ,

input  [7:0]     rd_data  ,
output reg [7:0] dout     ,
output reg       dout_vld ,
input            done     ,
input            slave_ack
);

​ According to the status pairi2cThe interface module sends the request、命令（读、写、起始、停止）、发送数据.实现控制i2cInterface module pairaht10The sensor performs read and write operations.Handles receiving data and sending ituart_tx模块.

数据处理

（I worked with the data directly in this module）

思路：

（1）Store data in bytes[19:0]RH和[19:0]TP中,Filter out status bytes,Place the back of the THM byte before2.5字节存入[19:0]RH,后2.5字节存入[19:0]TP.

//数据处理
//RH、TP
[email protected](posedge clk or negedge rst_n)begin
  if(!rst_n)begin
     RH <= 1'b0;
     TP <= 1'b0;
  end
  else if(state_c == READ_WAIT && cnt_byte == 2) begin
     RH[19:12] <= rd_data;
     TP <= 1'b0; 
  end
  else if(state_c == READ_WAIT && cnt_byte == 3) begin
     RH[11:4] <= rd_data; 
     TP <= 1'b0;
  end
  else if(state_c == READ_WAIT && cnt_byte == 4) begin
     RH[3:0] <= rd_data[7:4]; 
     TP[19:16] <= rd_data[3:0];
  end
  else if(state_c == READ_WAIT && cnt_byte == 5) begin
     RH <= RH;
     TP[15:8] <= rd_data;
  end
  else if(state_c == READ_WAIT && cnt_byte == 6) begin
    RH <= RH;
    TP[7:0] <= rd_data;
  end
end

（2）Process data by formula

wire [39:0] RH_r;
wire [39:0] TP_r;

assign RH_r = (RH * 10000)>>20;
assign TP_r = ((TP * 20000)>>20) - 5000;

（3）将数据转换为ASCII码

wire [7:0] data_r [15:0];//Register humidity、Tens of thousands of temperature
assign data_r [0]  = 8'b01010010                    ;//R
assign data_r [1]  = 8'b01001000                    ;//H
assign data_r [2]  = 8'b00111010                    ;//:
assign data_r [3]  = RH_r /1000 + 8'b0011_0000;//Humidity in thousands
assign data_r [4]  = RH_r /100 %10 + 8'b0011_0000;//Humidity in the hundreds
assign data_r [5]  = 8'b00101110                    ;//.
assign data_r [6]  = RH_r /10 %10 + 8'b0011_0000;//Tens of humidity
assign data_r [7]  = RH_r %10 + 8'b0011_0000;//Humidity bits
assign data_r [8]  = 8'b01010100                    ;//T
assign data_r [9]  = 8'b01010000                    ;//P
assign data_r [10] = 8'b00111010                    ;//:
assign data_r [11] = TP_r /1000 + 8'b0011_0000;//Temperature in thousands
assign data_r [12] = TP_r /100 %10 + 8'b0011_0000;//温度百位
assign data_r [13] = 8'b00101110                    ;//.
assign data_r [14] = TP_r /10 %10 + 8'b0011_0000;//温度十位
assign data_r [15] = TP_r %10 + 8'b0011_0000;//温度个位

4.I2C接口模块–i2c_interface

i2c_interface(
 input             clk       ,
 input             rst_n     , 
 //主机发送数据            
 input             req       ,//请求
 input      [3:0]  cmd       ,//i2c接口指令,控制状态
 input      [7:0]  din       ,//i2cThe data that the interface needs to send 
 //主机接收数据
 output     [7:0]  dout      ,//i2c接口接收的数据
 output            done      ,//完成一次读/写指令
 output            slave_ack ,//The response from the master to the slave 
 //从机接收数据
 output            i2c_scl    ,//i2c时钟
 input             i2c_sda_i  , //i2cSend data to the host
 output            i2c_sda_o  ,//The master sends data to the slave
 output            i2c_sda_oe      
);

​ 根据aht10_rw模块的请求、command for read and write operations,满足i2c读写时序,产生i2c时钟,控制i2cThe clock line and the data line are used for data transmission.

（二）状态转移图

1.AHT10_RWModule state transition diagram

（1）状态说明：

WAIT:上电等待40ms

IDLE:空闲状态

STATU、STATU_WAIT:Read the status byte status and its wait states

INIT、INIT_WAIT:The initialization state and its wait states

START、START_WAIT:Trigger state and its wait state

READ、READ_WAIT:Read the temperature and humidity data status and its waiting status

DONE:结束状态

（2）The number of individual status bytes：

读状态 读控制字节（8’b0111_0001） Read the status byte 共两字节

初始化 写控制字节（8’b0111_0000） 写命令（8’b11100001） 写两个参数（8’b00001000、8’b00000000） 共四字节

触发测量 写控制字节（8’b0111_0000） 写命令（8’b10101100） 写两个参数（8’b00110011、8’b00000000） 共四字节

读数据 读控制字节（8’b0111_0001） read six bytes 共七字节

（3）状态转移条件：

2.I2C_interfaceModule state transition diagram

状态跳转条件：

三、实验结果

（一）实验效果

（二）仿真

1、State jump simulation

(1)读状态、初始化状态

（2）读状态、Trigger measurement state

（3）Read the temperature and humidity status

2、Data processing simulation

3.RTL视图