User manual

AHHYTM_E2.2.1
17/23
Application Note
Humidity Module
HYT
S 0x50 A 0x80 A 0x00 A 0x00 N P Start normaler mode
or alternatively Power – Off
The following table shows the I
2
C timing.
Command Byte Third and Fourth Bytes Description Response Time
§§
8 Command
Bits
16 Data Bits (Hex)
00
H
to 1F
H
0000
H
EEPROM Read of addresses 00
H
to 1F
H
After this command has been sent and
executed, a data fetch must be performed
100 µs
40
H
to 5F
H
YYYY
H
(Y = data) Write to EEPROM addresses 00
H
to 1F
H
The 2 bytes of data will be written to
the address specied in the 6 LSBs of the
command byte
12 ms
80
H
0000
H
Start_NOM
Ends Command Mode and transitions to
Normal Operation Mode
Length of initial
conversions depends
on temperature and
capacitance resolution
settings and the
capacitance „mult“
setting
A0
H
0000
H
Start_CM
Start Command Mode: used to enter the
command interpreting mode. Start_CM is
only valid during the power-on command
window
100 µs
B0
H
0000
H
Get revision
Get the revision of the part.
After this command has been sent and
executed, a data fetch must be performed
100 µs
5.1 Step by Step - I
2
C Address Change
1. Power-on-reset
2. Within 10 ms, send command 0XA0 (start command mode) through I
2
C bus. The default 7 bit I
2
C address is
0x28. In I
2
C write mode, the bit “W” shall be 0
0x50 0xA0 0x00 0x00 Send Start-Command-Mode
0x51 Response fetch, the bit “R” is 1
If the response is not 0x81, then you did not enter the command mode successfully
3. First try to read the conguration parameters stored inside EEPROM. If entering command-mode is successful,
the content can be read out successfully, otherwise start from step 1)
0x50 0X1C 0X00 0X00 Send read register 1C command. Register (1C) includes the I
2
C address
0x51 Read out data bytes with I
2
C address
4. If the response is not 0x81 0x00 0x28, then you did not read successfully
Change I
2
C address by sending the following command:
0x50 0x5C 0x00 0x31 Change I
2
C address into 0x31
Repeat 3) to conrm whether the I
2
C address is successfully changed. If successful, the response is 0x81 0x00
and 0x31
5. Power-off, if 1), 2), 3) and 4) failed