Data Sheet

14
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HTE501
2. Periodic Measurement
G:\Produkte\HTEx01\501\Archive\PWRup_HIpin_Modi
Singelshotmode
Periodicmode
IDLEMODE PERIODICMODE IDLEMODE
time
time
COMMANDSingle
ShotMeasurement
Measurement
COMMANDSingle
ShotMeasurement
Measurement
SingleMeasurement
at
p
oweru
p
t
MEAS
V
DD
3.3V
V
PORP
0V
t
PWRU
t
MEAS
t
PWRU
SingleMeasurement
at
p
oweru
p
COMMAND
PeriodicMode
V
DD
3.3V
V
PORP
0V
COMMAND
Break
t
MEAS
t
MEAS
COMMAND
FetchMeasurement
Measurement
t
MEAS
COMMAND
FetchMeasurement
Timedependonmeasurement
intervall,1satstartup
Timedependonmeasurement
intervall,1satstartup
optionalCOMMAND
FetchMeasurement
optionalCOMMAND
FetchMeasurement
IDLEMODE
Timeuntil
nextCOMMAND
Timeuntil
nextCOMMAND
t
MEAS
t
MEAS
READMeasurement
READMeasurement
Measurement
COMMAND
FetchMeasurement
Measurement
Timedepend
onCOMMAND
19.10.2021
Figure 9: Periodic measurement
6.4 Single Shot Measurement (0x2C1B, 0x241D)
The command initiates a single measurement, the measured data is available for query after t
MEAS
.
I²C clock stretching enabled: waiting for the end of the measurement during command execution.
Condition CMD Hex Code
I
2
C clock stretching MSB LSB
Enabled 0x2C 0x1B
Disabled 0x24 0x1D
A single-shot measurement is started after the command has been received successfully. The readout of
the calculated values RH and T is started by sending the I
2
C address again in read mode:
I²C
Datenstruktur
7654321 76543210 76543210 7654321
S
W
0
A
0
A
0
A
0
PS
R
1
Without clock stretching
7654321
N
1
PS
R
1
A
0
With clock stretching
A
0
P
Next for both
76543210 76543210 76543210
A
0
A
0
A
0
76543210 76543210 76543210
A
0
A
0
N
1
P
!
R / W R / W
!
R / W
!
I2C-ADDRESS
CMD MSB
NEXT1
NEXT2
1
I2C-ADDRESS
I2C-ADDRESS
SCL FREE FOR OTHER BUS MEMBERS
MEASUREMENT ONGOING
t
MEAS
MEASUREMENT FINISHED
NEXT2
1
SCL PULLED LOW
TEMPERATURE MSB
2
TEMPERATURE LSB CRC8
NEXT3
HUMIDITY MSB
3
HUMIDITY LSB CRC8
16 BIT COMMAND
CMD LSB
MEASUREMENT ONGOING
t
MEAS
ASTRID_I2C_Befehle_version2 - Kopie / 0x2C06_0x241D 19.10.2021 \ Haider A.
Figure 10: Start single-shot measurement readout
In case a command with clock stretching enabled has been issued, the slave holds SCL low until the
calculation has been finished:
I²C
Datenstruktur
7654321 76543210 76543210 7654321
S
W
0
A
0
A
0
A
0
PS
R
1
Without clock stretching
7654321
N
1
PS
R
1
A
0
With clock stretching
A
0
P
Next for both
76543210 76543210 76543210
A
0
A
0
A
0
76543210 76543210 76543210
A
0
A
0
N
1
P
!
R / W R / W
!
R / W
!
I2C-ADDRESS
CMD MSB
NEXT1
NEXT2
1
I2C-ADDRESS
I2C-ADDRESS
SCL FREE FOR OTHER BUS MEMBERS
MEASUREMENT ONGOING
t
MEAS
MEASUREMENT FINISHED
NEXT2
1
SCL PULLED LOW
TEMPERATURE MSB
2
TEMPERATURE LSB CRC8
NEXT3
HUMIDITY MSB
3
HUMIDITY LSB CRC8
16 BIT COMMAND
CMD LSB
MEASUREMENT ONGOING
t
MEAS
ASTRID_I2C_Befehle_version2 - Kopie / 0x2C06_0x241D 19.10.2021 \ Haider A.
Figure 11: Clock stretching during measurement
E2Bus
Datenstruktur
Zeichenerklärung
Data Bit From Master to Slave
Data Bit From Slave to Master
S = Start condition R = Read Bit
P = Stop condition W = Write Bit
A = Acknowledge (SDA low)
N = Not Acknowledge (SDA high)
!
= Note the deviation!
ASTRID_I2C_Befehle_version2 - Kopie / Zeichenerklärung 19.10.2021 \ Kofler