Linx Technologies HUM-xxx-DT - Manual (Page 19)

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Read Analog Voltage Value - Command Code = 26
This command reads the analog voltage on a specific GPIO line.
Parameter 1 is set to 0x00. Parameter 2 is the GPIO number to be queried,
where 0 corresponds to GPIO_0 and 7 is GPIO_7 and so forth.
The response returns four parameter bytes. Parameter 1 is set to 0x00
and Parameter 2 returns the GPIO number that is being read. Param 3
and Param 4 return the voltage value on the pin. The voltage on the pin is
calculated using the formula below.
Voltage (V) = [(Param 3) * 16 + (Param 4)] / 2047 * V
CC
For example, if a Read ADC Value command returns the following response
and V
CC
is 3.0V,
0x3C 0x26 0x00 0x07 0x21 0x0E 0x00 0x3E
This means that the voltage on GPIO_7 can be calculated as
[(0x21) * 16 + (0x0E)] / 2047 * 3.0 = 0.794V
The GPIO line being read must be configured as an analog input before the
ADC value can be read.
Parameter 5 indicates if the command was successful (00) or if there was
an error (01).
Read Analog Voltage Value Command and Response
Command
Start Command Param 1 Param 2 End
3C 26 00 GPIO 3E
Response
Start Response Param 1 Param 2 Param 3 Param 4 Param 5 End
3C 26 00 GPIO ADC1 ADC2 Status 3E
Figure 29: Read Analog Voltage Value Command and Response
Read Digital IO Value - Command Code = 27
This command reads the digital input value on a specific GPIO line.
This command returns four Parameter bytes. Parameter 1 is set to 0x00
and Parameter 2 returns the GPIO number that is being read.
Parameter 3 is the state of the GPIO line that is being read. If it is high,
Parameter 3 is 0x01. If it is low, Parameter 3 is 0x00.
Parameter 4 indicates if the command was successful (00) or if there was
an error (01).
The GPIO line being read must be configured as a digital input or output
before the value can be read.
Read Digital Input Value Command and Response
Command
Start Command Param 1 Param 2 End
3C 27 00 GPIO 3E
Response
Start Response Param 1 Param 2 Param 3 Param 4 End
3C 27 00 GPIO DIVal Status 3E
Figure 30: Read Digital Input Value Command and Response