Data Sheet

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4. Peripheral Interface
The functionality of Infrared remote control interface can be implemented via software
programming. NEC coding, modulation, and demodulation are used by this interface. The
frequency of modulated carrier signal is 38 kHz, while the duty ratio of the square wave is
1/3. The transmission range is around 1m which is determined by two factors: one is the
maximum value of rated current, the other is internal current-limiting resistance value in the
infrared receiver. The larger the resistance value, the lower the current, so is the power, and
vice versa. The transmission angle is between 15° and 30° which is determined by the
radiation direction of the infrared receiver.
4.9. ADC (Analog-to-Digital Converter)
ESP8266EX is embedded with a 10-bit precision SARADC. TOUT (Pin6) is defined as
below.
The following two functions can be implemented using ADC (Pin 6). However, they cannot
be implemented at the same time.
• Test the power supply voltage of VDD3P3 (Pin 3 and Pin 4).
• Test the input voltage of TOUT (Pin 6).
Table 4-8. Pin Definitions of IR Remote Control
Pin Name
Pin Num
IO
Function Name
MTMS
9
IO14
IR Tx
GPIO5
24
IO 5
IR Rx
Table 4-9. Pin Definition of ADC
Pin Name
Pin Num
Function Name
TOUT
6
ADC Interface
Hardware Design
TOUT must be floating.
RF Initialization Parameter
The 107th byte of esp_init_data_default.bin (0 ~ 127 bytes), vdd33_const
must be set to 0xFF.
RF Calibration Process
Optimize the RF circuit conditions based on the testing results of VDD3P3 (Pin
3 and Pin 4).
User Programming
Use system_get_vdd33 instead of system_adc_read.
Hardware Design
The input voltage range is 0 to 1.0V when TOUT is connected to external
circuit.
RF Initialization Parameter
The value of the 107th byte of esp_init_data_default.bin (0 ~ 127 bytes),
vdd33_const must be set to the real power supply voltage of Pin 3 and Pin 4.
The working power voltage range of ESP8266EX is between 1.8V and 3.6V,
while the unit of vdd33_const is 0.1V, therefore, the effective value range of
vdd33_const is 18 to 36.
Espressif
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2017.04