1 FLEXIO overview
This application note describes how to use FlexIO module to emulate IrDA
protocol based on RT1010. Although RT1010 LPUART supports IrDA function,
FLEXIO emulation is an option when LPUART is not used.
FlexIO is an on-chip peripheral available on NXP i.MX RT series. It is a highly
configurable module capable of emulating a wide range of communication
protocols, such as UART, I2C, SPI, and I2S. Users can also use FlexIO to
generate PWM and PFM waveform.
For this application note, it is based on the function of the FLEXIO UART, using
a timer to implement the encoding and decoding of NRZ data.
2 IrDA overview
IrDA is a standardized wireless infrared data communication method. To
reduce the bit error rate, NRZ format data is used. At the same time, the transmitted data should be mixed with the carrier. Carrier
frequency is 38 kHz. The circuit in the Figure 2 shows how to mix the transmitted data and carrier. Infrared receiver is used to
receive mixed data and then the source data is used by MCU.
Figure 1. UART data and NRZ data
Contents
1 FLEXIO overview...................................1
2 IrDA overview........................................ 1
3 IrDA by FLEXIO..................................... 2
3.1 How to generate carrier
PWM by FLEXIO.....................3
3.2 How to configure an NRZ
encoder by FLEXIO.................3
3.3 How to configure an NRZ
decoder by FLEXIO ................4
3.4 Summary for NRZ data
encoding and decoding........... 5
4 How to develop it based on RT1010
EVK..................................................... 7
5 Revision history..................................... 8
AN12721
Emulating IRDA with the FlexIO on RT1010
Rev. 0 — 31 January 2020
Application Note
Figure 2. IrDA TX circuit
Figure 3. IrDA RX circuit
3 IrDA by FLEXIO
• How to generate carrier PWM by FLEXIO
• How to configure an NRZ encoder by FLEXIO
• How to configure an NRZ decoder by FLEXIO
• Summary for NRZ data encoding and decoding
NXP Semiconductors
IrDA by FLEXIO
Emulating IRDA with the FlexIO on RT1010, Rev. 0, 31 January 2020
Application Note 2 / 9