Infrared Interface (IR)

Supported ICs[ RTL8721Dx ][ RTL8730E ][ RTL8721F ][...]

Introduction

The IR module is used to process infrared signals with carrier frequencies below 500 kHz, supporting both transmit (Tx) and receive (Rx) operating modes in a half-duplex manner.

In the transmit direction, the IR IP features built-in hardware modulation that directly performs carrier modulation and drives the IR Tx output. In the receive direction, the IR IP can measure the pulse width periods of consecutive high and low level signals, and writes the measurement results into the Rx FIFO sequentially for software to parse the infrared waveform sequence and perform further processing. Additionally, the receive front-end supports two hardware configurations: IR Diode and IR Receiver Module, enabling users to choose flexibly based on actual application scenarios.

Features

• Supports customizable transmit carrier frequency, configurable range: 25kHz to 500kHz

• Supports customizable transmit carrier duty cycle

• Receive front-end supports two hardware input types: IR diode and IR receiver module

• 32 x 4-byte Tx FIFO

• 32 x 4-byte Rx FIFO

• Supports half-duplex operation mode

Block Diagram

The IR module block diagram is shown below:

• Scaler: Divides the clock based on SCLK to generate the Tx carrier frequency or Rx sampling frequency.

• Carrier Generator: Generates Tx carrier symbols and supports flexible duty cycle configuration.

• Modulation: Modulates space symbols into carrier symbols.

• Glitch Filter: Filters out glitch interference from bus signals at the receiving end.

• FIFO

  • Tx FIFO: Stores Tx carrier symbol count values and data states.

  • Rx FIFO: Buffers data received from the bus for software to read and process.

• Interrupt Control: Generates interrupt events to the processor.

• Register: Used to configure IR module parameters.

Working Principle

To simplify the IR signal model, an IR signal is divided into several symbols. Symbols are classified into two types: a signal that contains several carrier clock cycles within a specific period is called a Carrier Symbol; a signal that maintains a continuous high or low level within a specific period is called a Space Symbol. The carrier symbol corresponds to the actual signal transmitted in the air, while the space symbol corresponds to the baseband signal before modulation or after demodulation.

Transmit Mode

In Tx mode, software first configures modulation parameters to generate a fixed-frequency carrier, then writes space symbols into the Tx FIFO. The Tx module automatically performs modulation and transmits the IR signal. The IR Tx flow is shown in the following figure.

Receive Mode

In Rx mode, the IR IP uses the sampling clock as a reference to measure the pulse width of continuous high and low level signals in the input, and writes the measurement results sequentially into the Rx FIFO for software to parse the waveform. The IR IP supports two types of Rx front end:

• IR receiver module: The carrier has already been filtered by the front-end module, and the input signal is a clean baseband signal. The IR IP directly captures space symbols, and software only needs to decode them.

• IR diode: The input signal still carries the carrier. The IR IP captures carrier symbols, and software needs to demodulate before decoding, which incurs additional CPU overhead.

The IR Rx flow is shown in the following figure.

Functional Description

Scaler

The scaler is the core clock processing unit of the IR module. It takes the system clock (SCLK) as input and generates the required internal clocks for the IR module through programmable division. By configuring the IR_CLK_DIV bit field (12 bits) of the IR_CLK_DIV register, the division factor can be flexibly set: divided clock frequency = SCLK / (IR_CLK_DIV + 1).

• Tx Mode

  In Tx mode, the scaler output clock is the carrier frequency. The Carrier Generator uses this clock to produce carrier symbols with adjustable duty cycle for driving IR transmission.

  For example, when SCLK = 100 MHz and the target carrier frequency is 455 kHz, IR_CLK_DIV = (100M / 455k) - 1.

• Rx Mode

  In Rx mode, the scaler output clock is the sampling clock. The Rx counter uses the sampling clock as a reference to count the duration of high and low levels in the input signal, and writes the measurement results into the Rx FIFO for software to parse the waveform.

  For example, when the Rx sampling clock is 10 MHz and the Rx count value is 0x800000FF, it indicates a high level duration of 255 μs (where bit[31] indicates the input level: 1 = high level, 0 = low level).

The IR IP input clock (SCLK) frequency varies by chip:

RTL8721DxRTL8730ERTL8721F

RTL8721Dx:

The default clock frequency is 40 MHz.

Transmit Mode

FIFO Format

To transmit IR data, data must be written to the IR Tx FIFO register, so understanding its data format is essential. Before transmission, data should be converted to the format defined by the Tx FIFO register. The Tx FIFO register is 32 bits wide, with the following bit definitions:

Bit[31]:

Data level flag. 1 = high level, 0 = low level.

Bit[30]:

Data end flag. 1 = last packet of the current transmission, 0 = normal packet.

Bit[29:28]:

Tx compensation mode. 00 = use Tsample, 11 = use Tcomp_clk.

Bit[27:0]:

Number of carrier cycles.

Let f_carrierrepresent the carrier frequency (in Hz), and T_durationrepresent the duration of a carrier symbol or space symbol (in μs). Then:

bit[27:0] = f_carrier× T_duration

FIFO Filling

Taking the NEC protocol as an example, the carrier frequency is 38 kHz. The NEC format is shown in the figure below, consisting of 2 start symbols, 64 data symbols, and 1 stop symbol.

• To transmit logic ‘1’, two words must be written to the Tx FIFO register:

  • First word: bit[31] = 1, bit[30] = 0, bit[27:0] = 38 × 560 / 1000 = 21.

  • Second word: bit[31] = 0, bit[30] = 0, bit[27:0] = 38 × (2250 - 560) / 1000 = 64.

• To transmit logic ‘0’, two words must be written to the Tx FIFO register:

  • First word: bit[31] = 1, bit[30] = 0, bit[27:0] = 38 × 560 / 1000 = 21.

  • Second word: bit[31] = 0, bit[30] = 0, bit[27:0] = 38 × (1120 - 560) / 1000 = 21.

Finally, a stop symbol must be sent, with bit[30] = 1 to indicate the end of the current transmission.

Compensation Mechanism

In most application scenarios, the compensation mechanism does not need to be enabled. If precision is not a concern, this section can be skipped.

The Tx waveform consists of several carrier symbols and space symbols. Software calculates the duration of each symbol based on protocol specifications (e.g., NEC), but the duration of space symbols typically cannot be exactly divided by the carrier period. Without compensation, the error accumulates across symbols. To address this, IR Tx introduces a compensation mechanism to reduce the error.

Taking the NEC application as an example, the following figure shows the Tx NEC waveform with f_carrier= 38 kHz, duty = 1/3, and system clock of 100 MHz.

For 38 kHz carrier frequency:

T_carrier= 1 / f_carrier= 1 / 38 k = 26.31μs

T_{carrier_duty}= T_carrier× duty = 8.77μs

The compensation frequency f_compis an independent clock source that can be set to any desired frequency. In this example, f_comp= 1 MHz, so:

T_comp= 1 / f_comp= 1μs

Tx NEC waveform

The waveform is divided into four symbols: 560μs carrier symbol, 1690μs space symbol (2250μs - 560μs), 560μs carrier symbol, and 560μs space symbol (1120μs - 560μs). Comparing the two calculation methods below shows that the accuracy is significantly improved when using the compensation mechanism.

Item	Normal Tx (IR_TX_COMPENSATION = 0)	Tx Compensation (IR_TX_COMPENSATION = 3)
1st cycle	560μs ≈ 21 × 26.31 + 8.77 = 561.26μs	560μs ≈ 21 × 26.31 + 8.77 = 561.26μs
2nd cycle	1690μs ≈ 64 × 26.31 + (26.31 - 8.77) = 1701.38μs	1690μs ≈ (26.31 - 8.77) + 1673 × 1 = 1690.54μs
3rd cycle	560μs ≈ 21 × 26.31 + 8.77 = 561.26μs	560μs ≈ 21 × 26.31 + 8.77 = 561.26μs
4th cycle	560μs ≈ 21 × 26.31 + (26.31 - 8.77) = 570.05μs	560μs ≈ (26.31 - 8.77) + 543 × 1 = 560.54μs
Tx FIFO Data Value	0x80000015, 0x00000040; 0x80000015, 0x00000015	0x80000015, 0x30000689; 0x80000015, 0x3000021F

Note

• The compensation mechanism only applies to space symbols.

• Compensation modes IR_TX_COMPENSATION = 1 and IR_TX_COMPENSATION = 2 are not recommended. If compensation is needed, use IR_TX_COMPENSATION = 3 mode.

• If IR_TX_DE_INVERSE is enabled, ensure that the Tx compensation divider IR_TX_COMPE_DIV IR_TX_COMPE_DIV (register 0xC[11:0]) is no less than the Tx duty count value IR_TX_CONFIG IR_TX_DUTY_NUM (register 0x4[27:16]).

Receive Mode

FIFO Format

When receiving IR data, data must be read from the Rx FIFO register, so understanding its data format is crucial. The Rx FIFO register is 32 bits wide, with bit definitions as follows:

• Bit[31] indicates the data level. 1 = high level, 0 = low level.

• Bit[30:0] stores the received data, representing the level duration in number of sampling periods.

Let f_samplingdenote the sampling frequency (in kHz), and T_leveldenote the duration of the corresponding high/low level (in μs). Then:

T_level= bit[30:0] / f_sampling× 1000

Software can further parse the IR protocol and extract the required information based on T_level.

Receive Start

Both automatic start and manual start are supported, controlled by IR_RX_START_MODE (register 0x18[27]) of IR_RX_CONFIG.

Automatic Start

Set IR_RX_START_MODE = 1 to enter automatic receive mode. In this mode, when the Rx input signal meets the preset trigger condition, the hardware automatically starts receiving. The trigger type is configured through IR_RX_TRIGGER_MODE:

Value	Trigger Type	Description
00	IR_RX_FALL_EDGE	Triggered when a falling edge (high level to low level) is detected
01	IR_RX_RISING_EDGE	Triggered when a rising edge (low level to high level) is detected
10	IR_RX_DOUBLE_EDGE	Triggered when any level transition (rising edge or falling edge) is detected

After enabling the Rx module, the hardware automatically waits for the trigger condition without software intervention.

Manual Start

Set IR_RX_START_MODE = 0 to enter manual receive mode. In this mode, software starts receiving by writing 1 to IR_RX_MAN_START (register 0x18[28]) of IR_RX_CONFIG, suitable for scenarios requiring precise control over the receive start point.

Receive Termination

The Rx module determines receive termination through a counter threshold interrupt. When the duration of a certain level in the input signal exceeds the preset threshold, the IR_RX_CNT_THR_INT_STATUS interrupt is triggered, indicating the end of a complete IR reception.

The termination condition is jointly determined by the following register settings:

• Termination level type ( IR_RX_CNT_THR_TRIGGER_LV ):

  • 0: Trigger interrupt when low level duration >= threshold

  • 1: Trigger interrupt when high level duration >= threshold

• Count threshold ( IR_RX_CNT_THR ): 31-bit threshold, duration = threshold / sampling frequency.

• Interrupt enable: IR_RX_CNT_THR_INT_EN must be enabled to receive interrupt notification when the condition is met.

Note

The threshold should be configured according to the characteristics of the IR signal in the application scenario. The interval between two IR data frames is typically longer than the duration of any single level within a transmission, so setting this interval as the threshold can reliably distinguish data frames.

Receive Filter

The IR Rx input has a built-in glitch filter that can filter out narrow pulse interference before sampling. The filter width is configured through IR_RX_FILTER_STAGETX (register 0x18[23:21]) of IR_RX_CONFIG. The filter width mappings for each chip are as follows:

RTL8721DxRTL8730ERTL8721F

RTL8721Dx:

Available filter widths: 50 ns, 75 ns, 100 ns, 125 ns, 150 ns, 175 ns, 200 ns, 225 ns.

Interrupt

The interrupt flags supported in each mode are listed below. Each interrupt source can be individually enabled, masked, or cleared.

Mode	Interrupt Flag	Description
Tx Mode	IR_TX_FIFO_OVER_INT	This interrupt is triggered when data is written to Tx FIFO while it is already full.
	IR_TX_FIFO_LEVEL_INT	This interrupt is triggered when Tx FIFO usage drops from the threshold to threshold - 1.
	IR_TX_FIFO_EMPTY_INT	This interrupt is triggered when Tx FIFO usage drops from 1 to 0 (i.e., FIFO is empty).
Rx Mode	IR_RX_FIFO_ERROR_INT	This interrupt is triggered when data is read from Rx FIFO while it is empty.
	IR_RX_CNT_THR_INT	This interrupt is triggered when the input level duration exceeds the Rx counter threshold.
	IR_RX_CNT_OF_INT	This interrupt is triggered when the Rx counter overflows without triggering IR_RX_CNT_THR_INT.
	IR_RX_FIFO_OF_INT	This interrupt is triggered when new data is received from the IR input pin while Rx FIFO is already full.
	IR_RX_FIFO_LEVEL_INT	This interrupt is triggered when Rx FIFO usage rises from the threshold to threshold + 1.
	IR_RX_FIFO_FULL_INT	This interrupt is triggered when Rx FIFO becomes full.

Registers

RTL8721DxRTL8730ERTL8721F

RTL8721Dx:

Base Address: 0x41107000

Name	Address offset	Access	Description
REG_IR_CLK_DIV	000h	R/W
REG_IR_TX_CONFIG	004h	R/W
REG_IR_TX_SR	008h	R
REG_IR_TX_COMPE_DIV	00Ch	R/W
REG_IR_TX_INT_CLR	010h	R/W
REG_IR_TX_FIFO	014h	R/W
REG_IR_RX_CONFIG	018h	R/W
REG_IR_RX_SR	01Ch	R
REG_IR_RX_INT_CLR	020h	R/W
REG_IR_RX_CNT_INT_SEL	024h	R/W
REG_IR_RX_FIFO	028h	R
REG_IR_VERSION	02Ch	R
REG_IR_DUMMY	030h	R

REG_IR_CLK_DIV

• Name: IR clock division register

• Size: 32

• Address offset: 000h

• Read/write access: R/W

Bit	Symbol	Access	INI	Description
31:12	RSVD	R	-	Reserved
11:0	IR_CLK_DIV	R/W	0x0	IR_CLK = IO_CLK/(1 + IR_CLK_DIV) Tx mode: divider number to generate IrDA modulation frequency. For example: sys_clk = 100MHz, modulation_freq = 455kHz, IR_DIV_NUM = (sys_clk/modulation_freq) - 1 Rx mode: waveform sample clock. IR_DIV_NUM = (sys_clk/sample clock) - 1 For example: sample clock = 100MHz, IR_DIV_NUM = 0; sample clock = 50MHz, IR_DIV_NUM = 1

REG_IR_TX_CONFIG

• Name: IR Tx configuration register

• Size: 32

• Address offset: 004h

• Read/write access: R/W

Bit	Symbol	Access	INI	Description
31	IR_MODE_SEL	R/W	0x0	0: Tx mode 1: Rx mode
30	IR_TX_START	R/W	0x0	0: FSM stops at idle state. 1: FSM runs.
29:28	RSVD	R	-	Reserved
27:16	IR_TX_DUTY_NUM	R/W	0x0	Duty cycle setting for modulation frequency For example: for 1/3 duty cycle, IR_DUTY_NUM = (IR_DIV_NUM+1)/3 Note Set this value equal to IR_DIV_NUM to generate 100% duty waveform.
15	RSVD	R	-	Reserved
14	IR_TX_OUTPUT_INVERSE	R/W	0x0	0: Not inverse active output 1: Inverse active output
13	IR_TX_DE_INVERSE	R/W	0x0	0: Not inverse FIFO define 1: Inverse FIFO define
12:8	IR_TX_FIFO_LEVEL_TH	R/W	0x0	Tx FIFO interrupt threshold. When Tx FIFO depth = < threshold value, interrupt is triggered.
7	RSVD	R	-	Reserved
6	IR_TX_IDLE_STATE	R/W	0x0	Tx output state in idle 0: Low 1: High
5	IR_TX_FIFO_OVER_INT_MASK	R/W	0x0	Tx FIFO overflow interrupt 0: Unmask 1: Mask
4	IR_TX_FIFO_OVER_INT_EN	R/W	0x0	Tx FIFO overflow interrupt 0: Disable 1: Enable
3	IR_TX_FIFO_LEVEL_INT_MASK	R/W	0x0	Tx FIFO level interrupt 0: Unmask 1: Mask
2	IR_TX_FIFO_EMPTY_INT_MASK	R/W	0x0	Tx FIFO empty interrupt 0: Unmask 1: Mask
1	IR_TX_FIFO_LEVEL_INT_EN	R/W	0x0	Tx FIFO level interrupt When Tx FIFO offset <= threshold value, interrupt is triggered. 0: Disable 1: Enable
0	IR_TX_FIFO_EMPTY_INT_EN	R/W	0x0	Tx FIFO empty interrupt 0: Disable 1: Enable

REG_IR_TX_SR

• Name: IR Tx FIFO and interrupt status register

• Size: 32

• Address offset: 008h

• Read/write access: R

Bit	Symbol	Access	INI	Description
31:16	RSVD	R	-	Reserved
15	IR_TX_FIFO_EMPTY	R	0x0	0: Not empty 1: Empty
14	IR_TX_FIFO_FULL	R	0x0	0: Not full 1: Full
13:8	IR_TX_FIFO_OFFSET	R	0x0	Tx FIFO offset is from 0 to 32. Note After Tx last packet, hardware can’t clear Tx FIFO offset.
7:5	RSVD	R	-	Reserved
4	IR_TX_STATUS	R	0x0	0: Idle 1: Run
3	RSVD	R	-	Reserved
2	IR_TX_FIFO_OVER_INT_STATUS	R	0x0	Tx FIFO overflow interrupt 0: Interrupt inactive 1: Interrupt active
1	IR_TX_FIFO_LEVEL_INT_STATUS	R	0x0	When Tx FIFO offset <= threshold value, interrupt is triggered. 0: Interrupt inactive 1: Interrupt active
0	IR_TX_FIFO_EMPTY_INT_STATUS	R	0x0	Tx FIFO empty interrupt 0: Interrupt inactive 1: Interrupt active

REG_IR_TX_COMPE_DIV

• Name: IR Tx compensation division register

• Size: 32

• Address offset: 00Ch

• Read/write access: R/W

Bit	Symbol	Access	INI	Description
31:12	RSVD	R	-	Reserved
11:0	TX_COMPE_DIV	R/W	0x0	IR_TX_CLK_Period = SCLK/(TX_COMPE_DIV + 1)

REG_IR_TX_INT_CLR

• Name: IR Tx FIFO and interrupt clear register

• Size: 32

• Address offset: 010h

• Read/write access: R/W

Bit	Symbol	Access	INI	Description
31:4	RSVD	R	-	Reserved
3	IR_TX_FIFO_OVER_INT_CLR	R/W		Tx FIFO overflow interrupt Write 1 to clear
2	IR_TX_FIFO_LEVEL_INT_CLR	R/W		When Tx FIFO offset <= threshold value, interrupt is triggered. Write 1 to clear
1	IR_TX_FIFO_EMPTY_INT_CLR	R/W		Tx FIFO empty interrupt Write 1 to clear
0	IR_TX_FIFO_CLR	R/W		Write 1 to clear Tx FIFO

REG_IR_TX_FIFO

• Name: IR Tx FIFO register

• Size: 32

• Address offset: 014h

• Read/write access: R/W

Bit	Symbol	Access	INI	Description
31	IR_TX_DATA_TYPE	R/W	0	Data type 0: Inactive carrier (no carrier) 1: Active carrier (carrier)
30	IR_TX_DATA_END_FLAG	R/W	0	0: Normal packet 1: Last packet
29:28	IR_TX_COMPENSATION	R/W	0	0x0: IR_TX_CLK_Period = Tsys_clk * IR_CLK_DIV 0x1: IR_TX_CLK_Period = (1 + 1/2) Tsys_clk * IR_CLK_DIV 0x2: IR_TX_CLK_Period = (1 + 1/4) Tsys_clk * IR_CLK_DIV 0x3: IR_TX_CLK_Period = Tsys_clk * (IR_TX_COMPE_DIV + 1)
27:0	IR_TX_DATA_TIME	R/W	0	Real active time = (IR_TX_DATA_TIME + 1) * IR_TX_CLK_Period

REG_IR_RX_CONFIG

• Name: IR Rx configuration register

• Size: 32

• Address offset: 018h

• Read/write access: R/W

Bit	Symbol	Access	INI	Description
31:29	RSVD	R	-	Reserved
28	IR_RX_START	R/W	0x0	0: FSM stops at idle state. 1: FSM runs.
27	IR_RX_START_MODE	R/W	0x0	0: Manual mode, IR_RX_MAN_START control 1: Auto-mode, Trigger-mode control
26	IR_RX_MAN_START	R/W	0x0	If IR_RX_TRIGGER_MODE =0, writing 1 means starting to check the waveform.
25:24	IR_RX_TRIGGER_MODE	R/W	0x0	00: High --> low trigger 01: Low -> high trigger 10: High -> low or low ->high trigger
23:21	IR_RX_FILTER_STAGETX	R/W	0x0	0x0: Filter <= 20ns glitch 0x1: Filter <= 30ns glitch 0x2: Filter <= 40ns glitch 0x3: Filter <= 50ns glitch …
20	RSVD	R	-	Reserved
19	IR_RX_FIFO_ERROR_INT_MASK	R/W	0x0	Rx FIFO error read interrupt When Rx FIFO is empty, read Rx FIFO and trigger interrupt. 0: Unmask 1: Mask
18	IR_RX_CNT_THR_INT_MASK	R/W	0x0	Rx count threshold interrupt 0: Unmask 1: Mask
17	IR_RX_FIFO_OF_INT_MASK	R/W	0x0	Rx FIFO overflow 0: Unmask 1: Mask
16	IR_RX_CNT_OF_INT_MASK	R/W	0x0	RX counter overflow 0: Unmask 1: Mask
15	IR_RX_FIFO_LEVEL_INT_MASK	R/W	0x0	Rx FIFO level interrupt 0: Unmask 1: Mask When Rx FIFO offset >= threshold value, this interrupt is triggered.
14	IR_RX_FIFO_FULL_INT_MASK	R/W	0x0	Rx FIFO full interrupt 0: Unmask 1: Mask
13	IR_RX_FIFO_DISCARD_SET	R/W	0x0	When FIFO is full, new data is send to FIFO. 0: Discard oldest data in FIFO. 1: Reject new data sending to FIFO.
12:8	IR_RX_FIFO_LEVEL_TH	R/W	0x0	Rx FIFO interrupt threshold When Rx FIFO depth > threshold value, this interrupt is triggered.
7:6	RSVD	R	-	Reserved
5	IR_RX_FIFO_ERROR_INT_EN	R/W	0x0	Rx FIFO error read interrupt When Rx FIFO is empty, reading the Rx FIFO triggers this interrupt. 0: Disable 1: Enable
4	IR_RX_CNT_THR_INT_EN	R/W	0x0	Rx count threshold interrupt 0: Disable 1: Enable
3	IR_RX_FIFO_OF_INT_EN	R/W	0x0	RX FIFO overflow 0: Disable 1: Enable
2	IR_RX_CNT_OF_INT_EN	R/W	0x0	RX counter overflow 0: Disable 1: Enable
1	IR_RX_FIFO_LEVEL_INT_EN	R/W	0x0	Rx FIFO level interrupt When Rx FIFO offset >= threshold value, this interrupt is triggered. 0: Disable 1: Enable
0	IR_RX_FIFO_FULL_INT_EN	R/W	0x0	Rx FIFO full interrupt 0: Disable 1: Enable

REG_IR_RX_SR

• Name: IR Rx FIFO and interrupt status register

• Size: 32

• Address offset: 01Ch

• Read/write access: R

Bit	Symbol	Access	INI	Description
31:18	RSVD	R	-	Reserved
17	IR_RX_FIFO_EMPTY	R	0x0	0: Not empty 1: Empty
16	IR_RX_FIFO_FULL	R	0x0	0: Not full 1: Full
15:14	RSVD	R	-	Reserved
13:8	IR_RX_FIFO_OFFSET	R	0x0	Rx FIFO offset
7	IR_RX_STATE	R	0x0	0: Idle 1: Run
6	RSVD	R	-	Reserved
5	IR_RX_FIFO_ERROR_INT_STATUS	R	0x0	Rx FIFO error read interrupt status When Rx FIFO is empty, reading the Rx FIFO triggers this interrupt. 0: Interrupt is inactive 1: Interrupt is active
4	IR_RX_CNT_THR_INT_STATUS	R	0x0	Rx count threshold interrupt status 0: Interrupt is inactive 1: Interrupt is active
3	IR_RX_FIFO_OF_INT_STATUS	R	0x0	Rx FIFO overflow interrupt status 0: Interrupt is inactive 1: Interrupt is active
2	IR_RX_CNT_OF_INT_STATUS	R	0x0	Rx counter overflow interrupt status 0: Interrupt is inactive 1: Interrupt is active
1	IR_RX_FIFO_LEVEL_INT_STATUS	R	0x0	Rx FIFO level interrupt status 0: Interrupt is inactive 1: Interrupt is active
0	IR_RX_FIFO_FULL_INT_STATUS	R	0x0	Rx FIFO full interrupt status 0: Interrupt is inactive 1: Interrupt is active

REG_IR_RX_INT_CLR

• Name: IR Rx FIFO and interrupt clear register

• Size: 32

• Address offset: 020h

• Read/write access: R/W

Bit	Symbol	Access	INI	Description
31:9	RSVD	R	-	Reserved
8	IR_RX_FIFO_CLR	R/W		Write 1 to clear Rx FIFO
7:6	RSVD	R	-	Reserved
5	IR_RX_FIFO_ERROR_INT_CLR	R/W		Rx FIFO error read interrupt Write 1 to clear
4	IR_RX_CNT_THR_INT_CLR	R/W		Rx count threshold interrupt Write 1 to clear
3	IR_RX_FIFO_OF_INT_CLR	R/W		Rx FIFO overflow interrupt Write 1 to clear
2	IR_RX_CNT_OF_INT_CLR	R/W		Rx counter overflow interrupt Write 1 to clear
1	IR_RX_FIFO_LEVEL_INT_CLR	R/W		Rx FIFO level interrupt Write 1 to clear
0	IR_RX_FIFO_FULL_INT_CLR	R/W		Rx FIFO full interrupt Write 1 to clear

REG_IR_RX_CNT_INT_SEL

• Name: IR Rx count threshold configure register

• Size: 32

• Address offset: 024h

• Read/write access: R/W

Bit	Symbol	Access	INI	Description
31	IR_RX_CNT_THR_TRIGGER_LV	R/W	0x0	Trigger level 0: When low level counter >= threshold, trigger interrupt 1: When high level counter >= threshold, trigger interrupt
30:0	IR_RX_CNT_THR	R/W	0x0	31-bits threshold

REG_IR_RX_FIFO

• Name: IR Rx FIFO register

• Size: 32

• Address offset: 028h

• Read/write access: R

Bit	Symbol	Access	INI	Description
31	IR_RX_LEVEL	R	0x0	Rx Level 1: High level 0: Low level
30:0	IR_RX_CNT	R	0x0	31 bits cycle duration

REG_IR_VERSION

• Name: IR version register

• Size: 32

• Address offset: 02Ch

• Read/write access: R

Bit	Symbol	Access	INI	Description
31:0	IR_VERSION	R	0x1410150A	IR IP version

REG_IR_DUMMY

• Name: IR Dummy Register

• Size: 32

• Address offset: 030h

• Read/write access: R

Bit	Symbol	Access	INI	Description
31:16	RSVD	R	-	Reserved
15:0	DUMMY	R	0x0	Reserved for HW