Irda register flowlvl—flow level register, Max3107 spi/i, C uart with 128-word fifos and internal oscillator – Rainbow Electronics MAX3107 User Manual

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MAX3107

SPI/I

C UART with 128-Word FIFOs

and Internal Oscillator

The IrDA allows selection of IrDA SIR and MIR-compliant pulse shaping at the TX and RX interfaces. It also allows
inversion of the TX and RX logic, independently of whether IrDA is enabled or not.
Bits 7 and 6: No Function
Bit 5: TxInv
Set the TxInv bit high to invert the logic at the TX output. This is independent of IrDA operation.
Bit 4: RxInv
Set the RxInv bit high to invert the logic state at the RX input. This is independent of IrDA operation.
Bit 3: MIR
Set the MIR and IrDAEn bits high to select IrDA 1.1 (MIR) with 1/4 period pulse widths.
Bit 2: ShortIR
Set the ShortIR and IrDAEn bits high to select IrDA 1.0 (SIR) with the transmitter producing the minimum allowed pulse
widths of 1.63Fs.
Bit 1: SIR
Set the SIR bit and the IrDAEn bits high to select IrDA 1.0 pulses (SIR) with 3/16th period pulses.
Bit 0: IrDAEn
Set the IrDAEn bit high so that IrDA-compliant pulses are produced at the TX output and the MAX3107 receiver expects
such pulses at its Rx input. If IrDAEn is set to low (default), normal (nonIrDA) pulses are generated and expected at
the receiver. IrDAEn must be used in conjunction with the SIR, ShortIR, or MIR select bits.

FlowLvl is used for selecting the RxFIFO threshold levels used for software (XON/XOFF) and hardware (RTS/CTS) flow control.
Bits 7–4: Resume[7:4]
Resume[7:4] sets the transmit FIFO threshold at which an XON is automatically sent or RTS/CLKOUT is automati-
cally set low. This signals the far-end station to start transmission. The actual threshold level is calculated as 8 times
Resume[7:4]. The resulting level is in the range of 0 to 120.
Bits 3–0: Halt[3:0]
Halt[3:0] sets a receive FIFO threshold level at which an XOFF is automatically sent or RTS/CLKOUT is automatically
set high, depending on whether automatic software or hardware flow control is enabled. This signals the far-end sta-
tion to halt transmission. The actual threshold level is calculated as 8 times Halt[3:0]. Hence, the selectable threshold
granularity is eight. The resulting level is in the range of 0 to 120.

IrDA Register

FlowLvl—Flow Level Register

ADDRESS:

0x0E

MODE:

R/W

BIT

NAME

—

TxInv

RxInv

MIR

ShortIR

SIR

IrDAEn

RESET

ADDRESS:

0x0F

MODE:

R/W

BIT

NAME

Resume3

Resume2

Resume1

Resume0

Halt3

Halt2

Halt1

Halt0

RESET