Datasheet

Dual Serial UART with 128-Word FIFOs
MAX3109
42 Maxim Integrated
IrDA Register
The IrDA register 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, separate from whether IrDA pulse shaping is enabled or not.
Bits 7, 6, and 2: No Function
Bit 5: TxInv
Set the TxInv bit high to invert the logic at the TX_ output. This functionality is separate from IrDA operation.
Bit 4: RxInv
Set the RxInv bit high to invert the logic at the RX_ input. This functionality is separate from IrDA operation.
Bit 3: MIR
Set the MIR and IrDAEn bits high to select IrDA 1.1 (MIR) with 1/4th period pulse widths.
Bit 1: SIR
Set the SIR and IrDAEn bits high to select IrDA 1.0 pulses (SIR) with 3/16th period pulse widths.
Bit 0: IrDAEn
Set the IrDAEn bit high to program the MAX3109 to produce IrDA-compliant pulses at the TX_ output and expect IrDA-
compliant pulses at the RX_ input. If IrDAEn is set low, normal (non-IrDA) pulses are generated by the transmitter and
expected by the receiver. Use IrDAEn in conjunction with the SIR or MIR bits to select the pulse width.
Flow Level Register (FlowLvl)
FlowLvl is used for selecting the RxFIFO threshold levels used for auto software (XON/XOFF) and hardware (RTS_/
CTS_) flow control.
Bits 7–4: Resumex
The Resumex bits set the receive FIFO threshold at which an XON character is automatically sent in auto software flow
control mode or RTS_ is automatically asserted in AutoRTS mode. These flow control actions occur once the RxFIFO
is emptied to below the value in Resumex. This signals the far-end station to resume transmission. The threshold level
is calculated as 8 x Resumex. The resulting possible threshold-level range is 0 to 120 (decimal).
Bits 3–0: Haltx
The Haltx bits set the receive FIFO threshold level at which an XOFF character is automatically sent in auto software
flow control mode or RTS_ is automatically deasserted in AutoRTS mode. These flow control actions occur once the
RxFIFO is filled to above the value in Haltx. This signals the far-end station to halt transmission. The threshold level is
calculated as 8 x Haltx. The resulting possible threshold-level range is 0 to 120 (decimal).
ADDRESS: 0x0E
MODE: R/W
BIT 7 6 5 4 3 2 1 0
NAME
— — TxInv RxInv MIR — SIR IrDAEn
RESET
0 0 0 0 0 0 0 0
ADDRESS: 0x0F
MODE: R/W
BIT 7 6 5 4 3 2 1 0
NAME
Resume3 Resume2 Resume1 Resume0 Halt3 Halt2 Halt1 Halt0
RESET
0 0 0 0 0 0 0 0