Datasheet

Dual Serial UART with 128-Word FIFOs
MAX3109
45Maxim Integrated
XON1 Register
The XON1 and XON2 register contents define the XON character used for automatic XON/XOFF flow control and/or
the special characters used for special-character detection. See the FlowCtrl register description for more information.
Bits 7–0: Bitx
These bits define the XON1 character if single character XON auto software flow control is enabled in FlowCtrl[7:4]. If
double-character flow control is selected in FlowCtrl[7:4], these bits constitute the least significant byte of the 2-byte
XON character. If special character detection is enabled in MODE2[4] and auto flow control is not enabled, these bits
define a special character.
If both special character detection and auto software flow control are enabled, XON1 defines the XON flow control
character.
Table 3. SwFlow[3:0] Truth Table
X = Don’t care
ADDRESS: 0x14
MODE: R/W
BIT 7 6 5 4 3 2 1 0
NAME
Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
RESET
0 0 0 0 0 0 0 0
RECEIVE FLOW
CONTROL
TRANSMIT FLOW
CONTROL/SPECIAL
CHARACTER DETECTION
DESCRIPTION
SwFlow3 SwFlow2 SwFlow1 SwFlow0
0 0 0 0 No flow control/no special character detection.
0 0 X X No receive flow control.
1 0 X X Transmitter generates XON1, XOFF1.
0 1 X X Transmitter generates XON2, XOFF2.
1 1 X X Transmitter generates XON1, XON2, XOFF1, and XOFF2.
X X 0 0 No transmit flow control.
X X 1 0
Receiver compares XON1 and XOFF1 and controls the transmitter
accordingly.
XON1 and XOFF1 special character detection.
X X 0 1
Receiver compares XON2 and XOFF2 and controls the transmitter
accordingly.
XON2 and XOFF2 special character detection.
X X 1 1
Receiver compares XON1, XON2, XOFF1, and XOFF2 and controls
the transmitter accordingly. XON1, XON2, XOFF1, and XOFF2 special
character detection.