XR20M1172G28-0B Datasheet, PDF (40/55 Pages) Exar Corporation – TWO CHANNEL I2C/SPI UART WITH 64-BYTE FIFO

XR20M1172
TWO CHANNEL I2C/SPI UART WITH 64-BYTE FIFO
REV. 1.2.0
DLD[5:4]: Sampling Rate Select
These bits select the data sampling rate. By default, the data sampling rate is 16X. The maximum data rate will
double if the 8X mode is selected and will quadruple if the 4X mode is selected. See Table 14 below.
TABLE 14: SAMPLING RATE SELECT
DLD[5]
DLD[4]
SAMPLING RATE
0
0
16X
0
1
8X
1
X
4X
DLD[7:6]: Reserved
4.21 Enhanced Feature Register (EFR)
Enhanced features are enabled or disabled using this register. Bit 0-3 provide single or dual consecutive
character software flow control selection (see Table 15). When the Xon1 and Xon2 and Xoff1 and Xoff2 modes
are selected, the double 8-bit words are concatenated into two sequential characters. Caution: note that
whenever changing the TX or RX flow control bits, always reset all bits back to logic 0 (disable) before
programming a new setting.
EFR[3:0]: Software Flow Control Select
Single character and dual sequential characters software flow control is supported. Combinations of software
flow control can be selected by programming these bits.
EFR BIT-3
CONT-3
0
0
1
0
1
X
X
X
1
0
1
0
TABLE 15: SOFTWARE FLOW CONTROL FUNCTIONS
EFR BIT-2
CONT-2
EFR BIT-1
CONT-1
EFR BIT-0
CONT-0
TRANSMIT AND RECEIVE SOFTWARE FLOW CONTROL
0
0
0
No TX and RX flow control (default and reset)
0
X
X
No transmit flow control
0
X
X
Transmit Xon1, Xoff1
1
X
X
Transmit Xon2, Xoff2
1
X
X
Transmit Xon1 and Xon2, Xoff1 and Xoff2
X
0
0
No receive flow control
X
1
0
Receiver compares Xon1, Xoff1
X
0
1
Receiver compares Xon2, Xoff2
0
1
1
Transmit Xon1, Xoff1
Receiver compares Xon1 and Xon2, Xoff1 and Xoff2
1
1
1
Transmit Xon2, Xoff2
Receiver compares Xon1 and Xon2, Xoff1 and Xoff2
1
1
1
Transmit Xon1 and Xon2, Xoff1 and Xoff2,
Receiver compares Xon1 and Xon2, Xoff1 and Xoff2
0
1
1
No transmit flow control,
Receiver compares Xon1 and Xon2, Xoff1 and Xoff2
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