DAN-164 Datasheet, PDF (2/3 Pages) Exar Corporation – MIGRATING FROM THE ST16C2550 TO THE XR16L2750

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DATA COMMUNICATIONS APPLICATION NOTE
DAN164
TABLE 2: ST16C2550 AND XR16L2750 REGISTER SET DIFFERENCES
A2:A0 R/W
ST16C2550
LCR Bit-7 = 0 (Standard Register Set)
001 R/W Interrupt Enable Register (IER)
• Bit-7 = Not Used
• Bit-6 = Not Used
• Bit-5 = Not Used
• Bit-4 = Not Used
010
W FIFO Control Register (FCR)
• Bit-5 = Not Used
• Bit-4 = Not Used
010
R Interrupt Status Register (ISR)
• Bit-5 = Not Used
• Bit-4 = Not Used
100 R/W Modem Control Register (MCR)
• Bit-7 = Not Used
• Bit-6 = Not Used
• Bit-5 = Not Used
LCR Bit-7 = 0, FCTR Bit-6 = 1
111
W
N/A
111
R
N/A
LCR Bit-7 = 0, DLL = 0x00, DLM = 0x00
000
R
N/A
001
R
N/A
LCR = 0xBF (Enhanced Register Set)
000
R
N/A
000
W
N/A
001 R/W
N/A
010 R/W
N/A
100 R/W
N/A
101 R/W
N/A
110 R/W
N/A
111 R/W
N/A
XR16L2750
Interrupt Enable Register (IER)
• Bit-7 = Auto CTS# Interrupt Enable
• Bit-6 = Auto RTS# Interrupt Enable
• Bit-5 = Xoff Interrupt Enable
• Bit-4 = Sleep Mode Enable
FIFO Control Register (FCR)
• Bit-5 = TX FIFO Trigger Level Select Bit-1
• Bit-4 = TX FIFO Trigger Level Select Bit-0
Interrupt Status Register (ISR)
• Bit-5 = Auto RTS/CTS Interrupt
• Bit-4 = Xoff or Special Character Interrupt
Modem Control Register (MCR)
• Bit-7 = BRG Prescaler Select
• Bit-6 = IR Mode Enable
• Bit-5 = XonAny
Enhanced Mode Select Register (EMSR)
• 8X Sampling, LSR Interrupt Immediate, Auto RTS Hysteresis
Select (MSB), RS485 Output Inversion, FLVL select - TX or
RX FIFO
FIFO Level Register (FLVL)
• Current Level of the TX or RX FIFO
Device Revision (DREV)
Device ID (DVID) = 0x0A
FIFO Data Count Register (FC)
Trigger Level Register (TRG)
• Programmable Trigger Levels 1-64 for TX and RX FIFO
Feature Control Register (FCTR)
• RX/TX Programmable Trigger Level Select, Scratchpad Swap,
Trigger Table Select, Auto RS485 Enable, RX Infrared Input
Inversion, Auto RTS Hysteresis Select (LSB)
Enhanced Feature Register (EFR)
• Auto RTS/CTS Enable, Enable Enhanced (shaded) bits in
Standard Register Set, Software Flow Control Select
XON1
XON2
XOFF1
XOFF2
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