OXCF950_06 Datasheet, PDF (42/66 Pages) Oxford Semiconductor – low cost asynchronous 16-bit PC card or Compact Flash UART device

OXFORD SEMICONDUCTOR, INC.
OXCF950 rev B DATA SHEET
logic 1 ⇒ Data will be transmitted and received in IrDA
format.
This function is only available in Enhanced mode. It
requires a 16x clock to function correctly.
MCR[7]: Baud rate prescaler select
logic 0 ⇒ Normal (divide by 1) baud rate generator
prescaler selected.
logic 1 ⇒ Divide-by-“M N/8” baud rate generator
prescaler selected.
Where M & N are programmed in CPR (ICR offset 0x01).
After a hardware reset, CPR defaults to 0x20 (divide-by-4)
and MCR[7] is reset to ‘0’. User writes to this flag will only
take effect in enhanced mode. See section 6.9.1.
6.7.2 Modem Status Register ‘MSR’
MSR[0]: Delta CTS#
Indicates that the CTS# input has changed since the last
time the MSR was read.
MSR[1]: Delta DSR#
Indicates that the DSR# input has changed since the last
time the MSR was read.
6.8 Other Standard Registers
MSR[2]: Trailing edge RI#
Indicates that the RI# input has changed from low to high
since the last time the MSR was read.
MSR[3]: Delta DCD#
Indicates that the DCD# input has changed since the last
time the MSR was read.
MSR[4]: CTS
This bit is the complement of the CTS# input. It is
equivalent to RTS (MCR[1]) during internal loop-back
mode.
MSR[5]: DSR
This bit is the complement of the DSR# input. It is
equivalent to DTR (MCR[0]) during internal loop-back
mode.
MSR[6]: RI
This bit is the complement of the RI# input. In internal loop-
back mode it is equivalent to the internal OUT1.
MSR[7]: DCD
This bit is the complement of the DCD# input. In internal
loop-back mode it is equivalent to the internal OUT2.
6.8.1 Divisor Latch Registers ‘DLL & DLM’
The divisor latch registers are used to program the baud
rate divisor. This is a value between 1 and 65535 by which
the input clock is divided by in order to generate serial
baud rates. After a hardware reset, the baud rate used by
the transmitter and receiver is given by:
Baudrate = ^InputClock
16 * Divisor
Where divisor is given by DLL + ( 256 x DLM ). More
flexible baud rate generation options are also available.
See section 6.10 for full details.
6.9 Automatic Flow Control
Automatic in-band flow control, automatic out-of-band flow
control and special character detection features can be
used when in Enhanced mode and are software compatible
with the 16C654. Alternatively, 16C750 compatible
automatic out-of-band flow control can be enabled when in
non-Enhanced mode. In 950 mode, in-band and out-of-
band flow controls are compatible with 16C654, with the
addition of fully programmable flow control thresholds.
6.8.2 Scratch Pad Register ‘SPR’
The scratch pad register does not affect operation of the
rest of the UART in any way and can be used for
temporary data storage. The register may also be used to
define an offset value to access the registers in the
Indexed Control Register set. For more information on
Indexed Control registers see Table 27 and section 6.11.
6.9.1 Enhanced Features Register ‘EFR’
Writing 0xBF to LCR enables access to the EFR and other
Enhanced mode registers. This value corresponds to an
unused data format. Writing 0xBF to LCR will set LCR[7]
but leaves LCR[6:0] unchanged. Therefore, the data format
of the transmitter and receiver data is not affected. Write
the desired LCR value to exit from this selection.
DS-0027 Feb 06
External—Free Release
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