OXCF950 Datasheet, PDF (41/66 Pages) Oxford Semiconductor – Single full-duplex asynchronous channel 128-byte deep transmitter / receiver FIFO

OXFORD SEMICONDUCTOR LTD.
Level 6:
CTS or RTS changed interrupt (ISR[5:0]=’100000’):
This interrupt is set whenever either of the CTS# or RTS#
pins changes state from low to high. It is cleared on an ISR
read of a level 6 interrupt.
6.6.4 Sleep Mode
For a channel to go into sleep mode, all of the following
conditions must be met:
• Sleep mode enabled (IER[4]=1 in 650/950 modes, or
IER[5]=1 in 750 mode):
• The transmitter is idle, i.e. the transmitter shift register
and FIFO are both empty.
• SIN is high.
• The receiver is idle.
6.7 Modem Interface
6.7.1 Modem Control Register ‘MCR’
MCR[0]: DTR
logic 0 ⇒ Force DTR# output to inactive (high).
logic 1 ⇒ Force DTR# output to active (low).
Note that DTR# can be used for automatic out-of-band flow
control when enabled using ACR[4:3] (see section 6.11.3).
MCR[1]: RTS
logic 0 ⇒ Force RTS# output to inactive (high).
logic 1 ⇒ Force RTS# output to active (low).
Note that RTS# can be used for automatic out-of-band flow
control when enabled using EFR[6] (see section 6.9.4 ).
MCR[2]: OUT1
logic 0 ⇒ Force OUT1# output low when loopback mode
is disabled.
logic 1 ⇒ Force OUT1# output high.
OUT1# is not normally bonded out in the OXCF950 except
in C950 mode, but is internally used for loopback testing
MCR[3]: OUT2
logic 0 ⇒ Force OUT2# output low when loopback mode
is disabled.
logic 1 ⇒ Force OUT2# output high.
OUT2# is not normally bonded out in the OXCF950 except
in C950 mode, but is internally used for loopback testing
MCR[4]: Loopback mode
logic 0 ⇒ Normal operating mode.
logic 1 ⇒ Enable local loop-back mode (diagnostics).
OXCF950 rev B DATA SHEET V 1.0
• The receiver FIFO is empty (LSR[0]=0).
• The UART is not in loopback mode (MCR[4]=0).
• Changes on modem input lines have been
acknowledged (i.e. MSR[3:0]=0000).
• No interrupts are pending.
A read of IER[4] (or IER[5] if a 1 was written to that bit
instead) shows whether the power-down request was
successful. The UART will fully retain its programmed state
whilst in power-down mode.
The channel will automatically exit power-down mode when
any of the conditions 1 to 7 becomes false. It may be
woken manually by clearing IER[4] (or IER[5] if the
alternate sleep mode is enabled).
Sleep mode operation is not available in IrDA mode.
In local loop-back mode, the transmitter output (SOUT) and
the modem outputs (DTR#, RTS#) are set in-active (high),
and the receiver inputs SIN, CTS#, DSR#, DCD#, and RI#
are all disabled. Internally the transmitter output is
connected to the receiver input and DTR#, RTS#, OUT1#
and OUT2# are connected to modem status inputs DSR#,
CTS#, RI# and DCD# respectively.
In this mode, the receiver and transmitter interrupts are
fully operational. The modem control interrupts are also
operational, but the interrupt sources are now the lower
four bits of the Modem Control Register instead of the four
modem status inputs. The interrupts are still controlled by
the IER.
MCR[5]: Enable XON-Any in Enhanced mode or enable
out-of-band flow control in non-Enhanced mode
650/950 modes (Enhanced mode):
logic 0 ⇒ XON-Any is disabled.
logic 1 ⇒ XON-Any is enabled.
In enhanced mode (EFR[4]=1), this bit enables the Xon-
Any operation. When Xon-Any is enabled, any received
data will be accepted as a valid XON (see in-band flow
control, section 6.9.3).
750 mode (Non-Enhanced mode):
logic 0 ⇒ CTS/RTS flow control disabled.
logic 1 ⇒ CTS/RTS flow control enabled.
In non-enhanced mode, this bit enables the CTS/RTS out-
of-band flow control.
MCR[6]: IrDA mode
logic 0 ⇒ Standard serial receiver and transmitter data
format.
Page 41