lan91c95 Standard Microsystems Corp., lan91c95 Datasheet - Page 46

• Manufacturer Part Number: lan91c95
• Description: Isa/pcmcia Full Duplex Single-chip Ethernet And Modem Controller With Ram
• Manufacturer: Standard Microsystems Corp.

8022h - Modem Configuration and Status Register (MCSR) Address 8022h
Bit 7 - Changed: This bit is the logical OR of the
CREADY/-Bsy and (RINGEVENT bit logically
anded with RINGENABLE) states.
Bit 6 - SigChg: If this bit is a one, the function is
enabled (configured), the Changed bit controls
the nSTSCHG pin.
function is disabled, the nSTSCHG pin is set to
a high.
Bit 5 - IOIs8: This bit when set, indicates that
the Host can only do 8 bit cycles (on D7-D0). In
the case of the IOIs8 bit being cleared (0),
during Reset and Power up for example, the PIN
MIS16 will override the IOIs8 default, setting
the bit (1).
Bit 4 - ResurvedBit 3 - Audio: This bit controls
the audio pass through of the digital audio.
When
three-stated.
passed to the SPKROUT pin.
Bit 2 - PwrDwn: When set (1), this bit puts the
modem into powerdown mode. The modem is
also put into powerdown mode when the Enable
Function bit is cleared. When in powerdown,
the MRINGIN signal is blocked from going to the
ringing output signal.
powerdown (when PwrDwn is cleared (1) and
Enable Function in the MCOR (bit 0) is set (1)),
Changed
7
0
cleared,
SigChg
When set, the SPKRIN pin is
6
0
the
If this bit is low or the
SPKROUT
When taken out of
IOIs8
5
0
Reserved
pin
4
0
is
46
the modem is awakened by a pulse on the
output ringing signals as appropriate. The pulse
duration is determined by the input signal
MRINGIN.
outputs.
Bit 1 - Intr: This bit is read/set to a one when
this function is requesting interrupt service. It is
cleared depending upon the setting of IntrACK.
When this bit and Enable IREQ Routing are set,
-IREQOut is asserted.
The Intr bit can be reset the following ways and
priority ranging from 1=highest to 3=lowest:
1)
2)
3)
Bit 0 - IntrACK: This bit controls the clearing of
the Intr bit. When this bit is cleared, Intr reflects
the function's interrupt status. When this bit is
set, the Intr bit must be cleared by the host
writing a 0 into it.
additional service (indicated by leaving MINT
active) the Intr bit will remain asserted when the
host writes the 0.
Audio
3
0
A hardware reset/power up
The function ie. interrupt source can only
reset this field to zero (0) if the IntrACK field
is
The host system can only reset this field to
a zero (0) if the IntrACK bit is set to a one
(1)
reset to zero (0)
Pwrdwn
MRINGIN is then passed to the
2
0
If the function requires
Intr
1
0
IntrACK
0
0