DESCRIPTION OF PIN FUNCTIONS
PIN
No./QFP
97
94
92
68:75
67
66
82
83
79
80
78
77
81
56
57
58
59
63
64
Note 1:
NAME
Data Set Ready 2/Sys Addr 15
Data Carrier Detect 2/8042 P12
Ring Indicator 2/8042 P16
TOTAL
1
1
1
SYMBOL
nDSR2/
SA15
nDCD2/P12
nRI2/P16
PD[0:7]
nSLCTIN
nINIT
nALF
nSTROBE
BUSY
nACK
PE
SLCT
nERROR
KDAT
KCLK
MDAT
MCLK
KBDRST
(Note 3)
A20M
BUFFER
TYPE
I/I
I/IO24
I/IO24
IO24
OD24/O24
OD24/O24
OD24/O24
OD24/O24
I
I
I
I
I
IOD16
IOD16
IOD16
IOD16
O4
O4
PARALLEL PORT INTERFACE (17)
Parallel Port Data Bus
8
Printer Select
1
Initiate Output
1
Auto Line Feed
1
Strobe Signal
1
Busy Signal
1
Acknowledge Handshake
1
Paper End
1
Printer Selected
1
Error at Printer
1
KEYBOARD/MOUSE INTERFACE (6)
Keyboard Data
1
Keyboard Clock
1
Mouse Data
1
Mouse Clock
1
Keyboard Reset
1
Gate A20
1
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
For 12 bit addressing, SA0:SA11 only, nCS should be tied to GND. For 16 bit external
address qualification, address bits SA11:SA15 can be "ORed" together and applied to nCS.
The nCS pin functions as SA11 in full 16 bit Internal Address Qualification Mode. CR24.6
controls the FDC37B77x addressing modes.
The "n" as the first letter of a signal name indicates an "Active Low" signal.
KBDRST is active low.
The pull-down on this pin is always active including when the output driver is tristated
and regardless of the state of internal PWRGOOD.
The “activate” bit for the CIrCC is reset by VTR POR only. The V
CC
power-up default for
this pin is Logic “0”.
The “activate” bit for Serial Port 2 is reset by VTR POR only. The V
CC
power-up default for
this pin is Logic “1”.
8
SMSC [ SMSC CORPORATION ]
