DESCRIPTION OF PIN FUNCTIONS
PIN
No./QFP
99
100
97
94
92
75:68
66
67
83
82
81
77
80
79
78
59
58
57
56
64
63
Note:
Note 1:
Note 2:
BUFFER TYPE
PER FUNCTION
(NOTE 1)
I/I
O4/I
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
SYMBOL
nCTS2/
SA13
Data Terminal Ready/Sys Addr
1
nDTR2/
14
SA14
Data Set Ready 2/Sys Addr 15
1
nDSR2/
SA15
Data Carrier Detect 2/8042 P12
1
nDCD2/P12
Ring Indicator 2/8042 P16
1
nRI2/P16
PARALLEL PORT INTERFACE (17)
Parallel Port Data Bus
8
PD[0:7]
Printer Select
1
nSLCTIN
Initiate Output
1
nINIT
Auto Line Feed
1
nALF
Strobe Signal
1
nSTROBE
Busy Signal
1
BUSY
Acknowledge Handshake
1
nACK
Paper End
1
PE
Printer Selected
1
SLCT
Error at Printer
1
nERROR
KEYBOARD/MOUSE INTERFACE (6)
Keyboard Data
1
KDAT
Keyboard Clock
1
KCLK
Mouse Data
1
MDAT
Mouse Clock
1
MCLK
Keyboard Reset
1
KBDRST
(Note 3)
Gate A20
1
A20M
NAME
Clear to Send 2/Sys Addr 13
TOTAL
1
Note 3:
Note 4:
The "n" as the first letter of a signal name indicates an "Active Low" signal.
Buffered types per function on multiplexed pins are separated by a slash “/”. Buffer types in
parenthesis represent multiple buffer types for a single pin function.
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 FDC37M81x addressing modes.
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.
8
SMSC [ SMSC CORPORATION ]
