DESCRIPTION OF PIN FUNCTIONS
PIN NO.
33
34
96
97
98
99
100
102
103
104
105
106
107
108
109
110
111:118
119
120
Note 0:
Power On (Note 4)
Button Input (Note 4)
GENERAL PURPOSE I/O
GP I/O; IRQ in (Note 4)
GP I/O; IRQ in (Note 4)
GP I/O; WD Timer Output /IRRX (Note 4)
GP I/O; Power Led output /IRTX (Note 4)
GP I/O; GP Address Decode (Note 4)
GP I/O; GP Write Strobe (Note 4)
GP I/O; Joy Read Strobe/JOYCS (Note 4)
GP I/O; Joy Write Strobe (Note 4)
GP I/O; IDE2 Output Enable/8042 P20 (Note 4)
GP I/O; Serial EEPROM Data In/AB_DATA (Note 4)
GP I/O; Serial EEPROM Clock (Note 4)
GP I/O; Serial EEPROM Enable (Note 4)
GP I/O; 8042 P21 (Note 4)
BIOS BUFFERS
ROM Bus (I/O to the SD Bus) (Note 4)
ROM Chip Select (only used for ROM) (Note 4)
RD[0:7]
nROMCS
I/O4
I
I
GP10
GP11
GP12
GP13
GP14
GP15
GP16
GP17
GP20
GP21
GP23
GP24
GP25
I/O4
I/O4
I/O4
I/O24
I/O4
I/O4
I/O4
I/O4
I/O4
I/O8
I/O8
I/O4
I/O4
I/O4
NAME
SYMBOL
nPowerOn
Button_In
BUFFER TYPE
I/O24
I/O24
SOFT POWER MANAGEMENT INTERFACE
GP I/O; Serial EEPROM Data Out/AB_CLK (Note 4) GP22
ROM Output Enable (DIR) (only used for ROM) (Note 4) nROMDIR
Note 1:
Note 2:
Note 3:
Note 4:
The interrupt request is output on one of the IRQx signals as 024 buffer type. If EPP or
ECP Mode is enabled, this output is pulsed low, then released to allow sharing of interrupts.
In this case, the buffer type is OD24. Refer to the configuration section for more
information.
nCS -This pin is the active low chip select; it must be low for all chip accesses. For 12 bit
addressing, SA0:SA11, this input should be tied to GND. For 16 bit address qualification,
address bits SA12:SA15 can be "ORed" together and applied to this pin. If IDE2 is not
used, SA12 can be connected to nCS, pin 27 to SA13, pin 28 to SA14 and pin 29 to SA15
nYY - The "n" as the first letter of a signal name indicates an "Active Low" signal
nHDCS2 and nHDCS3 require a pull-up to ensure a logic high at power-up when used for
IDE2 until the Active Bit is set to 1.
See Table 1, Multifunction Pins with GPI/O and Other Alternate Functions.
8
SMSC [ SMSC CORPORATION ]
