
P R E L I M I N A R Y
AMD
25
Am79C930
PIN DESCRIPTIONS
Pins with Internal Pull Up or Pull
Down Devices
Several pins of the Am79C930 device include internal
pull up or pull down devices. With the exception of the
RESET pin, these pins are fully programmable as inputs
or outputs when the PCMCIA mode has been selected.
A subset of these pins is programmable when the ISA
Plug and Play mode has been selected. These pins will
come up after RESET in the high impedance state with
the pull up or pull down device actively determining the
value of the pin, unless an external driving source
overdrives the pull up or pull down device. VINITDN
bit (MIR9[2]) is used to turn off all pull up and pull
down devices.
The following list indicates those pins that contain pull
up and pull down devices:
PCMCIA Mode
Internal Device
Size of Internal
Pin Name
Type
Device
USER[6]/IRQ5
pull up
> 100K
Ω
USER[5]/IRQ4
pull up
> 100K
Ω
USER[4]/LA17
pull up
> 100K
Ω
USER[3]/SA16
pull up
> 100K
Ω
USER[2]/LA19
pull up
> 100K
Ω
USER[1]/IRQ12
pull down
> 100K
Ω
USER[0]/RFRSH
pull down
> 100K
Ω
LLOCKE/SA15
pull down
> 100K
Ω
ANTSLT
/LA23
pull up
> 100K
Ω
TXDATA
/LA20
pull up
> 100K
Ω
TXCMD/LA21
pull down
> 100K
Ω
RXC/IRQ10
pull up
> 100K
Ω
USER7/IRQ11
pull up
> 100K
Ω
LFPE
pull up
> 100K
Ω
HFPE
pull up
> 100K
Ω
RXPE
pull up
> 100K
Ω
ANTSLT
pull down
> 100K
Ω
TXCMD
pull up
> 100K
Ω
TXPE
pull up
> 100K
Ω
SDCLK
pull up
> 100K
Ω
SDDATA
pull up
> 100K
Ω
SDSEL
[3]
pull up
> 100K
Ω
SDSEL
[2]
pull up
> 100K
Ω
SDSEL
[1]
pull up
> 100K
Ω
ACT
pull up
> 100K
Ω
LNK
pull up
> 100K
Ω
TXMOD
pull up
> 100K
Ω
STSCHG
/BALE
pull up
> 100K
Ω
TXC
pull up
> 100K
Ω
Following the RESET operation, the Am79C930 firm-
ware or driver software should appropriately program
the D bits of TIR and TCR registers, and then set the FN
and EN bits of TIR and TCR registers to set the values
and directions of each of these programmable pins.
Once these operations have been performed, the soft-
ware should then program the INITDN bit of MIR9 in or-
der to disable all of the pull up and pull down devices.
Unused programmable pins should be programmed for
output mode, or may be left in the default high imped-
ance state if an external pull down or pull up device is left
connected to the pin. Unused programmable pins must
not be programmed for input mode with no external
source (pull-device or driver) connected and the INITDN
bit of MIR9 set to a 1, since this could lead to unaccept-
able levels of power consumption by the Am79C930 de-
vice. For more information on programmable pins, see
the Multi-Function Pins section.
Configuration Pins
PCMCIA
PCMCIA/ISA Bus Interface Select
Input
The value of this pin will asynchronously determine the
operating mode of the Am79C930 device, regardless of
the state of the RESET pin and regardless of the state of
the CLKIN pin. If the PCMCIA pin is tied to VCC, then the
Am79C930 controller will be programmed for PCMCIA
Bus Mode. If the PCMCIA pin is tied to VSS, then the
Am79C930 controller will be programmed for ISA Plug
and Play Bus Interface Mode.