
W83877AF
Publication Release Date: Dec. 1996
Preliminary Version 0.52
- 8 -
1.3 Game Port/Power Down Interface
If Bit 3 of CR16 (GMDRQ) is 1, Bit 4 of CR3 (GMODS0) determines whether the game port is in
Adapter mode or Portable mode (default is Adapter mode). If Bit 3 of CR16 is 0, pin 39 and 41 are
used for DMA A operation.
SYMBOL
PIN
I/O
FUNCTION
GMRD
41
OUT
8t
When CR16 Bit 3 (GMDRQ) = 1, Adapter mode: Game port
read control signal.
PFDCEN
OUT
8t
Portable mode: When parallel port is selected as Extension
FDD/Extension 2FDD mode, this pin will be active. The active
state is dependent on bit 7 of CRA (PFDCACT), and default is
low active.
DACK_A
IN
t
When CR16 Bit 3 (GMDRQ) = 0, DMA acknowledge signal A.
GMWR
39
OUT
8t
When CR16 Bit 3 (GMDRQ) = 1, Adapter mode: Game port
write control signal.
PEXTEN
OUT
8t
Portable mode: When a particular extended mode is selected for
the parallel port, this pin will be active. The extended modes
include Extension Adapter mode, EPP mode, ECP mode, and
ECP/EPP mode, which are selected using bit 3 - bit 0 of CRA.
The active state is dependent on bit 6 of CRA (PEXTACT); the
default is low active.
DRQ_A
OUT
8t
When CR16 Bit 3 (GMDRQ) = 0: DMA request signal A.
PDCIN
3
IN
t
This input pin controls the chip power down. When this pin is
active, the clock supply to the chip will be inhibited and the
output pins will be tri-stated as defined in CR4 and CR6. The
PDCIN is pulled down internally. Its active state is defined by bit
4 of CRA (PDCHACT). Default is high active.
DACK_N
IN
t
DMA acknowledge signal D.
IRSL1
OUT
12t
IR module mode select 1.
IRRXH/IRSL0
I/O
12t
When input pin, high speed IR received terminal. When as
output pin, IR module mode select 0. Input or output are definied
in high speed IR register.