w83977tf Winbond Electronics Corp America, w83977tf Datasheet - Page 130

• Manufacturer Part Number: w83977tf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

CRF1 (Default 0x00)
CRF2 (Default 0x00)
Bit 7 - 4: Reserved. Return zero when read.
Bit 3 - 0: Devices' idle status.
These bits indicate that the individual device's idle timer expires due to no I/O access, no IRQ,
and no external input to the device. These 4 bits are controlled by the printer port, FDC, UART A,
and UART B power down machines individually. Writing a 1 clears this bit, and writing a 0 has no
effect. Note that: the user is not supposed to change the status while the power management
function is
Bit 3: PRTIDLSTS. Printer port idle status.
Bit 2: FDCIDLSTS. FDC idle status.
Bit 1: URAIDLSTS. UART A idle status.
Bit 0: URBIDLSTS. UART B idle status.
Bit 7 - 4: Reserved. Return zero when read.
Bit 3 - 0: Devices' trap status.
These bits indicate that the individual device wakes up due to any I/O access, IRQ, and external
input to the device. The device's idle timer reloads the preset expiry depending on which device
wakes up. These 4 bits are controlled by the printer port, FDC, UART A, and UART B power down
machines respectively. Writing a 1 clears this bit, and writing a 0 has no effect. Note that: the
user is not supposed to change the status while power management function is enabled.
Bit 3: PRTTRAPSTS. Printer port trap status.
= 0
= 1
= 0
= 1
= 0
= 1
= 0
= 1
= 0
= 1
enabled.
printer port is now in the working state.
printer port is now in the sleeping state due to no printer port access, no IRQ, no DMA
acknowledge, and no transition on BUSY,
preset expiry time period.
FDC is now in the working state.
FDC is now in the sleeping state due to no FDC access, no IRQ, no DMA
acknowledge, and no enabling of the motor enable bits in the DOR register in a
preset expiry time period.
UART A is now in the working state.
UART A is now in the sleeping state due to no UART A access, no IRQ, the receiver
is now waiting for a start bit, the transmitter shift register is now empty, and no
transition on MODEM control input lines in a preset expiry time period.
UART B is now in the working state.
UART B is now in the sleeping state due to no UART A access, no IRQ, the receiver
is now waiting for a start bit, the transmitter shift register is now empty, and no
transition on MODEM control input lines in a preset expiry time period.
the printer port is now in the sleeping state.
the printer port is now in the working state due to any printer port access, any IRQ,
any DMA acknowledge, and any transition on BUSY,
pins.
-119-
ACK
Publication Release Date: March 1998
, PE, SLCT, and
ACK
W83977TF
, PE, SLCT, and
PRELIMINARY
ERR
Revision 0.62
pins in a
ERR