w83977atf Winbond Electronics Corp America, w83977atf Datasheet - Page 157

• Manufacturer Part Number: w83977atf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

CRF1 (Default 0x00)
and no external input to the device. These 5 bits are controlled by the IR, 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 enabled.
These bits indicate that the individual device's idle timer expires due to no I/O access, no IRQ,
Bit 5 - 4: Reserved. Return zero when read.
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 : Reserved. Return zero when read.
Bit 6: IRIDLSTS. IR idle status
= 1
= 0
= 1
= 0
= 1
= 0
= 1
= 0
= 1
= 0
IR is now in the working state.
IR is now in the sleeping state due to no IR access, no IRQ, the receiver is
now waiting for a start bit, and the transmitter shift register is now empty in a preset
expiry time period.
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, ACK , PE, SLCT, and ERR pins in a
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.
preset expiry time period.
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Publication Release Date:April 1998
W83977ATF
PRELIMINARY
Revision 0.52