W83977ATF Datasheet, PDF (157/207 Pages) Winbond – WINBOND I/O

W83977ATF
PRELIMINARY
CRF1 (Default 0x00)
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 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.
Bit 7 : Reserved. Return zero when read.
Bit 6: IRIDLSTS. IR idle status
= 0 IR is now in the working state.
= 1 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.
Bit 5 - 4: Reserved. Return zero when read.
Bit 3: PRTIDLSTS. Printer port idle status.
= 0 printer port is now in the working state.
= 1 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
preset expiry time period.
Bit 2: FDCIDLSTS. FDC idle status.
= 0 FDC is now in the working state.
= 1 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.
Bit 1: URAIDLSTS. UART A idle status.
= 0 UART A is now in the working state.
= 1 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.
Bit 0: URBIDLSTS. UART B idle status.
= 0 UART B is now in the working state.
= 1 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.
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Publication Release Date:April 1998
Revision 0.52