5. Host Interface (31 pins)
Pin symbols are listed in the order of ATAPI mode, DMA mode and AV mode. Pull up means that the pin should be pulled up by a resistor, “0” means low level output, and nc means No Connect.
(1)HCS0 (HOST chip select: input)/nc/nc This pin is pulled up by a resistor.
ATAPI: Chip select negative logic input signal from the host. This is connected with the CS1FX pin of the ATAPI interface. DMA/AV: This pin is not used.
(2)HCS1 (HOST chip select: input)/nc/nc This pin is pulled up by a resistor.
ATAPI: Chip select negative logic input signal from the host. This is connected with the CS3FX pin of the ATAPI interface. DMA/AV: This pin is not used.
(3)HA[2:0] (HOST address: input)/pull up/pull up
ATAPI: Address input signal for selecting internal registers from the host.
DMA/AV: This pin is not used, and should be pulled up by a resistor.
(4)XHRD (HOST read: input)/XHRD (HOST read: output)/
XSHDR0 (sector header 0: output)
ATAPI: Strobe negative logic input signal for reading data from the host.
DMA: Strobe negative logic input signal for reading data to the host.
AV: Negative logic output signal indicating the lead byte of the sector.
(5)XHWR (HOST write: input)/XHWR (HOST write: output)/DCK
(data clock: output)
ATAPI: Strobe negative logic input signal for writing data from the host.
DMA: Strobe negative logic output signal for writing data to the host.
AV: Clock output for data transfer.
(6)XHAC (HOST DMA acknowledge: input)/HDRQ (HOST DMA
request: input)/REQUEST (request:input) This pin is pulled up by a resistor.
ATAPI: DMA acknowledge negative logic input signal from the host.
DMA: DMA request input signal from the host.
AV: Data transfer request input signal.
(7)DASP (drive active/slave present: input/output)/pull up/pull up
ATAPI: Negative logic signal indicating that a slave drive is present or a drive is active; open drain signal.
DMA/AV: This pin is not used, and should be pulled up by a resistor.
(8)HDB[F:0] (HOST data bus: input/output)/HDB[F:0] (HOST data
bus: input/output)/7 “0”, XVFLAG,
DATA[7:0] (“0”, video error flag, data: output)
ATAPI/DMA:
AV: Low level is output from the upper 7 bits. The 8th bit from the upper side is an error flag output signal corresponding to the lower 8 bits. The lower 8 bits are video data output signals.
(9)HDRQ (HOST DMA request: output)/XHAC (HOST DMA
acknowledge: output)/XACK (acknowledge:output)
ATAPI: DMA data request positive logic output signal to the host;
DMA: DMA acknowledge negative logic output signal to the host.
AV: Data transfer acknowledge negative logic output signal.
(10)HINT (HOST interrupt: output)/pull up/pull up
ATAPI: Interrupt request positive logic output signal to the host;
DMA/AV: This pin is not used, and should be pulled up by a resistor.
(11)XS16
ATAPI: Negative logic signal indicating that a
signal. This is connected with the IOCS16 pin of the ATAPI interface.
DMA/AV: This pin is not used, and should be pulled up by a resistor.
(12)REDY (I/O channel ready: output)/pull up/pull up
ATAPI: Positive logic signal which is negated when a drive is
not ready to respond to a data transfer request; open drain signal. This is connected with the IORDY pin of the ATAPI interface.
DMA/AV: This pin is not used, and should be pulled up by a resistor.
(13)XPDI (passed diagnostics: input/output)/pull up/pull up
ATAPI: Negative logic signal indicating that diagnostics of the slave drive have been completed; open drain signal. This is connected with the PDIAG pin of the ATAPI interface. DMA/AV: This pin is not used, and should be pulled up by a resistor.
(14)XHRS (HOST reset: input)/nc/nc
ATAPI: Reset negative logic signal from the host; pulled up by a resistor.
DMA/AV: This pin is not used
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