Maxtor 91792D7, 91024D4, 90750D3 Pin Description Table, PIN Name Signal Name Signal Description

AT INTERFACE DESCRIPTION

Pin Description Table

PIN NAME	PIN	I/O	SIGNAL NAME	SIGNAL DESCRIPTION
RESET -	01	I	Host Reset	Reset signal from the host system. Active during power up and inactive after.
DD0	17	I/O	Host Data Bus	16 bit bi-directional data bus between host and drive. Lower 8 bits used for register
				and ECC byte transfers. All 16 bits used for data transfers.
DD1	15	I/O
DD2	13	I/O
DD3	11	I/O
DD4	09	I/O
DD5	07	I/O
DD6	05	I/O
DD7	03	I/O
DD8	04	I/O
DD9	06	I/O
DD10	08	I/O
DD11	10	I/O
DD12	12	I/O
DD13	14	I/O
DD14	16	I/O
DD15	18	I/O
DMARQ	21	O	DMA Request	This signal is used with DMACK for DMA transfers. By asserting this signal, the
				drive indicates that data is ready to be transfered to and from the host.
DIOW -	23	I	Host I/O Write	Rising edge of Write strobe clocks data from the host data bus to a register on the
STOP				drive.
DIOR -	25	I	Host I/O Read	Read strobe enables data from a register on the drive onto the host data bus.
HDMARDY				DMA ready during UltraDMA data in bursts.
HSTROBE				Data strobe during UltraDMA data out bursts.
IORDY	27	O	I/O Channel Ready	This signal may be driven low by the drive to insert wait states into host I/O cycles.
DDMARDY				DMA ready during UltraDMA data out bursts.
-				Data strobe during UltraDMA data in bursts.
DSTROBE
CSEL	28		Cable Select	Used for Master/Slave selection via cable. Requires special cabling on host system
				and installation of Cable Select jumper.
DMACK -	29	I	DMA Acknowledge	This signal is used with DMARQ for DMA transfers. By asserting this signal, the
				host is acknowledging the receipt of data or is indicating that data is available.
INTRQ	31	O	Host Interrupt	Interrupt to the host asserted when the drive requires attention from the host.
			Request
IOCS16	32		Device 16 bit I/O	Obsolete
PDIAG -	34	I/O	Passed Diagnostic	Output by drive when in Slave mode; Input to drive when in Master mode.
DA0	35	I	Host Address Bus	3 bit binary address from the host to select a register in the drive.
DA1	33	I
DA2	36	I
CS0 -	37	I	Host Chip Select 0	Chip select from the host used to access the Command Block registers in the drive.
				This signal is a decode of I/O addresses 1F0 - 1F7 hex.
CS1 -	38	I	Host Chip Select 1	Chip select from the host used to access the Control registers in the drive. This
				signal is a decode of I/O addresses 3F6 - 3F7 hex.
DASP -	39	I/O	Drive Active/Drive 1	Time-multiplexed, open collector output which indicates that a drive is active, or that
			Present	device 1 is present.
GND	02	N/A	Ground	Signal ground.
	19
	22
	24
	26
	30
	40
KEY	20	N/A	Key	Pin used for keying the interface connector.

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