DATA15..0 - 16-bit bidirectional bus between host and drive. Back to top.
KEY - Missing pin to allow keyed cable to be fitted. Back to top.
DMARQ - DMA Request (optional). Is asserted by the device to signal that it is ready
to transfer data to the host. Back to top.
DIOW# - Drive I/O write strobe.
Data is clocked on the rising edge from the host to a drive register or data port.
STOP - The STOP signal can be asserted by the host during a UDMA burst to signal the
termination of the UDMA burst. Back to top.
DIOR# - Drive I/O read strobe.
Data is clocked on the falling edge from the drive register or data port to the host.
HDMARDY# - Asserted by the host to signal that it is ready to receive UDMA bursts.
A UDMA burst can be paused by the host negating the signal.
HSTROBE - Data is clocked into the drive on the rising and falling edges of HSTROBE during a UDMA burst.
The host can pause the UDMA burst by not generating the HSTROBE signal.
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IORDY - I/O Channel Ready (optional).
DDMARDY# - Asserted by the drive to signal that it is ready to receive UDMA bursts.
A UDMA burst can be paused by the drive negating the signal.
DSTROBE Data is clocked into the host on the rising and falling edges of DSTROBE during a UDMA burst.
The drive can pause the UDMA burst by not generating the DSTROBE signal.
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CSEL - Cable select is used to differentiate master from slave in a two-drive system.
This pin is connected to ground at the host. A cable select cable has 2-3 connections.
The first is to the host, the second to the master dive with the CSEL signal connected
and the 3rd to the slave drive with the CSEL signal disconnected.
CSEl is pulled up in the drive so when it is connected to the master connector
the pin is grounded and when it's connected to the slave connector it is high.
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DMACK# - DMA Acknowledge (optional). Used by the host to initiate DMA transfers
after the drive has asseretd DMARQ. Back to top.
INTRQ - Interrupt to the host system.
Interrupt is asserted when the drive has a pending interrupt if the drive is selected and
the nIEN (Interrupt enable) bit is cleared in the Device Control register.
The drive will negate the interrupt signal when there is a read to the status register to clear
the interrupt or there is a write to the command register to clear the interrupt.
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DA2..0 - Address. Address asserted by the host to access a specific register or
data port in the drive. Back to top.
PDIAG# - Passed diagnostics.
Used by slave to signal to master drive that slave has passed its internal diagnostics.
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CBLID# - Is used by the host to determine if an 80 way cable is fitted.
If CBLID# is connected to ground then there is an 80 way cable.
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CS0# CS1# - Drive I/O chip select decoded from host address lines.
When CS0# is active command block registers are selected.
When CS1# is active control block registers are selected.
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DASP# - Used during power up to signal to the master that a slave is present.
The rest of the time it indicates the drive is active. It can be used by the host
to control an LED.
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OBSOLETE - Was IOCS16 in ATA-2 specification now obsolete.
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OPTION - Drives can use pins A, B, C and D for selecting options with jumpers.
If a drive uses these pins for device selection then no jumper present means
the drive is Device 0. A jumper between pins B and D means the device is
selected via the cable select signal.
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5V LOGIC / MOTOR - The 5V supply for the drive logic and motor.
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