
Chapter 3 |
| Hardware | |
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| Pin # | Signal | Description |
| 25 | PIOR* | Drive I/O Read – Strobe signal for read functions. Negative edge enables data |
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| from a register or data port of the drive onto the host data bus. Positive edge |
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| latches data at the host. |
| 26 | GND | Digital Ground |
| 27 | IOChRdy | I/O Channel Ready – When negated, extends the host transfer cycle of any host |
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| register access when the drive is not ready to respond to a data transfer request. |
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| High impedance if asserted. |
| 28 | Reserved | Reserved – Not used (through 470 ohm resistor to ground) |
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| 29 | PDACK* | DMA Channel Acknowledge – Used by the host to acknowledge data has been |
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| accepted or data is available. Used in response to DMARQ asserted. |
| 30 | GND | Digital Ground |
| 31 | PIRQ | Interrupt Request – Asserted (IRQ 14) by drive when it has pending interrupt |
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| request (PIO transfer of data to or from the drive to the host). |
| 32 | NC | Not connected |
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| 33 | LA18 | Latch Address 18 – Used to indicate which byte in the ATA command block or |
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| control block is being accessed. |
| 34 | NC | Not connected (through 0.047 ∝ f capacitor to ground) |
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| 35 | LA17 | Latch Address 17 – Used to indicate which byte in the ATA command block or |
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| control block is being accessed. |
| 36 | LA19 | Latch Address 19 – Used to indicate which byte in the ATA command block or |
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| control block is being accessed |
| 37 | IDE_PCS1 | IDE Chip Select 1 – Used to select the |
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| 38 | IDE_PCS3 | IDE Chip Select 3 – Used to select the |
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| 39 | Reserved | Reserved – Not used |
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| 40 | GND | Digital Ground |
| 41 | +5V | +5 volts ±5% power supply |
| 42 | +5V | +5 volts ±5% power supply |
| 43 | GND | Digital Ground |
| 44 | NC | Not connected |
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Notes: The shaded area denotes power or ground. The signals marked with * indicate active low.
28 | Reference Manual | CoreModule 420 |