This site is under construction and is in a very rough form there are probably errors I have not seen yet so please enjoy, If I get a good positive response I may create more pages on varying topics I am interested in.
Contained in these pages you will find enough information to directly access the IDE Hard Disk Drive.
I cannot guarantee the accuracy of this information, Nor will I be responsible for any loses you may experience. Usage of this information is strictly at your own risk.
| Port | Direction | Description |
| BASE+0 | R/W | Data 16 Bit |
| BASE+1 | R/W | R - Error
code
W - Write precomp cylinder/4 |
| BASE+2 | R/W | Sector count for operation |
| BASE+3 | R/W | Sector number(CHS Mode)
Logical block address, Bits 0-7 (LBA Mode) |
| BASE+4 | R/W | Cylinder low (CHS Mode)
Logical block address, Bits 8-15 (LBA Mode) |
| BASE+5 | R/W | Cylinder high (CHS Mode)
Logical block address, Bits 16-23 (LBA Mode) |
| BASE+6 | R/W | Drive & Head (CHS Mode)
Logical block address, Bits 24-27 (LBA Mode) |
| BASE+7 | R/W | R - Status code
W - Command |
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Last command ended in error |
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Over index hole/marker |
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Correctable ECC, (Soft Error) |
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Data request, Sector buffer requires servicing (busy) |
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Seek complete |
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Write fault |
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Drive ready for R/W/S (Unless b4=0) |
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Busy. 1=Executing command, Ignore other bits. |
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Data address mark not found |
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Track 0 error |
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Command was aborted |
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Reserved, Unused, (Always 1?) |
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Target sector ID could not be found |
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Reserved, Unused, (Always 1) |
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ECC error, (uncorrectable error) |
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Bad block |
| Command | Description |
| 0x10 | Recalibrate |
| 0x2? | Read sector |
| 0x3? | Write sector |
| 0x3c | Write verify |
| 0x4? | Verify read |
| 0x50 | Format track (Don't use, You have been warned) |
| 0x7x | Seek to cylinder |
| 0x8x | Vendor unique |
| 0x90 | Diagnostics |
| 0x91 | Set parameters |
| 0x94 | Standby - immediate |
| 0x95 | Idle - immediate |
| 0x96 | Standby |
| 0x97 | Idle |
| 0x98 | Check power mode |
| 0x99 | Set sleep mode |
| 0x9A | Vendor unique |
| 0xA0 | ATAPI packet |
| 0xA1 | Get ATAPI params |
| 0xC0-0xC3 | Vendor unique |
| 0xC4 | Read multi |
| 0xC5 | Write multi |
| 0xC6 | Set multi mode |
| 0xC8 | Read DMA with retry |
| 0xC9 | Read DMA without retry |
| 0xCA | Write DMA with retry |
| 0xCB | Write DMA without retry |
| 0xE4 | Read buffer |
| 0xE8 | Write buffer |
| 0xE9 | Write same |
| 0xEC | Get ATA params (Drive ID) |
| 0xEF | Set features |
?1 without retry
?2 long with retry
?3 long without retry
The command 0xEC deserves special mention, It transfers 512 bytes of information that specify the drive parameters,
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| 0 | 2 | Bit map | 0 Reserved.
1-5 Vendor specific. 6 Removable controller and/or device. 7 Removable media device. 8-14 Vendor specific. 15 Reserved for non magnetic devices. |
| 2 | 2 | lh | Number of cylinders |
| 4 | 2 | - | Reserved |
| 6 | 2 | lh | Number of heads |
| 8 | 4 | - | Vendor specific |
| 12 | 2 | lh | Number of sectors per track |
| 14 | 6 | - | Vendor specific |
| 20 | 20 | ASCII | Serial number of drive |
| 40 | 4 | - | Vendor specific |
| 44 | 2 | lh | Number of long ECC bytes transferred on long operations. |
| 46 | 8 | ASCII | Firmware revision |
| 54 | 40 | ASCII | Controller model number |
| 94 | 2 | Bit map | 0-7 If 0x00 R/W multiple not implemented, 0x01-0xFF Max sectors that
can be transferred per interrupt on R/W multiple commands.
8-15 Vendor specific. |
| 96 | 2 | - | Reserved |
| 98 | 2 | Bit map | Capabilities
0-7 Vendor specific 8 DMA Supported by drive if 1 9 LBA Supported by drive if 1 10 IORDY can be disabled if 1 11 IORDY supported if 1, IORDY may be supported if 0 12 Reserved 13 If 1 standard standby timer values are supported, if 0 standby timer values are vendor specific. 14,15 Reserved |
| 100 | 2 | - | Reserved |
| 102 | 2 | lh | PIO Data transfer cycle timing |
| 104 | 2 | lh | DMA data transfer cycle timing. |
| 106 | 406 | - | Reserved |
IDE Connector pin outs
| RESET | GND | D7 | D8 | D6 | D9 | D5 | D10 | D4 | D11 | D3 | D12 | D2 | D13 | D1 | D14 | D0 | D15 | GND | N/C |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 |
| DMARQ | GND | DIOW | GND | DIOR | GND | IORDY | CSEL | DMACK | GND | INTRQ | IOCS16 | A1 | PDIAG | A0 | A2 | CS0 | CS1 | DASP | GND |
16 Bit interface
HDD Manufacturer sites
http://www.seagate.com
http://www.quantum.com
http://www.maxtor.com
http://www.fujitsu.com
http://www.wdc.com
http://www.nec.com
Send constructive comments, Error reports and updates to fred@houweling.com.au