ESDI接口的英文名称是（Enhanced Small Drive Interface），它是迈拓公司于1983年开发的。其特点是将编解码器放在硬盘本身之中，而不是在控制卡上，理论传输速度是前面所述的ST-506的2...4倍，一般可达到10Mbps。但其成本较高，与后来产生的IDE接口相比无优势可言，因此在九十年代后就被淘汰了。是老式硬盘的接口，它的电缆由两部分组成，ESDI 接口在接口卡侧的外观为34脚和20脚公插针：
ESDI接口
在硬盘侧为34脚的控制信号和 20 脚数据信号：
|
ESDI接口信号定义 |
34 脚的ESDI接口控制信号：
|
Pin |
Name |
Description |
|---|---|---|
|
2 |
|
Head Sel 3 |
|
4 |
|
Head Sel 2 |
|
6 |
|
Write Gate |
|
8 |
|
Config/Stat Data |
|
10 |
|
Transfer Acknowledge |
|
12 |
|
Attention |
|
14 |
|
Head Sel 0 |
|
16 |
|
Sect/Add MK Found |
|
18 |
|
Head Sel 1 |
|
20 |
|
Index |
|
22 |
|
Ready |
|
24 |
|
Transfer Request |
|
26 |
|
Drive Sel 1 |
|
28 |
|
Drive Sel 2 |
|
30 |
|
Drive Sel 3 |
|
32 |
|
Read Gate |
|
34 |
|
Command Data |
20 脚的ESDI接口数据信号定义：
|
Pin |
Name |
Description |
|---|---|---|
|
1 |
|
Drive Selected |
|
2 |
|
Sect/Add MK Found |
|
3 |
|
Seek Complete |
|
4 |
|
Address Mark Enable |
|
5 |
|
(reserved, for step mode) |
|
6 |
GND |
Ground |
|
7 |
|
Write Clock+ |
|
8 |
|
Write Clock- |
|
9 |
|
Cartridge Changed |
|
10 |
|
Read Ref Clock+ |
|
11 |
|
Read Ref Clock- |
|
12 |
GND |
Ground |
|
13 |
|
NRZ Write Data+ |
|
14 |
|
NRZ Write Data- |
|
15 |
GND |
Ground |
|
16 |
GND |
Ground |
|
17 |
|
NRZ Read Data+ |
|
18 |
|
NRZ Read Data- |
|
19 |
GND |
Ground |
|
20 |
GND |
Ground |