|
楼主 |
发表于 2009-3-2 13:40:24
|
显示全部楼层
回复 2# 的帖子
我最初的想法也是直接使用FPGA芯片对IDE硬盘进行ATA协议编程(使用的是ATA-6协议),但是研究了一段时间,没有什么进展。
一是由于我以前没有做过什么实际的项目,就玩过几天单片机,二是我下载到的ATA-6的协议是英文版本的,由于经验少,不少地方我看不明白,所以最开始用单片机做了个板子总是调不通。这才转而想使用专用芯片。
譬如,ATA协议里面,IDE硬盘四十个脚当中有一个DASP-引脚我就不太明白。
我将协议里面的描写摘录下来:
Signal summary部分对DASP-的说明:
5.2.3 DASP- (Device active, device 1 present)
During the reset protocol, DASP- shall be asserted by Device 1 to indicate that the device is present. At all other times, DASP- may be asserted by the selected active device.
Driver types and required termination部分对DASP-的说明如下:
Signal:DASP- Source:Device Driver type:OC Device:10K PU Notes:6、9
6. Pull-up values are based on +5 V Vcc. Except for the pull-up on PDIAG-:CBLID- whic
VCC for backward compatibility, pull-ups may be to VDD3. For systems supporting Ul
greater than 4, the host pull-up on IORDY:DDMARDY-:DSTROBE should be to VDD3.
9 .The host shall not drive DASP-. If the host connects to DASP- for any purpose, the host shall ensure that the signal level detected on the interface for DASP- shall maintain VoH and VoL compatibility, given the I oH and IoL requirements of the DASP- device drivers
按照上面的说明,DASP-是属于硬盘驱动的OC门,那我用单片机连接的时候是不是给这个脚外接一个10K的上拉电阻和一个5V的电源,然后接到单片机引脚上去?或者我根本就不用管这个脚?
希望有过相关开发经验的高手能指导一下。 |
|