This message is from the T13 list server.
I'm resending this, because there have been no responses on the reflector.
Please reply.
==============================================================
----- Forwarded by James C Hatfield/Seagate on 08/19/2005 11:55 AM -----
"Edi Fraiman" <[EMAIL PROTECTED]> wrote on 08/17/2005 11:44:45 PM:
> I am HW Engineer in M-Systems.
> I have next question about ATA/ATAPI-6 standard.
> As I read from the standard that series termination resistors are
> required at both the host and the device for operation in any of the
> Ultra DMA modes.
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Table 6 - Typical series termination for Ultra DMA
Host Device
Signal Termination Termination
DIOR-:HDMARDY-:HSTROBE 22 ohm 82 ohm
DIOW-:STOP 22 ohm 82 ohm
CS0-, CS1- 33 ohm 82 ohm
DA0, DA1, DA2 33 ohm 82 ohm
DMACK- 22 ohm 82 ohm
DD15 through DD0 33 ohm 33 ohm
DMARQ 82 ohm 22 ohm
INTRQ 82 ohm 22 ohm
IORDY:DDMARDY-:DSTROBE 82 ohm 22 ohm
RESET- 33 ohm 82 ohm
NOTE - Only those signals requiring termination are listed in this table.
If a signal is not
listed, series termination is not required for operation in an Ultra DMA
mode. Figure 2
shows signals also requiring a pull-up or pull-down resistor at the host.
The actual
termination values should be selected to compensate for transceiver and
trace
impedance to match the characteristic cable impedance.
-------------------------------------------------------------------
>
> Does that mean that traces characteristic impedance (on the PCB) of
> all signals mentioned in Table 6 should be approximately 100 ohm?
>
>
>
>
>
> Best Regards,
>
>
> Edi Fraiman
> HW Engineer
> Embedded Division
>
> M-Systems Israel
> 7 Atir Yeda St.
> Kfar Saba 44425
> Israel
> Tel: +972 9 764 3686
> Fax: +972 3 548 8666
> [EMAIL PROTECTED]
> www.m-systems.com
>
