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Henry, My first thought in answer to your question is: I don't think anybody should use DC coupled SATA. Besides that comment, DC coupled devices should go to their common-mode (defined as 250mV in ATA-7). AC coupled devices may have a different bias point, and must comply overall with the 2.0V restrictions in the spec. John -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, September 22, 2004 9:53 AM To: John Masiewicz; [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: [t13] "Quiescent" bus Hi John. So should the Tx driver be disabled whether dc or ac coupled? If yes, are there restrictions (other than the coupling cap value selected) on the CM voltage when ac coupled? Thanks! Regards, Henry -----Original Message----- From: John Masiewicz [mailto:[EMAIL PROTECTED] Sent: Wednesday, September 22, 2004 8:41 AM To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: [t13] "Quiescent" bus Henry, It means c), disabling the Tx driver. It is not allowed to drive to a 1 or 0 state. This is to prevent biases when turning back on; there are also restrictions on common mode voltages that must be observed. John -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, September 20, 2004 6:22 PM To: [EMAIL PROTECTED] Subject: [t13] "Quiescent" bus This message is from the T13 list server. To T13, What is meant by "the bus in a quiescent" state. There are several references (in both T13 & SerialATA drafts) that mention (the bus) "quiescent". Does this refer to: a) holding the differential outputs static (i.e. logical equiv of a 1 or 0 differentially)? b) driving the bus to DC Idle c) disabling the Tx driver or ??? Any info/explaination of what this is would be greatly appreciated! Thanks!! Regards, Henry
