Cable Detection Issues in D1410R1

1
Cable Detection Issues in D1410R1

• Kent H. Pryor
• Quantum Corporation
• December 8, 2000
• E00164R0

2
Previous Cable Detection Issues

• Non-compliant PDIAG from Device 1.
• 40 conductor detected as 80 at host
• 80 conductor detected as 40 at device
• Intel system riser PCB could not accommodate host
  detection.

3
Current Cable Detection Issues

• Host alternatives in different sections.
• Some methods required, others optional or not
  recommended.
• Combo method algorithm was incomplete.
• Combo method removed for wrong reason.

4
Cable Detection Discussion Goals

• View side-by-side summary of methods.
• Consensus on overall strategy.
• Direction for any needed proposals.

5
Combo method was in 5.2.11

• The host may sample CBLID- after a power-on or
  hardware reset in order to detect the presence or
  absence of an 80-conductor cable assembly by
  performing the following steps
• )The host shall wait until the power-on or
  hardware reset protocol is complete for all
  devices on the cable
• )If Device 1 is present, the host should issue
  IDENTIFY DEVICE or IDENTIFY PACKET DEVICE and use
  the returned data to determine that Device 1 is
  compliant with ATA-3 or subsequent standards. Any
  device compliant with ATA-3 or subsequent
  standards releases PDIAG- no later than after the
  first command following a power-on or hardware
  reset sequence and will not interfere with host
  detection of CBLID- in the next step.
• )The host shall wait until after it has issued an
  IDENTIFY DEVICE or IDENTIFY PACKET DEVICE command
  to Device 1 before detecting the state of CBLID-
  in order to detect the presence or absence of an
  80-conductor cable.
• )If a device supporting Ultra DMA modes greater
  than 2 is present, the host shall use Word 93 bit
  13 from the IDENTIFY DEVICE or IDENTIFY PACKET
  DEVICE data of that device to verify the presence
  of an 80-conductor cable.
• NOTE ? Older devices not in compliance with ATA-3
  or subsequent standards may continue to assert
  this signal providing a false indication of the
  cable type.
• If the host detects that CBLID- is connected to
  ground, an 80-conductor cable assembly is
  installed in the system or device 1 was asserting
  PDIAG- when the state of CBLID- was detected. If
  a device supporting Ultra DMA modes greater than
  2 is present in this condition, a value of 11 in
  Word 93 bits 14-13 from that device when CBLID-
  is detected to be connected to ground at the host
  confirms the presence of an 80-conductor cable.
  A value of 10 from the device when CBLID- is
  detected to be connected to ground at the host
  indicates that an attached device 1 is driving
  PDIAG- and the cable type can not be determined.
  If the host detects that this signal is not
  connected to ground, an 80-conductor cable
  assembly is not installed in the system. For this
  result, the value of Word 93 bit 13 of a device
  supporting Ultra DMA modes greater than 2 may be
  0 or 1 depending on host loading of CBLID-. See
  Annex B for a description of the non-standard
  device determination of cable type.

6
D1410R1 specifications for host
7
Cable Detection Alternatives

• A. No changes.
• B. Improve restore combo method 5.2.11.
• C. Require unspecified method in 6.7 and 8.45,
  move 3 possible methods to Annex B.
• D. Keep host detection in 6.7, move 2 alternate
  methods to Annex B.
• E. Require unspecified method in 6.7 and 8.45,
  remove alternate descriptions.