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T13 E00164R0 Cable Detection Issues in D1410R1 Kent H. Pryor Quantum Corporation December 8, 2000 E00164R0
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T13 E00164R0 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.
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T13 E00164R0 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.
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T13 E00164R0 Cable Detection Discussion Goals View side-by-side summary of methods. Consensus on overall strategy. Direction for any needed proposals.
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T13 E00164R0 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.
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T13 E00164R0 D1410R1 specifications for host
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T13 E00164R0 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.
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