Diagnostic And Reset Considerations; Figure 68. Reset Error Register Values - IBM IC35L020 - Deskstar 20 GB Hard Drive Specifications

13.3 Diagnostic and Reset considerations

For each Reset and Execute Device Diagnostic the diagnostic is done as follows:
Power On Reset
DASP- is read by Device 0 to determine if Device 1 is present. If Device 1 is present, Device 0
must read PDIAG- to determine when it is valid to clear the BSY bit and whether Device 1 has
powered on or reset without error. Otherwise Device 0 clears the BSY bit whenever it is ready
to accept commands. Device 0 may assert DASP- to indicate device activity.
Hard Reset, Soft Reset
If Device 1 is present Device 0 must read PDIAG- to determine when it is valid to clear the BSY
bit and whether Device 1 has reset without any errors. Otherwise Device 0 must simply reset
and clear the BSY bit. DASP- is asserted by Device 0—and Device 1 if it is present—in order to
indicate device active.
Execute Device Diagnostic
If Device 1 is present, Device 0 must read PDIAG- to determine when it is valid to clear the
BSY bit and if Device 1 passed or failed the EXECUTE DEVICE DIAGNOSTIC command.
Otherwise Device 0 must simply execute its diagnostics and then clear the BSY bit. DASP- is
asserted by Device 0—and Device 1 if it is present—in order to indicate the device is active.
In all the above cases Power on, RESET-, Soft reset, and the EXECUTE DEVICE DIAGNOSTIC
command the Device 0 Error register as shown in the following figure.
'x' indicates the appropriate Diagnostic Code for the Power on, RESET–, Soft Reset, or
Device Diagnostic error.
Device 1 present?
Yes
Yes
Yes
Yes
No
No

Figure 68. Reset error register values

PDIAG– Asserted?
Yes
Yes
No
No
(not read)
(not read)
Deskstar 60 GXP Hard disk drive specification
77
Device 0 Passed
Yes
No
Yes
No
Yes
No
Error Register
01h
0xh
81h
8xh
01h
0xh