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Annex A: Diagnostic and Reset Considerations
(informative).
This annex describes the following timing relationships during:
a) Power On and Hardware Resets
- One drive
- Two drives
b) Software Reset
- One drive
- Two drives
c) Diagnostic Command Execution
- One drive
- Two drives
- Two drives - Drive\ f1 failed
The timing assumes the following:
o DASP- is asserted by Drive\ f1 and received by Drive\ f0 at power-on or
hardware reset to indicate the presence of Drive\ f1. At all other times it
is asserted by Drive\ f0 and Drive\ f1 to indicate when a drive is active.
o PDIAG- is asserted by Drive\ f1 and detected by Drive\ f0. It is used by
Drive\ f1 to indicate to Drive\ f0 that it has completed diagnostics and is
ready to accept commands from the Host (BSY bit is cleared). This does not
indicate that the drive is ready, only that it can accept commands. This
line may remain asserted until the next reset occurs or an Execute
Diagnostic command is received.
o Unless indicated otherwise, all times are relative to the event that
triggers the operation (RESET-, SRST=1, Execute Diagnostic Command).
A.1 Power On and Hardware Resets
A.1.1 Power On and Hardware Resets - One Drive\ f
- Host asserts RESET- for a minimum of 25 usec.
- Drive\ f0 sets BSY within 400 nsecs after RESET- is negated.
- Drive\ f0 negates DASP- within 1 msec after RESET- negated.
- Drive\ f0 performs hardware initialization
- Drive\ f0 may revert to its default condition
- Drive\ f0 waits 1 msec then samples for at least 450 msec for DASP- to be
asserted from Drive\ f1.
- Drive\ f0 clears BSY when ready to accept commands (within 31 seconds).
A.1.2 Power On and Hardware Resets - Two Drives
- Host asserts RESET- for a minimum of 25 usec.
- Drive\ f0 and Drive\ f1 set BSY within 400 nsec after RESET- negated.
- DASP- is negated within 1 msec after RESET- is negated.
A.1.2.1 Drive\ f1
- Drive\ f1 negates PDIAG- before asserting DASP-.
- Drive\ f1 asserts DASP- within 400 msecs after RESET- (to show presence).
- Drive\ f1 performs hardware initialization and executes its internal
diagnostics.
- Drive\ f1 may revert to its default condition
- Drive\ f1 posts diagnostic results to the Error Register
- Drive\ f1 clears BSY when ready to accept commands.
- Drive\ f1 asserts PDIAG- to indicate that it is ready to accept commands
(within 30 seconds from RESET-).
- Drive\ f1 negates DASP- after the first command is received or negates DASP-
if no command is received within 30 seconds after RESET-.
A.1.2.2 Drive\ f0
- Drive\ f0 performs hardware initialization and executes its internal
diagnostics.
- Drive\ f0 may revert to its default condition
- Drive\ f0 posts diagnostic results to the Error Register
- After 1 msec, Drive\ f0 waits at least 450 msec for DASP- to be asserted
(from Drive\ f1). If DASP- is not asserted, no Drive\ f1 is present (see POWER-
ON RESET - One Drive\ foperation).
- Drive\ f0 waits up to 31 seconds for Drive\ f1 to assert PDIAG-. If PDIAG- is
not asserted, Drive\ f0 sets Bit\ f7=1 in the Error Register.
- Drive\ f0 clears BSY when ready to accept commands (within 31 seconds).
A.2 Software Reset
A.2.1 Software Reset - One Drive\ f
- Host sets SRST=1 in the Device Control Register.
.. - Drive\ f0 waits for SRST to be cleared by Host.
.. - Drive\ f0 sets BSY within 400 nsec after SRST=0.
- Drive\ f0 sets BSY within 400 nsec after detecting that SRST=1.
- Drive\ f0 performs hardware initialization and executes its internal
diagnostics.
- Drive\ f0 may revert to its default condition.
- Drive\ f0 posts diagnostic results to the Error Register.
- Drive\ f0 clears BSY when ready to accept commands (within 31 seconds).
A.2.2 Software Reset - Two Drives
- Host sets SRST=1 in the Device Control Register.
.. - Drives wait for host to clear SRST.
.. - Drive\ f0 and Drive\ f1 set BSY within 400 nsec after SRST=0.
- Drive\ f0 and Drive\ f1 set BSY within 400 nsec after detecting that SRST=1.
- Drive\ f0 and Drive\ f1 perform hardware initialization.
- Drive\ f0 and Drive\ f1 may revert to their default condition.
A.2.2.1 Drive\ f1
- Drive\ f1 negates PDIAG- within 1 msec.
- Drive\ f1 clears BSY when ready to accept commands.
- Drive\ f1 asserts PDIAG- to indicate that it is ready to accept commands
(within 30 seconds).
A.2.2.2 Drive\ f0
- Drive\ f0 waits up to 31 seconds for Drive\ f1 to assert PDIAG-.
- Drive\ f0 clears BSY when ready to accept commands (within 31 seconds).
A.3 Diagnostic Command Execution
A.3.1 Diagnostic Command Execution - One Drive\ f(Passed)
- Drive\ f0 sets BSY within 400 nsec after the Execute Diagnostic command was
received.
- Drive\ f0 performs hardware initialization and internal diagnostics.
- Drive\ f0 resets Command Block registers to default condition.
- Drive\ f0 posts diagnostic results to the Error Register
- Drive\ f0 clears BSY when ready to accept commands (within 6 seconds).
A.3.2 Diagnostic Command - Two Drives (Passed)
- Drive\ f0 and Drive\ f1 set BSY within 400 nsec after the Execute Diagnostic
command was received.
A.3.2.1 Drive\ f1
- Drive\ f1 negates PDIAG- within 1 msec after command received.
- Drive\ f1 performs hardware initialization and internal diagnostics.
- Drive\ f1 resets the Command Block registers to their default condition.
- Drive\ f1 posts diagnostic results to the Error Register
- Drive\ f1 clears BSY when ready to accept commands.
- Drive\ f1 asserts PDIAG- to indicate that it is ready to accept commands
(within 5 seconds).
A.3.2.2 Drive\ f0
- Drive\ f0 performs hardware initialization and internal diagnostics.
- Drive\ f0 resets the Command Block registers to their default condition.
- Drive\ f0 waits up to <5 seconds for Drive\ f1 to assert PDIAG-.
- Drive\ f0 posts diagnostic results to the Error Register
- Drive\ f0 clears BSY when ready to accept commands (within 6 seconds).
A.3.3 Diagnostic Command Execution - One Drive\ f(Failed)
- Drive\ f0 sets BSY within 400 nsec after Diagnostic command received.
- Drive\ f0 performs hardware initialization and internal diagnostics.
- Drive\ f0 resets Command Block registers to default condition.
- Drive\ f0 posts a Diagnostic Code to the Error Register indicating a failure.
- Drive\ f0 clears BSY when ready to accept commands (within 6 seconds)
A.3.4 Diagnostic Command Execution - Two Drives (Drive\ f1 Failed)
- Drive\ f0 and Drive\ f1 set BSY within 400 nsec after Diagnostic command
received.
A.3.4.1 Drive\ f1
- Drive\ f1 negates PDIAG- within 1 msec after command received.
- Drive\ f1 performs hardware initialization and internal diagnostics.
- Drive\ f1 resets the Command Block registers to their default condition.
- Drive\ f1 posts a Diagnostic Code to the Error Register indicating failure.
- Drive\ f1 clears BSY.
- Drive\ f1 does not assert PDIAG-, indicating that it failed diagnostics.
A.3.4.2 Drive\ f0
- Drive\ f0 performs hardware initialization and internal diagnostics.
- Drive\ f0 resets the Command Block registers to their default condition.
- Drive\ f0 waits 6 seconds for Drive\ f1 to assert PDIAG- but PDIAG- is not
asserted by Drive\ f1.
- Drive\ f0 posts a Diagnostic Code to the Error Register setting Bit\ f7=1 to
indicate that Drive\ f1 failed diagnostics.
- Drive\ f0 clears BSY when ready to accept commands (within 6 seconds).
..rm102
NOTE: The 6 seconds referenced above is a host-oriented value.
Annex B: Diagnostic and Reset Considerations
(informative).
B.1 Power on and hardware reset (RESET-)
DASP- is read by Drive\ f0 to determine if Drive\ f1 is present. If Drive\ f1 is
present Drive\ f0 will read PDIAG- to determine when it is valid to clear BSY
and whether Drive\ f1 has powered on or reset without error, otherwise Drive\ f0
clears BSY whenever it is ready to accept commands. Drive 0 may assert DASP-
to indicate drive activity.
B.2 Software reset
If Drive\ f1 is present Drive\ f0 will read PDIAG- to determine when it is valid
to clear BSY and whether Drive\ f1 has reset without any errors, otherwise
Drive\ f 0 will simply reset and clear BSY. DASP- is asserted by Drive\ f0 (and
Drive\ f1 if it is present) in order to indicate drive active.
B.3 Drive\ fDiagnostic Command
If Drive\ f1 is present, Drive\ f0 will read PDIAG- to determine when it is valid
to clear BSY and if Drive\ f1 passed or failed the Execute Drive\ fDiagnostic
command, otherwise Drive\ f0 will simply execute its diagnostics and then clear
BSY. DASP- is asserted by Drive\ f0 (and Drive\ f1 if it is present) in order to
indicate the drive is active.
B.4 Truth Table
In all the above cases: Power on, RESET-, software reset, and the Execute
Drive\ fDiagnostics command the Drive\ f0 Error Register is calculated as follows:
Drive\ f1 PDIAG- Drive\ f0 Error
Present? Asserted? Passed Register
Yes Yes Yes 01h
Yes Yes No 0xh
Yes No Yes 81h
Yes No No 8xh
No (not read) Yes 01h
No (not read) No 0xh
Where x indicates the appropriate Diagnostic Code for the Power on, RESET-,
software reset, or drive\ fdiagnostics error.
B.5 Power On or Hardware Reset Algorithm
1) Power on or hardware reset
2) The hardware should automatically do the following:
a) Set up the hardware to post both Drive\ f0 and Drive\ f1 status
b) Set the Drive\ f0 Status Register to 80h (set BSY and clear
all the other status bits)
c) Set the Drive\ f1 Status Register to 80h (set BSY and clear all
the other status bits)
3) Read the single Drive\ f0/Drive\ f1 jumper and note its state
4) Perform any remaining time critical hardware initialization including
starting the spin up of the disk if needed
5) If Drive\ f1
a) Negate the PDIAG- signal
b) Set up PDIAG- as an output
c) Assert the DASP- output
d) Set up DASP- as an output if necessary
e) Set up the hardware so it posts Drive\ f1 status only and
continue to post 80h for Drive\ f1 status
NOTE: all this must happen within 400 msec after power on or RESET-
If Drive\ f0
a) Set up PDIAG- as an input
b) Release DASP- and set up DASP- as an input
c) Test DASP- for 450 msec or until DASP- is asserted by Drive\ f1
d) If DASP- is asserted within 450 msec
i) Note that Drive\ f1 is present
ii) Set up the hardware so it posts Drive\ f0 status only
and continue to post 80h for the Drive\ f0 status
If DASP- is not asserted within 450 msec
i) note that Drive\ f1 is not present
e) Assert DASP- to indicate drive activity
6) Complete all the hardware initialization needed to get the drive ready,
including:
a) Set the Sector Count Register to 01h
b) Set the Sector Number Register to 01h
c) Set the Cylinder Low Register to 00h
d) Set the Cylinder High Register to 00h
e) Set the Drive/Head Register to 00h
7) If Drive\ f1 and power on, or RESET- is valid
a) Set the Error Register to Diagnostic Code 01h
b) Set the Drive\ f1 Status Register to 00h
c) Assert PDIAG-
NOTE: All this must happen within 5 seconds of power on or the
negation of RESET-
If Drive\ f1 and power on or RESET- bad
a) Set the Error Register to the appropriate Diagnostic Code
b) Set the Drive\ f1 Status Register to 00h
NOTE: All this must happen within 5 seconds of power on or the
negation of RESET-
If Drive\ f0, power on or RESET- valid, and a Drive\ f1 is present
a) Test PDIAG- for 6 seconds or until PDIAG- is asserted by Drive\ f1
b) If PDIAG- is asserted within 6 seconds
i) Set the Error Register to Diagnostic Code 01h
c) If PDIAG- is not asserted within 6 seconds
i) Set the Error Register to 81h
d) Set the Drive\ f0 Status Register to 00h
If Drive\ f0, power on or RESET- bad, and a Drive\ f1 is present
a) Test PDIAG- for 6 seconds or until PDIAG- is asserted by
Drive\ f1
b) If PDIAG- is asserted within 6 seconds
i) Set the Error Register to the appropriate Diagnostic Code
c) If PDIAG- is not asserted within 6 seconds
i) Set the Error Register to 80h + the appropriate code
d) Set the Drive\ f0 Status Register to 00h
If Drive\ f0, power on or RESET- valid, and no Drive\ f1 is present
a) Set the Error Register to Diagnostic Code 01h
b) Set the Drive\ f1 Status Register to 00h
c) Set the Drive\ f0 Status Register to 00h
If Drive\ f0, power on or RESET- bad, and no Drive\ f1 is present
a) Set the Error Register to the appropriate Diagnostic Code
b) Set the Drive\ f1 Status Register to 00h
c) Set the Drive\ f0 Status Register to 00h
8) Finish spin up if needed
9) If Drive\ f1
a) Set the Drive\ f1 Status Register to 50h
b) Negate DASP- if a command is not received within 30 seconds
If Drive\ f0 and a Drive\ f1 is present
a) Set the Drive\ f0 Status Register to 50h
b) Negate DASP-
If Drive\ f0 and no Drive\ f1 is present
a) Leave the Drive\ f1 Status Register 00h
b) Set the Drive\ f0 Status Register to 50h
c) Negate DASP-
B.6 Software Reset Algorithm
1) The software reset bit is set
2) If Drive\ f1
a) The hardware should set BUSY in the Drive\ f1 Status Register
b) Negate the PDIAG- signal
NOTE: this must happen within 1 msec of the software reset
If Drive\ f0 and Drive\ f1 is present
a) The hardware should set BUSY in the Drive\ f0 Status Register
If Drive\ f0 and there is no Drive\ f1 the hardware should:
a) Set BUSY in the Drive\ f0 Status Register
b) Set the Drive\ f1 Status Register to 80h
3) Assert DASP-
4) Finish all the hardware initialization needed to place the drive in reset
5) Wait for the software reset bit to clear
6) Finish all hardware initialization needed to get the drive ready
to receive any type of command from the host including:
a) Set the Sector Count Register to 01h
b) Set the Sector Number Register to 01h
c) Set the Cylinder Low Register to 00h
d) Set the Cylinder High Register to 00h
e) Set the Drive/Head Register to 00h
7) If Drive\ f1 and reset valid
a) Set the Error Register to Diagnostic Code 01h
b) Set the Drive\ f1 Status Register to 50h
c) Assert PDIAG-
NOTE: All this must happen within 5 seconds of the clearing of
the software reset bit
If Drive\ f1 and reset bad
a) Set the Error Register to the appropriate Diagnostic Code
b) Set the Drive\ f1 Status Register to 50h
NOTE: All this must happen within 5 seconds of the clearing of
the software reset bit
If Drive\ f0, reset valid, and a Drive\ f1 is present
a) Test PDIAG- for 6 seconds or until PDIAG- is asserted by
Drive\ f1
b) If PDIAG- is asserted within 6 seconds
i) Set the Error Register to Diagnostic Code 01h
c) If PDIAG- is not asserted within 6 seconds
i) Set the Error Register to 81h
d) Set the Drive\ f0 Status Register to 50h
If Drive\ f0, reset bad, and a Drive\ f1 is present
a) Test PDIAG- for 31 seconds or until PDIAG- is asserted by
Drive\ f1
b) If PDIAG- is asserted within 31 seconds
i) Set the Error Register to the appropriate Diagnostic Code
c) If PDIAG- is not asserted within 31 seconds
i) Set the Error Register to 80h + the appropriate code
d) Set the Drive\ f0 Status Register to 50h
If Drive\ f0, reset valid, and no Drive\ f1 is present
a) Set the Error Register to Diagnostic Code 01h
b) Set the Drive\ f1 Status Register to 00h
c) Set the Drive\ f0 Status Register to 50h
If Drive\ f0, reset bad, and no Drive\ f1 is present
a) Set the Error Register to the appropriate Diagnostic Code
b) Set the Drive\ f1 Status Register to 00h
c) Set the Drive\ f0 Status Register to 50h
B.7 Diagnostic Command Algorithm
1) The diagnostics command is received
2) If Drive\ f1
a) The hardware should set BUSY in the Drive\ f1 Status Register
b) Negate the PDIAG- signal
NOTE: this must happen within 1 msec after command acceptance
If Drive\ f0 and Drive\ f1 is present
a) The hardware should set BUSY in the Drive\ f0 Status Register
If Drive\ f0 and there is no Drive\ f1 the hardware should
a) Set BUSY in the Drive\ f0 Status Register
b) Set BUSY in the Drive\ f1 Status Register
3) Assert DASP-
4) Perform all the drive diagnostics and note their results
5) Finish all the hardware initialization needed to get the drive ready
to receive any type of command from the host including:
a) Set the Sector Count Register to 01h
b) Set the Sector Number Register to 01h
c) Set the Cylinder Low Register to 00h
d) Set the Cylinder High Register to 00h
e) Set the Drive/Head Register to 00h
6) If Drive\ f1 and passed
a) Set the Error Register to Diagnostic Code 01h
b) Set the Drive\ f1 status to 50h
c) Assert PDIAG-
NOTE: All this must happen within 5 seconds of the acceptance
of the diagnostic command
If Drive\ f1 and did not pass
a) Set the Error Register to the appropriate Diagnostic Code
b) Set the Drive\ f1 status to 50h
NOTE: All this must happen within 5 seconds of the acceptance
of the diagnostic command
If Drive\ f0, passed, and a Drive\ f1 is present
a) Test PDIAG- for 6 seconds or until PDIAG- is asserted by
Drive\ f1
b) If PDIAG- is asserted within 6 seconds
i) Set the Error Register to Diagnostic Code 01h
c) If PDIAG- is not asserted within 6 seconds
i) Set the Error Register to 81h
d) Set the Drive\ f0 status to 50h
e) Issue interrupt to the host
If Drive\ f0, did not pass, and a Drive\ f1 is present
a) Test PDIAG- for 6 seconds or until PDIAG- is asserted by Drive\ f1
b) If PDIAG- is asserted within 6 seconds
i) Set the Error Register to the appropriate Diagnostic Code
c) If PDIAG- is not asserted within seconds
i) Set the Error Register to 80h + the appropriate code
d) Set the Drive\ f0 Status Register to 50h
e) Issue interrupt to the host
If Drive\ f0, passed, and no Drive\ f1 is present
a) Set the Error Register to Diagnostic Code 01h
b) Set the Drive\ f1 Status Register to 00h
c) Set the Drive\ f0 Status Register to 50h
d) Issue interrupt to the host
If Drive\ f0, did not pass, and no Drive\ f1 is present
a) Set the Error Register to the appropriate Diagnostic Code
b) Set the Drive\ f1 Status Register to 00h
c) Set the Drive\ f0 Status Register to 50h
d) Issue interrupt to the host
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.