Datasheet

ADM1069
Rev. C | Page 17 of 32
SEQUENCING ENGINE
OVERVIEW
The ADM1069 sequencing engine (SE) provides the user with
powerful and flexible control of sequencing. The SE implements
a state machine control of the PDO outputs, with state changes
conditional on input events. SE programs can enable complex
control of boards such as power-up and power-down sequence
control, fault event handling, interrupt generation on warnings,
and so on. A watchdog function that verifies the continued
operation of a processor clock can be integrated into the SE
program. The SE can also be controlled via the SMBus, giving
software or firmware control of the board sequencing.
The SE state machine comprises 63 state cells. Each state has the
following attributes:
• Monitors signals indicating the status of the eight input
pins, VP1 to VP3, VH, and VX1 to VX4.
• Can be entered from any other state.
• Three exit routes move the state machine onto a next state:
sequence detection, fault monitoring, and timeout.
• Delay timers for the sequence and timeout blocks can be
programmed independently, and changed with each state
change. The range of timeouts is from 0 ms to 400 ms.
• Output condition of the eight PDO pins is defined and
fixed within a state.
• Transition from one state to the next is made in less than
20 μs, which is the time needed to download a state
definition from EEPROM to the SE.
04735-029
SEQUENCE
TIMEOUT
MONITOR
FAULT
STATE
Figure 26. State Cell
The ADM1069 offers up to 63 state definitions. The signals
monitored to indicate the status of the input pins are the
outputs of the SFDs.
WARNINGS
The SE also monitors warnings. These warnings can be generated
when the ADC readings violate their limit register value or when
the secondary voltage monitors on VPx and VH are triggered.
The warnings are OR’ed together and are available as a single
warning input to each of the three blocks that enable exiting
a state.
SMBus JUMP (UNCONDITIONAL JUMP)
The SE can be forced to advance to the next state uncondition-
ally. This enables the user to force the SE to advance. Examples
of the use of this feature include moving to a margining state or
debugging a sequence. The SMBus jump or go-to command can
be seen as another input to sequence and timeout blocks to
provide an exit from each state.
Table 7. Sample Sequence State Entries
State Sequence Timeout Monitor
IDLE1 If VX1 is low, go to State IDLE2.
IDLE2 If VP1 is okay, go to State EN3V3.
EN3V3 If VP2 is okay, go to State EN2V5.
If VP2 is not okay after 10 ms,
go to State DIS3V3.
If VP1 is not okay, go to State IDLE1.
DIS3V3 If VX1 is high, go to State IDLE1.
EN2V5 If VP3 is okay, go to State PWRGD.
If VP3 is not okay after 20 ms,
go to State DIS2V5.
If VP1 or VP2 is not okay, go to State FSEL2.
DIS2V5 If VX1 is high, go to State IDLE1.
FSEL1 If VP3 is not okay, go to State DIS2V5. If VP1 or VP2 is not okay, go to State FSEL2.
FSEL2 If VP2 is not okay, go to State DIS3V3. If VP1 is not okay, go to State IDLE1.
PWRGD If VX1 is high, go to State DIS2V5. If VP1, VP2, or VP3 is not okay, go to State FSEL1.