Sequencing Engine; Overview; Warnings; Smbus Jump (Unconditional Jump) - Analog Devices ADM1063 Manual

SEQUENCING ENGINE

OVERVIEW

The ADM1063 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 10 input pins,
VP1 to VP4, VH, and VX1 to VX5.
•
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 10 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.
Table 6. Sample Sequence State Entries
State Sequence
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.
DIS3V3 If VX1 is high, go to state IDLE1.
EN2V5 If VP3 is okay, go to state PWRGD.
DIS2V5 If VX1 is high, go to state IDLE1.
FSEL1 If VP3 is not okay, go to state DIS2V5.
FSEL2 If VP2 is not okay, go to state DIS3V3.
PWRGD If VX1 is high, go to state DIS2V5.
The ADM1063 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 detect a warning
on VP1 to VP4 and VH. The warnings are OR' e d together and
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 where this might be used 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, which provide an exit from each state.
Timeout
If VP2 is not okay after 10 ms, go to
state DIS3V3.
If VP3 is not okay after 20 ms, go to
state DIS2V5.
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MONITOR
STATE
FAULT
TIMEOUT
SEQUENCE
Figure 26. State Cell
Monitor
If VP1 is not okay, go to state IDLE1.
If VP1 or VP2 is not okay, go to state FSEL2.
If VP1 or VP2 is not okay, go to state FSEL2.
If VP1 is not okay, go to state IDLE1.
If VP1, VP2, or VP3 is not okay, go to state
FSEL1.
ADM1063