Datasheet

EVTMG3 Command (09h)
The EVTMG3 command initiates the event timing mode
3 advanced automatic measurement feature. This timing
mode performs automatic temperature measurements
as described in the Event Timing Operation section. The
duration of the automatic measurements depends upon
the settings in the Event Timing 1 register, Event timing 2
register, CONT_INT and ET_CONT bits in the Calibration
and Control register.
HALT Command (0Ah)
The HALT command is sent to the MAX35101 to stop any
of the three EVTMG1/2/3 commands. All register data
content is frozen and the SPI is then made available for
access by the host microcontroller for commands, mem-
ory access, and register access. The HALT command
takes time to execute. Since the EVTMGx commands are
comprised of multiple TOF_DIFF and Temperature com-
mands, the HALT command causes the MAX35101 to
evaluate its own state and complete the currently execut-
ing TOF_DIFF or temperature command. Once the HALT
command has completed, all registers update and the
MAX35101 sets the halt bit in the Interrupt Status regis-
ter and then asserts the INT device pin (if enabled). The
host microprocessor reads the Interrupt Status register to
determine the interrupt source.
LDO_Timed Command (0Bh)
To access the flash memory, the internal low-dropout
voltage regulator that powers the flash circuitry must be
enabled. By sending the LDO_Timed command to the
MAX35101 prior to the desired flash access command
(read, write, block erase), the internal regulator is enabled
and powers the flash circuitry. The LDO bit is set in the
Interrupt Status register and the INT device pin asserts
(if enabled) when the internal regulator has been turned
on and is stable which takes approximately t
STABLE
. The
host microprocessor, upon detection of the asserted INT
device pin, should read the Interrupt Status register LDO
bit to determine that the internal regulator is stable and
the flash is now ready to be accessed. The internal regu-
lator remains enabled for a continuous period until the CE
device pin is deasserted after any flash command (read,
write, block erase). The LDO_Timed command is used in
place of the LDO_ON command when a data access to
the flash is required in a short burst. This minimizes SPI
access since the LDO_OFF command is not required to
be sent to the MAX35101 to turn off the internal regulator.
LDO_ON Command (0Ch)
To access the flash memory, the internal low-dropout
voltage regulator that powers the flash circuitry must
be enabled. By sending the LDO_ON command to the
MAX35101 prior to the desired flash access command
(read, write, block erase), the internal regulator is enabled
and powers the flash circuitry. The LDO bit is set in the
Interrupt Status register and the INT device pin asserts
(if enabled) when the internal regulator has been turned
on and is stable which takes approximately t
STABLE
.
The host microprocessor, upon detection of the asserted
INT device pin, should read the Interrupt Status register
LDO bit to determine that the internal regulator is stable
and the flash is now ready to be accessed. The internal
regulator remains enabled for a continuous period until
the LDO_OFF command is received by the MAX35101.
The LDO_ON command is generally used when the host
microprocessor needs to perform multiple-word writes to
the MAX35101 since multiple-word writes require that
the CE device pin be toggled after every word of data
written. The LDO_ON command prevents the LDO from
automatically disabling itself after each transition of the
CE device pin.
LDO_OFF Command (0Dh)
To access the flash memory, the internal low-dropout
voltage regulator that powers the flash circuitry must
be enabled. By sending the LDO_OFF command to the
MAX35101, the internal regulator is disabled and the
Interrupt Status register LDO bit is cleared. The INT
device pin is not asserted. The LDO_OFF command is
used in conjunction with the LDO_ON command.
Calibrate Command (0Eh)
The calibrate command performs the calibration routine
as described in the calibration operation section. When
the calibrate command has completed the measurement,
the Calibration Results register contains the measured
32kHz period measuremnt value, the MAX35101 sets
the calibration bit in the Interrupt Status register and then
asserts the INT device pin (if enabled). The host micro-
processor reads the Interrupt Status register to determine
the interrupt source and then read the Calibration Results
register to be able to calculate the 4MHz ceramic oscilla-
tor gain factor.
MAX35101 Time-to-Digital Converter with Analog Front-End
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