Datasheet

Event Timing Mode 1
The EVTMG1 command execution causes the TOF_DIFF
command and the temperature command to be executed
automatically with programmable repetition rates and pro-
grammable total counts. In essence, both the EVTMG2
and EVTMG3 commands are simultaneously executed in
a synchronous manner.
Setting up the TOF measurements for automatic execu-
tion in event timing mode 1 is identical to setting these up
for execution with event timing mode 2. Likewise, setting
up the temperature measurements is identical to setting
these up for execution using event timing mode 3.
If the TOF_DIF command repetition rate and the tempera-
ture command repetition rate cause both measurements
to be required at the same time, the TOFF_DIF command
takes precedent. Upon completion of the TOFF_DIFF
command, the pending temperature command is execut-
ed (Figure 12).
Once all of the TOF_DIFF measurements in the sequence
are complete, the TOF_EVTMG bit in the Interrupt Status
register is set and the INT pin asserts (if enabled).
Likewise, when all of the temperature measurements in
the sequence are completed, the Temp_EVTMG bit in
the Interrupt Status register is set and the INT pin asserts
(if enabled). It should be noted that depending upon the
selected rates and number of cycles, the TOF_DIFF and
temperature measurements can complete their sequenc-
es at different times. This causes the INT pin to assert (if
enabled) before both sequences are complete.
Figure 11. EVTMG1 Pseudo Code
HOST MICROCONTROLLER USE OF EVTMG1
TIME OF FLIGHT / TEMPERATURE EVENT
PROGRAM TOF
DIFFERENCE
MEASUREMENT
FREQUENCY
(TDF3-TDF0)
(EG. EVERY 2 SECONDS)
PROGRAM NUMBER OF TOF
DIFFERENCE
MEASUREMENTS
(TDM4-TDM0) TO BE TAKEN
(EG. 2)
CONFIGURE REMAINING
MAX35101 REGISTERS
INCLUDING THE CONT_
INT
AND ET_CONT BITS
SEND THE EVTMG3
COMMAND
WAIT FOR ASSERTION OF
INT DEVICE PIN
READ INTERRUPT STATUS
REGISTER
IS TEMP_EVTMG
BIT SET?
READ THE TXINT, TXFRAC,
TX_AVGINT, TX_AVGFRAC
REGISTERS FOR
TEMPERATURE DATA
IS THE ET_CONT
BIT SET?
NO
PROGRAMMABLE IN
0.5 SECOND STEPS
UP TO 8
SECONDS
YES
UP TO 32
MEASUREMENTS CAN
BE TAKEN
AVERAGE OF TWO
TEMPERATURE
MEASUREMENTS ARE
READY FOR THE
HOST
MICROCONTROLLER
OTHER
PROCESS
NO
YES
PROGRAM TEMPERATURE
MEASUREMENT
FREQUENCY (TMF5-TMF0)
(EG. EVERY 15 SECONDS
)
PROGRAMMABLE IN
1 SECOND STEPS
UP TO 64 SECONDS
PROGRAM
# OF
TEMPERATURE
MEASUREMENTS
(TMM4-TMM0) TO BE TAKEN
(EG. 2)
UP TO 32
MEASUREMENTS CAN
BE TAKEN
IS TEMP_EVTMG
BIT SET?
AVERAGE OF 15 TOF
DIFFERENCE
MEASUREMENTS ARE
READY FOR THE HOST
MICROCONTROLLER
READ TOF_DIFF_AVG,
TOF_DIFF, AVGUP,
AVGDN, HITX REGISTERS
FOR TOF DATA
Figure 11
MAX35101 Time-to-Digital Converter with Analog Front-End
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