MC33592FTA Datasheet, PDF (15/28 Pages) Motorola, Inc – PLL Tuned UHF Receiver for Data Transfer Applications

Freescale Semiconductor, Inc.
STROBE OSCILLATOR
State 6:
Programming SOE=0 sets ROMEO2 to state 6. The circuit is in Sleep mode.
State 7:
A high level applied on STROBE sets the circuit into state 7. If an ID or its complement is detected, the state
machine advances to state 8. If not, it will stay in state 7 as long as STROBE is high.
State 8:
After ID or its complement detection, ID byte is sent to the microcontroller on MOSI line at 310kBd. This warns
the microcontroller that data are received which means that an high level has to be maintained on STROBE. At
any time a low level applied on STROBE sets the circuit into state 6.
State 9:
If Header or its complement is detected, the state machine advances to state 10. If not, it will stay in state 9 as
long as STROBE is high.
State 10:
If Header has been received, data and clock signals are output on the SPI port. If the complement of Header has
been received, output data are complemented too. At any time a low level applied on STROBE sets the circuit
into state 6, after the current byte is fully transmitted.
State 11:
If data are received after a End of Message they are output on the MOSI pin without clock recovery.
For all states:
At any time, a low level applied on RESETB for more than one Ts forces the state machine to state 1. When the
transition condition from one state to the next one is fulfilled, the transition time is one Ts except reaching state 6.
The transition time for reaching state 6 is 2 ´ Ts (+ time needed to shift out a full byte if STROBE pin is forced to
low when in state 10).
STROBE OSCILLATOR
The Strobe Oscillator is a relaxation oscillator in which an external capacitor C5 is charged by an external
resistance R2 (refer to figure 17 and table 11). When a threshold is reached or exceeded C5 is discharged and
the cycle restarts. The period is: T_Strobe=0.12 ´ R2 ´ C5.
The circuit may be forced into states 0b, 3, 7 etc. (see State Machine Diagrams) by setting the STROBE pin to
V_CC. As V_CC is above the oscillator threshold voltage referred to in the previous paragraph, the condition in which
the STROBE pin is set to V_CC is internally detected and the oscillator pull-down circuitry disabled to limit the
current which must be supplied.
MOTOROLA
MC33592 Technical Data
15
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