mc33696fje/r2 Freescale Semiconductor, Inc, mc33696fje/r2 Datasheet - Page 23

• Manufacturer Part Number: mc33696fje/r2
• Description: Mc33696 Pll Tuned Uhf Transceiver
• Manufacturer: Freescale Semiconductor, Inc

Each time is defined with the associated value found in the RXONOFF register.
The strobe oscillator is a relaxation oscillator in which an external capacitor C3 is charged by an internal
current source (see
strobe frequency is F
In receive mode, setting the STROBE pin to V
the oscillator threshold voltage, the condition on which the STROBE pin is set to V
internally, and the oscillator pulldown circuitry is disabled. This limits the current consumption. After a
strobe forced at “1”, the external driver should pass via a “0” state to discharge the capacitor before going
to high impedance state (otherwise, the ON time would last a long time after the driver release).
When the strobe oscillator is running (i.e., during an off time), forcing the STROBE pin to V
strobe clock and, therefore, maintains the circuit off.
Figure 13
15
15.1 Transmit Mode
The SPI is deselected. The MC33696 receives the telegram to transmit on the MOSI line (see
Freescale Semiconductor
(Input)
MOSI
•
•
SEB
STROBE
STROBE
On time = RON[3:0] x 512 x T
Off time = receiver OFF time = N x T
from ROFF[2:0] (see
Receiver
Counter
Counter
Status
Digital
Clock
Clock
Communication in Transmit and Receive Mode
shows the associated timings.
Off
On
Threshold
0
RON
Figure
Strobe
47). When the threshold is reached, C3 is discharged and the cycle restarts. The
= 1/T
Off
Table
Cycling Period
0
t
Strobe
Strobe
ROFF-1 ROFF
Figure 13. Receiver On/Off Sequence
Figure 14. Transfer in Transmit Mode
21).
with T
digclk
MC33696 Data Sheet, Rev. 9
(see
Strobe
Strobe
On
CCIO
Crystal Oscillator Startup
0
Table
= 10
RON
+ MIN (T
at any time forces the circuit on. As V
Data
20; begins after the crystal oscillator has started),
6
x C3.
Off
0
Strobe
Communication in Transmit and Receive Mode
/ 2, receiver On time), with N decoded
SET TO V
STROBE
RON
On
CCIO
CCIO
is detected
CCIO
GND
Figure
is above
stops the
14).
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