mc33690dw Freescale Semiconductor, Inc, mc33690dw Datasheet - Page 12

• Manufacturer Part Number: mc33690dw
• Description: Standalone Tag Reader Circuit Starc
• Manufacturer: Freescale Semiconductor, Inc

© Motorola, Inc., 2002.
STANDALONE CONFIGURATION WITH TWO WIRES BUS
high level on MODE2, the circuit is in
configuration B (standalone 2 wires bus
configuration, see figure 14 page 19).
The K pin is set as an output sending the
demodulated data.
The AM pin is set as a VSUP referenced input pin
receiving the amplitude modulation and the
shutdown/wake-up commands. Forcing high and
low levels on AM achieves the amplitude
modulation by switching on/off both antenna
drivers. Meanwhile, this amplitude modulation
can be monitored on the K output. This allows
antenna short and open circuit diagnosis.
The circuit can be put into standby mode by
Read & write sequences :
Entering into standby mode :
Coming out of standby mode :
When a low level is applied on MODE1 and a
AM line
K line
AM line
K line
AM line
K line
standby mode
Figure 8 : Modes access description in two wires bus configuration
t ≥ T1
data read
T1
drivers on
AM line high
Freescale Semiconductor, Inc.
Figure 9 : Configuration B state diagram
For More Information On This Product,
reset
MOTOROLA SEMICONDUCTORS PRODUCTS
T2
wake-up sequence
wake up
acknowledge
AM
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T2
switching
TD1/2
MC33690
AM line low
AM line high
standby
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forcing the AM line at zero during more than 2
ms. The circuit sends an acknowledge pulse
before entering into standby mode
In standby mode, the oscillator and most of the
internal biasing currents are switched off.
Therefore, the functions (tag reader, ISO 9141
driver) are inactive except the voltage regulator
and the ISO 9141 receiver on pin AM. The driver
output TD1 forces a low level and TD2 a high
level. A rising edge on AM wakes up the circuit.
After completion of the wake-up sequence, the
circuit is automatically set in read mode.
In configuration B, DOUT and Rx outputs always
force a low level, Tx is disabled.
drivers off
1
1
AM line low
1
1
T1 ≤ AM line low
TD1/2 off
data write modulation
AM line monitoring
data write
1
1
standby mode
data read
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revision 4.8, 5 February 2002
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