mc33596 Freescale Semiconductor, Inc, mc33596 Datasheet - Page 23

• Manufacturer Part Number: mc33596
• Description: Pll Tuned Uhf Receiver For Data Transfer Applications
• Manufacturer: Freescale Semiconductor, Inc

14
14.1 Receive Mode
The MC33596 is master and drives the digital interface in one of two ways, depending on the selection of
the data manager.
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15.1 Module Description
In receive mode, a received signal strength indicator can be activated by setting bit RSSIE.
The input signal is measured at two different points in the receiver chain by two different means, as
follows.
Therefore, the logarithmic amplifier provides information relative to the in-band signal, whereas the LNA
AGC voltage senses the input signal over a wider band.
The RSSI information given by the logarithmic amplifier is available in:
Freescale Semiconductor
(Output)
(Output)
SCLK
MOSI
1. DME = 1: The data manager is enabled. The SPI is master. The MC33596 sends the recovered
2. DME = 0: The data manager is disabled. The SPI is deselected. Raw data are sent directly on the
•
•
•
•
SEB
clock on SCLK and the received data on the MOSI line. Data are valid on falling edges of SCLK.
If an entire number of bytes is received, the data manager may add an extra byte. The content of
this extra byte is random. If the data received do not fill an entire number of bytes, the data manager
will fill the last byte randomly.
MOSI line, while SCLK remains at the low level.
At the IF filter output, a progressive compression logarithmic amplifier measures the input signal,
ranging from the sensitivity level up to –50 dBm.
At the LNA output, the LNA AGC control voltage is used to monitor input signals in the range
–50 dBm to –20 dBm.
Analog form on pin RSSIOUT
Digital form in the four least significant bits of the status register RSSI
Communication in Receive Mode
Received Signal Strength Indicator (RSSI)
D7 D6 D5 D4
Recovered Clock Updated to Incoming Signal Data Rate
Figure 14. Typical Transfer in Receive Mode with Data Manager
D3
D2
Figure 14
D1
MC33596 Data Sheet, Rev. 3
D0
shows a typical transfer.
D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
Communication in Receive Mode
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