MC33596_10 Datasheet, PDF (14/70 Pages) Freescale Semiconductor, Inc – PLL Tuned UHF Receiver for Data Transfer Applications

Receive Mode
STROBE ¹
0
CONFB ¹
0
*Refer to
(Section 10) ^{SEB 1}
0
SCLK 1
(Output) 0
MOSI 1
(Output) ⁰
Recovered Clock Updated to I ncoming Signal Data Rate
D7 D6 D5 D4 D3 D2 _D1 D0 D7 D6 D5 D4 D3 D2 _D1 D0 D7 D6 D5 D4 D3 D2 _D1 D0
Figure 5. Typical Transfer in Receive mode with Data Manager
11.2.1 Data Manager Functions
In receive mode, Manchester coded data can be processed internally by the data manager. After decoding,
the data is available on the digital interface, in SPI format. This minimizes the load on the MCU.
The data manager, when enabled (DME = 1), has five purposes:
• First ID detection: the received data are compared with the identifier stored in the ID register.
• Then the HEADER recognition: the received data is compared with the data stored in the
HEADER register.
• Clock recovery: the clock is recovered during reception of the preamble and is computed from the
shortest received pulse. While this signal is being received, the recovered clock is constantly
updated to the data rate of the incoming signal.
• Output data and recovered clock on digital interface: see Figure 5.
• End-of-message detection: an EOM consists of two consecutive NRZ ones or zeroes.
Table 6 details some MC33596 features versus DME values.
Table 6. the MC33596 Features versus DME
DME Digital Interface Use
0 SPI deselected, received data
are directly sent to MOSI
when CONFB = 1
1
SPI master, data sent on
MOSI with clock on SCLK
when CONFB = 1
Data Format
Bit stream
No clock
Data bytes
Recovered clock
Output
MOSI
—
MOSI
SCLK
11.2.2 Manchester Coding Description
The MC33596 data manager is able to decode Manchester-coded messages. For other codings, the data
manager should be disabled (DME=0) for raw data to be available on MOSI.
MC33596 Data Sheet, Rev. 4
14
Freescale Semiconductor