The
outputs are then amplitude limited and then applied to the ADC. Further signal conditioning
and processing are performed digitally in the DSP.
BP
filter
Ant
Q
I
Switch
Delay
PA
AMP
Circulator
LP
filter
LP
filter
I
Q
BP
filter
BP
filter
AMP
AMP
Modulating signal
ADC
PLL 2
PLL 1
DSP
Power
splitter
Mixer
FIGURE 5.5
Simpli?¬?ed hardware chain of the UHF module.
104 RFID Handbook: Applications, Technology, Security, and Privacy
5.2.9 Software Design
The system makes use of DSP-BIOS II from Texas Instruments. DSP-BIOS is a scalable realtime
kernel, designed speci?¬?cally for the TMS320C5000 and TMS320C6000 DSP platforms.
DSP-BIOS is an integral part of the Code Composer Studio Development Tools from TI.
The programming is done using Microsoft Visual Studio C???? and Texas Instruments??™
Code Composer Studio.
The heart of the SDLR is the TMS320C5416 DSP, which runs a TI DSP-BIOS II real-time
kernel and controls the interface in addition to the speci?¬?c transmit and receive functions.
DSP-BIOS provides a convenient multitasking capability through events, software and
hardware interrupts, which operate at various levels of priority. Other functions such as
tag management and communication to other readers or host PCs are performed in the
microcontroller.
The DSP is required to receive commands from the microcontroller, and form packets of
symbols, which are embedded into a ?¬‚exible frame in order to be recognizable by a tag.
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