TDA5235
Functional Description
data interface
RX data
Application
Controller
(µC)
TDA5235
configuration
RF interface
status & alerts
control interface
Figure 44
Logical and electrical System Interfaces of the TDA5235
2.5.1.1 Control Interface
The control interface is used in order to configure the TDA5235 after start-up or to re-
configure it during run-time, as well as to properly react on changes in the status of the
receiver in the Application Controller’s firmware. The control interface offers a bi-
directional communication link by which
•
configuration data is sent from the Application Controller to the TDA5235,
• the receiver provides status information (e.g. the status of a data reception) as
response to a request it has received from the Application Controller, and
• the TDA5235 autonomously alerts the Application Controller that a certain,
configurable event has occurred (e.g. that a packet has been received successfully).
Configuration and status information are sent via the 4-wire SPI interface as described
in Chapter 2.5.5. The configuration data determines the behavior of the receiver, which
comprises
• scheduling the inactive power-saving phases as well as the active receive phases,
• selecting the properties of the RF/IF interface configuration (e.g. carrier frequency
selection, filter settings),
• configuring the properties of the frames (e.g. wake-up patterns, Telegram Start
Identifier (TSI), and optionally specifying the position, format and content of patterns
within packets that stimulate a certain, configurable alerting behavior (Message ID)).
Note that the TDA5235 receiver IC supports reception of up to two configuration sets on
a single channel each in a time-based manner without reconfiguration. Thus, the RF/IF
interface as well as the frame format properties support alternative settings, which can
be activated autonomously by the receiver as part of the scheduling process.
In contrast to the high-level interface used for communicating configuration instructions
and status information, alerts are emitted by the receiver on a digital output pin that may
trigger external interrupts in the Application Controller. Note that the alerting conditions
as well as the polarity of the output pin are configurable, see Chapter 2.5.4.
Data Sheet
75
V1.0, 2010-02-19
INFINEON [ Infineon ]
