NCN5130 Datasheet, PDF (29/58 Pages) ON Semiconductor – Transceiver

NCN5130
DIGITAL FUNCTIONAL DESCRIPTION
The implementation of the Data Link Layer as specified in the KNX standard is divided in two parts. All functions related
to communication with the Physical Layer and most of the Data Link Layer services are inside NCN5130, the rest of the
functions and the upper communication layers are implemented into the host controller (see Figure 28).
The host controller is responsible for handling:
• Checksum
• Parity
• Addressing
• Length
The NCN5130 is responsible for handling:
• Checksum
• Parity
• Acknowledge
• Repetition
• Timing
Digital State Diagram
The digital state diagram is given in Figure 29.
The current mode of operation can be retrieved by the host controller at any time (when RESETB−pin is high) by issuing
the U_SystemStat.req service and parsing back U_SystemStat.ind service (see System Status Service, p37).
Table 10. NCN5130 DIGITAL STATES
State
Explanation
RESET
Entered after Power On Reset (POR) or in response to a U_Reset.req service issued by the host controller. In this
state NCN5130 gets initialized, all features disabled and services are ignored and not executed.
POWER−UP /
POWER−UP
STOP
Entered after Reset State or when VBUS, VFILT or Xtal are not operating correctly (operation of VBUS, VFILT and
XTAL can be verified by means of the System Status Service, p37). Communication with KNX bus is not allowed.
U_SystemStat.ind can be used to verify this state (code 00).
SYNC
NCN5130 remains in this state until it detects silence on the KNX bus for at least 40 Tbits. Although the receiver of
NCN5130 is on, no frames are transmitted to the host controller.
U_SystemStat.ind can be used to verify this state (code 01).
STOP
This state is useful for setting−up NCN5130 safely or temporarily interrupting reception from the KNX bus.
U_SystemStat.ind can be used to verify this state (code 10).
NORMAL
In this state the device is fully functional. Communication with the KNX bus is allowed.
U_SystemStat.ind can be used to verify this state (code 11).
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