NCN5121 Datasheet, PDF (34/57 Pages) ON Semiconductor – Transceiver

NCN5121
Reset Service
Reset the device to the initial state.
Host Ctrl
NCN5121
U_Reset.req
0 000 0 00 1
U_Reset.ind
0 000 0 01 1
KNX Bus
Figure 31. Reset Service
Remark: U_Reset.Ind will be send when entering Normal State (see Digital State Diagram, p29).
State Service
Get internal communication state of the device.
Host Ctrl
NCN5121
U_State.req
0 000 0 01 0
KNX Bus
U_State.ind
sc re te pe tw 1 1 1
Figure 32. State Service
sc (slave collision): ‘1’ if collision is detected during transmission of polling state
re (receive error): ‘1’ if corrupted bytes were sent by the host controller. Corruption involves incorrect parity (9−bit
UART only) and stop bit of every byte as well as incorrect control octet, length or checksum of frame
for transmission.
te (transceiver error): ‘1’ if error detected during frame transmission (sending ‘0’ but receiving ‘1’).
pe (protocol error): ‘1’ if an incorrect sequence of commands sent by the host controller is detected.
tw (thermal warning): ‘1’ if thermal warning condition is detected.
Set Busy Service
Activate BUSY mode.
During this time and when autoacknowledge is active (see Set Address Service p35), NCN5121 rejects the frames whose
destination address corresponds to the stored physical address by sending the BUSY acknowledge. This service has no effect
if autoacknowledge is not active.
Host Ctrl
NCN5121
KNX Bus
U_SetBusy.req
0 000 0 01 1
Figure 33. Set Busy Service
Remark: BUSY mode is deactivated immediately if the host controller confirms a frame by sending U_Ackn.req service.
Quit Busy Service
Deactivate the BUSY mode.
Restores back to the normal autoacknowledge behavior with ACK sent on the bus in response to addressing frame (only if
autoacknowledge is active). This service has no effect if autoacknowledge is not active or BUSY mode was not set.
Host Ctrl
NCN5121
KNX Bus
U_QuitBusy.req
0 000 0 10 0
Figure 34. Quit Busy Service
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