Siemens KNX EIB TP-UART 2-IC Manual page 32

GAMMA instabus
Release: February 2012
KNX EIB TP-UART 2-IC
Each L_Data-request is transmitted completely to the Host. From a L_PollData-request only the
Controlbyte is transmitted to the host if the TP-UART is a polling slave. If the TP-UART is polling
master the complete polling frame is transmitted to the host as well if a collision is detected during
sending the polling master frame.
If the 16 bit CRC calculation is enabled (see U_ActivateCRC , the host baud rate have to be 19200)
then the Linklayer service follows a 16 bit CRC (order Highbyte, Lowbyte). The timing is fix for both
supported baudrates. The high byte of the CRC is sent 6.5 Tbit after the last received octet from bus
(calculated after stopbit) and the low byte is sent immediately afterwards.
Receive from bus s 0 1 2 3 4 5 6 7 P S
Send to Controller
TPUART TXD (19200)
Fig. 27: Timing for CRC 16 bit
3.2.3.1.11 Acknowledge Services
Acknowledge services are only transmitted to the host in busmonitormode.
Note: In busmonitormode each received byte on the EIB is sent through the TP-UART-IC including
illegal control bytes and not used Immediate ACK. The TP-UART-IC is in this mode absolutely quiet on
the EIB.
The short acknowledgement frame format consists of 15 bit times idle time followed by a single
character which is used to acknowledge an L_Data.req frame. The following Figure shows the
corresponding codes of the short acknowledgement.
Fig. 28: Short Acknowledgement Frame Format
3.2.3.1.12 TP-UART-Control Services
The TP-UART-Control service exist only on this interface. They are to reset the communication or to
inform the host about the actual state.
Technical Manual
page 32
Data Checksum
s 0 1 2 3 4 5 6 7 P S
Data
! ! 2
© Siemens AG 2012
Subject to change without further notice.
Checks CRC HB CRC LB
pages 42
IACK
s 0 1 2 3 4 5 6 7 P S _ _ _ _ _ _ _ _ _ _ _
confirm
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