GAMMA
instabus
Release: February 2012
KNX EIB TP-UART 2-IC
Technical Manual
pages 42
Siemens AG
Infrastructure and Cities Sector,
Building Technologies
page 16
© Siemens AG 2012
Control Products and Systems
Subject to change without further notice.
P. O. Box 10 09 53,
D-93009 Regensburg
Symbol Parameter
Min
Max
Unit
Note
V
IL
voltage range for input low level
0.3 * VIF
V
IH
voltage range for input high level
0.7 * VIF
V
hyst
hysteresis for switching level
0.1 * VIF
0.4 * VIF
1)
R
PullDown
value of internal pull-down resistor
150
450
k
Ω
1) switching level approx. VIF/2, i.e. VIF/2
±
V
hyst
/2
Table 17 Interface Pin RxD
2.2.17 Interface Pin TxD
The UART interface output pin TxD transmits the information to host electronic. The high output level
is derived from external supply voltage VIF.
In normal mode: LOW pulse at EIB bus
TxD3 = HIGH
TxD = LOW
In analog mode: LOW pulse at EIB bus
TxD3 = HIGH
TxD = HIGH
Symbol Parameter
Min
Max
Unit
Note
V
OH
output voltage high
VIF - 0.5
V
I
OH
= -5 mA
V
OL
output voltage low
0.4
V
I
OL
= 5 mA
t
r,
t
f
rise time, fall time (10 %
↔
90 %)
100
ns
C
L
= 150 pF
Table 18 Interface Pin TxD
2.2.18 Switching Pin STxO
The switching pin STxO is an open drain output with an external pull-up resistance. It is driven to
provide a high output level during transmission. In all modes where the digital part is active an internal
signal generated by the digital part and used to control the switching of STxO. It switches from LOW to
HIGH before (typ. 500
µ
s) the first transmit signal. In all modes where the digital part is not active Table
19 Switching Pin STxO applies. The control for the switching of STx0 is derived from the send pulse
width limitation implemented within the analog part. The high output level is derived from an external
supply voltage.
Symbol Parameter
Min
Max
Unit
Note
V
STx0
External supply voltage for STx0
VIF
50
V
4)
V
OH
output voltage high
50
V
4) 5)
V
OL
output voltage low
0.4
V
I
OL
= 5 mA
t
DELAY
delay time from active RxD to STxO L/H (50%
↔
50%)
300
ns
1) 2)
t
SENDMAX
delay time from inactive RxD to STxO H/L (50%
↔
50%)
1.5
2
ms
3)
t
r
rise time (10 %
→
90 %)
ns
5)
t
f
fall time (90 %
→
10 %) for V
STx0
=30V
900
ns
C
L
= 150 pF
fall time (90 %
→
10 %) for V
STx0
=5.25V
100
ns
C
L
= 150 pF
1) When the digital part is not active the STxO L/H is triggered / retriggered by an active RxD signal.
2) In normal mode the Digital part controls the STxO transitions with regard to the RxD signal.
3) When the digital part is not active.
4) during surge impulse: -20 V for 2 µsec and +65 V for 150 µsec
5) I
OH
and t
r
are set be external pull-up resistance.
Table 19 Switching Pin STxO
