Tx_ctrl signal for tx burst indication, Features, Tx_ctrl frequency and duration – Sierra Wireless AIRPRIME WISMO218 User Manual
Page 72: Figure 36, Tx_ctrl state during tx burst, Table 33, Tx_ctrl status, Table 34, Electrical characteristics of the signal
WA_DEV_W218_PTS_002
Rev 006
April 29, 2010
72
Product Technical Specification &
Customer Design Guidelines
Interfaces
3.17. TX_CTRL Signal for TX Burst Indication
3.17.1. Features
The TX_CTRL signal is a 2.8V indication signal for TX Burst with a 100K
pull-up resistor
implemented inside the AirPrime WISMO218 embedded module.
Table 33: TX_CTRL Status
AirPrime WISMO218 State
TX_CTRL Status
During TX burst
Low
No TX
High
During TX burst, there will be higher current drain from the VBATT power supply which causes a
voltage drop. This voltage drop from VBATT is a good indication of a high current drain situation
during TX burst.
The blinking frequency is about 216Hz.
The output logic low duration, T
duration
, depends on the number of TX slots and is computed as follows:
T
duration
= T
advance
+ (0.577ms x number of TX slots) + T
delay
.
Figure 36.
TX_CTRL State During TX Burst
Table 34: Electrical Characteristics of the Signal
Parameter
Condition
Minimum
Typ.
Maximum
Unit
V
OH
2.6
-
2.95
V
V
OL
-
-
0.4
V
T
advance
@500mA
-
18
-
µs
@1A
-
27
-
µs
T
delay
-
11
-
µs