User's Manual

BlueMod+S42 Hardware User Guide
1VV0301303 Rev.3 – 2016-08-22
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
Page 18 of 62
3.1.1 Power-up Slew-Rate
Parameter Min Max Unit
VSUP rise time rate
(1)
0 60 ms
(1)
0V to 1,7V
Table 2: Power up Rise Time Requirements
3.2 Reset
BlueMod+S42 are equipped with circuitry for generating reset from three sources:
• A reset is held active, when VSUP falls below the threshold of the brownout detector
(V
BOR =
1,2V … 1,7V), and is released when VSUP rises above V
BOR
+ V
HYST
.
The brownout detector also holds the reset active during power up, until VSUP >
V
BOR
.
• A reset is generated, when VSUP is > V
BOR
and increases 300 mV or more, within
300 ms or less.
• By holding pin B-1 (EXT-RES#) at ≤ VSUP*0,3V for t
HOLDRESETNORMAL
≥ 0,2µs, an
external reset (pin reset) is generated. This pin has a fixed internal pull-up resistor
(R
PU
= 11kΩ ... 16kΩ). EXT-RES# may be left open if not used.
BlueMod+S42
E-6,F-6
VSUP
GND
+3V3
EXT-RES#
B-1
Reset-Switch is optional
Please Note: EXT-RES# of BlueMod+S42 has approx. 13k internal pullup.
470R*
Reset signal is optional
Host MCU
GPIO
VDD
* resistor can be omitted,
if GPIO is open drain type
Figure 3: BlueMod+S42 Example Reset
The following table shows the pin states of BlueMod+S42 during reset active.