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2.2 Reset
The EVK-NORA-B1 provides a configurable hardware reset to the NORA-B1 module. The Reset button
can be configured to connect to an input on the interface IC or to directly connect to nRESET signal in
the module.
The reset button is connected to the debug interface chip by default. Pressing reset while the
interface IC is powered causes a momentary reset signal on the nMOD_RESET output of the interface
IC, which converted to the VSYS I/O voltage for the module. If the reset button is held down during the
EVK power on, it causes the interface IC to enter its bootloader mode, which allows programming of
the SEGGER J-Link interface.
Solder jumpers JRST1 and JRST2 allow the reset button to bypass the interface circuit and connect
directly to the nRESET signal on the module.
Figure 3: EVK schematic – reset
Signal name
IMCU_BOOT
nRESET
nMOD_RESET
nSHLD_RESET
Table 3: EVK reset signals
2.3 Buttons
The evaluation board has four user buttons that are active low and connect to ground when pressed.
Table 4
associates the button number and corresponding components.
Button
Switch
1
SW4
2
SW5
3
SW7
4
SW8
Table 4: User button components
The internal pull-up resistor of each NORA-B1 GPIO pin must be enabled for proper operation.
☞
Example programs in the SDK enable the pull-up resistors by default.
The buttons and ESD protection can be completely removed from the circuit by breaking the
associated jumper.
UBX-20030319 - R06
C1-Public
Description
Input to interface chip. During normal operation, drive low to reset the NORA-B1. Drive low during
power-up to enter bootloader mode on the interface chip.
NORA-B1 reset signal at the NORA-B1 I/O voltage.
NORA-B1 reset signal at the interface chip I/O voltage.
I/O header shield reset signal (J27, pin 3)
GPIO
Jumper
P0.23
J24
P0.24
J21
P0.08
J22
P0.09
J23
Hardware description
Protection diode
D7
D8
D11
D12
EVK-NORA-B1 - User guide
Page 9 of 31
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