EVK-ANNA-B112 - User Guide
UBX-18018539 - R01
Product description
Page 10 of 29
Connector
annotation
Add jumper
to pins
Description
J7
7, 8
Selects the board regulated 3.3 V net as source for the VDD_ANNA net.
9, 10
Powers up the Interface MCU, USB hub, and UART to USB converter with 3.3 V.
J22
1, 3
Powers up the ANNA module. The ANNA VCC and VCC_IO pins are connected to the selected
source for the VDD_ANNA net.
2, 4
Powers up the peripherals directly connected to ANNA such as LEDs and external memory
with the ANNA supply voltage.
Table 3: Jumper positions for default power configuration
1.6.3
Battery powered, 3 V
When using a battery, Figure 9 shows the default configuration. The battery voltage is connected to
VDD_ANNA, which in turn, is connected to the ANNA-B112 VCC supply. If needed, a jumper can be
added to J22 pins 2 and 4 to supply LEDs and other peripherals with power, as long as this does not
exceed the maximum current rating of the battery. If the ANNA module has to be configured, the
VDD_MCU net can be connected to enable PC communications by adding a jumper to J7 pins 9 and
10.
Figure 9: Jumper positions for battery powered operation, two jumpers are optional
Connector
annotation
Add jumper
to pins
Description
J7
5, 6
Selects the battery connected to the battery holder as source for the VDD_ANNA net.
9, 10
(Optional) Powers up the Interface MCU, USB hub, and UART to USB converter with 3.3 V.
J22
1, 3
Powers up the ANNA module. The ANNA VCC and VCC_IO pins are connected to the selected
source for the VDD_ANNA net.
2, 4
(Optional) Powers up the peripherals directly connected to ANNA such as LEDs and external
memory with the ANNA supply voltage.
Table 4: Jumper positions for battery powered operation, two jumpers are optional
1.6.4
Battery powered with protection diode, 2.7 V
This use case is meant to protect the battery from current back surges. When using the NFC
interface, there is a risk that the applied electromagnetic field can cause back surges that will
typically damage a non-chargeable battery. To prevent this damage, a schottky diode can be added
in series to the battery, which will block any back current surges. A jumper should then be added to
J7 pins - 3 and 4 instead of 5 and 6.
The diode will lower the voltage level of the battery by about 0.3 V.
Figure 10: Jumper positions for battery powered operation with a protection diode, two jumpers are optional
