Integration Manual

ANNA-B4 series - System integration manual
UBX-21000517 - R03 Contents Page 37 of 76
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4.5.2.2 Preparing the Device Firmware Update (DFU) package
The package has a special DFU package format. You use nrfutil to generate the DFU package.
Use the following command options for an application that does not use SoftDevice:
nrfutil pkg generate --hw-version 52 --sd-req 0x00 --application-version 0 --application
app.hex app.zip
Use the following command options for an application with SoftDevice:
nrfutil pkg generate --hw-version 52 --sd-req 0xCA --sd-id 0xCA --softdevice
s140_nrf52_7.0.1_softdevice.hex --application-version 0 --application app.hex sd_app.zip
4.5.2.3 Flashing the DFU package
The generated DFU package is flashed to the module using the following nrfutil command options:
nrfutil dfu serial -pkg app.zip -p COM95 -b 115200 -fc 1
☞ When the DFU package is flashed for the first time there is no application to boot, which causes
the bootloader to automatically stop in DFU mode. On subsequent reboots, you need to stop the
bootloader in DFU mode by driving SWITCH_2 low during startup.
4.5.2.4 Hardware prerequisites for using the bootloader
To use the pre-flashed bootloader the hardware pins for UART and SWITCH_2 must be mapped
according to Table 16. This is the same pin mapping that is used on the EVK-ANNA-B4 and used in the
u-connectXpress software.
Signal
Pin mapping (nRF pin number)
UART_RX
IO_20 (P0.02)
UART_TX
IO_19 (P0.03)
UART_CTS (optional)
IO_37 (P0.22)
UART_RTS (optional)
IO_36 (P0.16)
SWITCH_2
IO_40 (P0.15)
Table 16: Pin mapping used by bootloader
The UART_CTS and UART_RTS (flow control signals) are optional but u-blox recommends using flow
control over the UART.