ANNA-B4 series - System integration manual
UBX-21000517 - R03
Contents
Page 21 of 74
C1-Public
Consider the following when migrating from ANNA-B1 to ANNA-B4; that is, mounting an ANNA-B4
module onto a PCB originally designed for ANNA-B1:
•
The USB interface on open CPU, ANNA-B40 modules is not accessible as
USBDP
and
USBDM
signals on pins 34 and 35 are both connected to GND.
•
ANNA-B4 pins
GPIO_10
,
GPIO_11
,
GPIO_49
,
GPIO_50
, and
GPIO_51
cannot be used. These
signals are connected to GND and must be configured as inputs.
•
VBUS
on pin 21 is an additional pad. It is unconnected.
•
The Serial Wire Debug (SWD) signals
SWDIO
and
SWDCLK
available on the open CPU modules
have the same physical location on ANNA-B4 as they do on ANNA-B1. However, the pin
numbering of the two differs: On ANNA-B4 these signals are on pins 41 and 42. On ANNA-B1
they are on pins 39 and 40.
•
Check that the power supply can meet the higher current requirements for ANNA-B4.
•
Check the PCB to make sure that there is no risk for short circuits under the additional pins
(21, 26, 47, and 52) on ANNA-B4. Remember that the solder mask is not a true insulator.
Consider the following when designing a PCB preprepared for the interchangeable placement of
ANNA-B1 and ANNA-B4:
•
All GND pins on ANNA-B1 and ANNA-B4 modules must be grounded regardless of whether
these have another function on the other module (ANNA-B4). These pins must then be
configured as inputs.
•
The USB interface supported in ANNA-B402 open-CPU modules is not accessible since
USBDP
(D+) and
USBDM
(D-) are connected to GND.
•
The SWD interface supported on ANNA-B102 and ANNA-B402 open CPU modules is
connected to the same physical pins on both variants. Route this to a connector or test point
(TP).
•
Implement a power supply capable of sourcing the higher current requirements of ANNA-B4
modules.
☞
The u-connectXpress software supported on ANNA-B412 modules includes secure-boot
functionality. The SWD interface is not available.
☞
When migrating open CPU software to ANNA-B402 it is necessary to recompile the software with
the correct pin definition, base port and SoftDevice.
☞
Although the pin numbering for ANNA-B1 is different than that on ANNA-B4, the physical
placement of all common pins is the same.
☞
Although ANNA-B1 and ANNA-B4 are pin compatible, it is advisable to revise the layout of the
application PCB to match ANNA-B4 footprint. This ensures that all required pads for the migration
upgrade to ANNA-B4 are available. If this for any reason is not viable, review the PCB layout to
ensure that no top layer traces interfere with the additional pads included on ANNA-B4.