13
Cortex Debug
Connector
IO
Using Single Wire Debug to burn bootloader and debug the
board
ADC0
I
Connected to BG77. General purpose analogue to digital converter
ADC1
I
Connected to BG77. General purpose analogue to digital converter
GPIO26
IO
Connected to BG77. General purpose IO
GPIO64
IO
Connected to BG77. General purpose IO
SPI
IO
Connected to BG77.
USIM
I
Used to insert a Nano USIM. Connected to BG77
USB Boot
I
Connected to BG77. Force the BG77 to enter emergency download
mode
Precaution
The USB dongle runs at 3.3V. The maximum voltage that the I/O pins can tolerate is 3.3V.
Applying voltages higher than 3.3V to any I/O pin could damage the board
2.9
BG77 chipset
All functionality of the BG77 shipset shall be implemented excluding the following features. That is, the
following features are not supported [1][2].
-
Audio, Earphone, and Codes are not supported.
-
PCM and I
2
C are not supported
-
PSM_IND and AP_READY are not supported
2.10
Interface between SAM21D and BG77
The Microcontroller communicates with the BG77 through UART interfaces:
-
UART1:
(PA12/PA13/PA14/PA15).
Used for data transmission and AT command communication
115200bps by default. The default frame format is 8N1 (8 data bits, no parity, 1 stop bit) Support
RTS and CTS hardware flow control.
-
UART3:
(PB23/PB22). Used for outputting GNSS data or NEMA sentences 115200bps baud rate.
