5.6 Serial Interfaces
This is a standard UART interface for communicating with other serial devices. The UART
interface provides a simple mechanism for communicating with other serial devices using
the RS232 protocol.
When the module is connected to another digital device, UART_RX and UART_TX
transfer data between the two devices. The remaining two signals, UART_CTS and
UART_RTS, can be used to implement RS232 hardware flow control where both are
active low indicators.
Note: The serial port interface(UART)can be used for system debugging. Don’t
support to use command set for profile function application by UART, such as
HFP/A2DP/AVRCP and so on. These profiles function application can be controlled
only by PIO, such as pairing/connect/answer/play/pause/next/previous function
application and so on.
The synchronous serial port interface (SPI) can be used for system debugging. It can also be
used for in-system programming for the flash memory within the module. SPI interface
uses the SPI_MOSI, SPI_MISO, SPI_CSB and SPI_CLK pins. Testing points for the SPI
interface are reserved on board in case that the firmware shall be updated during
The module operates as a slave and thus SPI_MISO is an output of the module.
SPI_MISO is not in high-impedance state when SPI_CSB is pulled high. Instead, the
module outputs 0 if the processor is running and 1 if it is stopped. Thus the module
should NOT be connected in a multi-slave arrangement by simple parallel connection
of slave SPI_MISO lines.