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BTM41 DATASHEET

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5.6.3

SPI

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

manufacture.

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.

Figure 6