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4.8.2

I2C Interface

As this I2C interface is software-driven it is suited to relatively slow functions such as

driving a dot matrix LCD, keyboard scanner or EEPROM. If it is not used, then PIO[7:6]

are available to form a software-driven master I2C interface.

4.8.3

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