Analog Devices ADSP-21591, Руководство пользователя

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Figure 3-5:
Example of a Mechanical Switch (Equivalent to Example of Bus Switch)
SoftConfig on the Board
Two Microchip MCP23017 GPIO expanders provide control for individual electronic switches. The TWI2 inter-
face of the processor communicates with the Microchip devices. There are individual switches with default settings
that enable basic board functionality.
The Default Processor Interface Availability table lists the processor and board interfaces that are available by de-
fault. Note that only interfaces affected by software switches are listed in the table.
Table 3-1: Default Processor Interface Availability
Interface Availability by Default
UART0 USB to UART FTDI232RQ
SPI Flash Quad mode enabled
LEDs Enabled
Programming SoftConfig Switches
On the board, two Microchip MCP23017 devices exist. Each of these devices have the following programming
characteristics:
•
Each GPIO register controls eight signals (software switches).
GPIO Register Register Address
GPIOA 0x12
Software-Controlled Switches (SoftConfig)
3–6
EV-21593-SOM
®
Manual