Texas Instruments SLAU081 manual Switches, Clock/Timer Routing, Stand-Alone-Mode, SW1-1

Switches

2.2.7Clock/Timer Routing

	A variety of options are available to the user. Be careful about altering these.
	Clock/Timer Routing
Reference	Functional Description
Designator
W21	This jumper defines the clock that the ADC and DAC use for all their timing. The user can select
	either the output from W23 or the output from W22 to be the base clock for the system.
W23	This jumper allows the user to select either an external clock, or the onboard 20-MHz oscillator for
	conversion. In addition, this signal is fed to W20.
W20	W20 provides a route for the EVM to generate CLKS for a DSP if so desired.
W22	This jumper enables the user to select either the transmit clock from a DSP, or the output
	from W24.
W24	W24 connects or isolates the timer output from a DSP.

2.3 Switches

There are three switches present on the EVM:

-One 8-pin DIL switch which houses four individual switches; these are denoted SW1-1, SW1-2, SW1-3, and SW1-4.

-Two momentary push-button switches

Features and functions of each switch:

Reference	Function	Default
Designator		Condition
SW1-1	Selects either stand-alone mode (SAM) or user mode	SAM
SW1-2	Reserved
SW1-3	Reserved
SW1-4	Reserved

2.3.1Stand-Alone-Mode, SW1-1

SW1-1 chooses either stand-alone mode or user mode. If the switch is set to the off position, SAM is selected and the EVM ignores all signals generated by a DSP. In addition, the EVM will not output any signals to a DSP or microprocessor.

In this mode, SW2 and SW3 are used to reset the EVM’s logic and initiate automatic conversions from the ADC, in addition to automatically routing the serial bit stream from the ADC to the DAC for reconstruction.

Reference	Function
Designator
SW2	Initiates ADC and DAC conversions in SAM
SW3	Forces the EVM’s control logic into a known state

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