Motorola USB08 Betriebsanleitung PDF herunterladen (Seite 34)

PC controls reset

Tick this box if the host PC is able to control the reset cycle on the target board.

Using DTR/RTS

Select whichever signal is used for the remote re-setting.

With +ve/-ve going pulse

Select the pulse polarity. For the avoidance of doubt about the meaning of RS232 'asserted', etc. the

descriptions +ve/-ve refer to the actual polarity of the pulse with respect to the common ground pin

(pin 5 on the DB9 connector). Note that most RS232 level shifter chips on target boards invert this

polarity, and also that RS232 line receivers usually bias their inputs so that a disconnected input

appears to be at a negative voltage.

Reset downtime

Time, in seconds, for the reset pulse to remain in the 'low' state. The minimum value is 0.1 s (100 ms),

and the maximum 999 s (16 min 39 sec - a long wait!). The important thing is that Vdd falls to within

100 mV of Vss to achieve a reliable reset. The default value is 0.1 seconds, but this may well be too

short - it all depends on the target board circuitry.

Remote Monitor/User Mode Switch

With the necessary logic hardware on the target board, the PC can be used to control whether the

MCU runs in Monitor mode, or executes its own user-written program; using whichever RS232 output

signal is not already being used by the remote reset function. See Monitor/User Mode Switching on

page 11 and Appendix B - Hardware for more details.

PC controls switching

Tick this box if the host PC is able to toggle the output.

Using:

Select whichever RS232 output pin is to control the switching. If DTR is selected then the labels in

this box will change to DTR rather than RTS.

General-purpose switch is 'ON' when RTS is positive/RTS is negative

Choose the pin voltage level which corresponds to the 'ON' state.

General

Note that changes made on this tab will cause the COM port to close (disconnect) if the Settings

dialog is closed by clicking the 'OK' button.

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Motorola USB08 Betriebsanleitung Seite 34