Rainbow-electronics MAX781 Bedienungsanleitung PDF herunterladen (Seite 21)

Interfacing the MAX781 to an

IBM Compatible PC

Figure 1 shows the MAX781 typical operating circuit.

On power-up, with 4.8V < BATT < 18V and CE = SCLK

= DIN = 0V, the MAX781 is in low-power mode. 3OUT

outputs +3.3V linear regulated from BATT, and REF

outputs +2.5V. INT should output a 3.3V logic high.

Neither DHI nor DLO should be switching. Serial data

must be sent to the MAX781 in order to change modes.

The parallel printer interface on a personal computer

can be used to send serial control data to the MAX781.

Listing 3 shows a simple Microsoft Quick Basic pro-

gram for communicating with the MAX781 over the

LPT1 parallel interface port.

MAX781

PDA/Hand-Held Computer Power Controller

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Rainbow-electronics MAX781 Bedienungsanleitung Seite 21