Rainbow-electronics MAX1401 Manual de usuario descargar pdf (Pagina 32)

Bit-Banging Interface (80C51, PIC16C54)

Any microcontroller can use general-purpose I/O pins

to interface to the MAX1401. If a bidirectional or open-

drain I/O pin is available, reduce the interface pin count

by connecting DIN to DOUT (Figure 13). Listing 2

shows how to emulate the SPI in software. Use the

same initialization routine shown in Listing 1.

For best results, use a hardware interrupt to monitor the

INT pin and acquire new data as soon as it is available.

If hardware interrupts are not available, or if interrupt

latency is longer than the selected conversion rate, use

the FSYNC bit to prevent automatic measurement while

reading the data output register.

MAX1401

+3V, 18-Bit, Low-Power, Multichannel,

Oversampling (Sigma-Delta) ADC

32 ______________________________________________________________________________________

P3.0

P3.1

RESET

DOUT

DIN

SCLK

8051

MAX1401

Figure 13. MAX1401 to 8051 Interface

Listing 2. Bit-Banging SPI Replacement

1 2 ... 27 28 29 30 31 32 33 34 35 36

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Rainbow-electronics MAX1401 Manual de usuario Pagina 32