MAX1401 Datasheet, PDF (32/36 Pages) Maxim Integrated Products – +3V, 18-Bit, Low-Power, Multichannel, Oversampling Sigma-Delta ADC

+3V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
8051
P3.0
P3.1
V_DD
RESET
MAX1401
DOUT
DIN
SCLK
CS
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.
Figure 13. MAX1401 to 8051 Interface
Listing 2. Bit-Banging SPI Replacement
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