Rainbow Electronics MAX1400 - Manual (Page 30)

Bit Banging Interface (80C51, PIC16C54)
Any microcontroller can use general-purpose I/O pins
to interface to the MAX1400. If a bidirectional or open-
drain I/O pin is available, reduce the interface pin count
by connecting DIN to DOUT (Figure 14). Figure 15
shows how to emulate the SPI in software. Use the
same initialization routine shown in Figure 13.
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.
MAX1400
+5V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
30 ______________________________________________________________________________________
V
DD
P3.0
P3.1
RESET
DOUT
DIN
SCLK
CS
8051
MAX1400
Figure 14. MAX1400 to 8051 Interface
Figure 15. Bit Banging SPI Replacement