MAX1403 Maxim, MAX1403 Datasheet - Page 32

• Manufacturer Part Number: MAX1403
• Description: +3V / 18-Bit / Low-Power / Multichannel / Oversampling Sigma-Delta ADC
• Manufacturer: Maxim

Figure 13. MAX1403 to 8051 Interface
+3V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
32
Listing 2. Bit-Banging SPI Replacement
______________________________________________________________________________________
/* Low-level function to write 8 bits
** The example shown here is for a bit-banging system with (CPOL=1, CPHA=1)
*/
void WriteByte (BYTE x)
{
}
/* Low-level function to read 8 bits
** The example shown here is for a bit-banging system with (CPOL=1, CPHA=1)
*/
BYTE ReadByte (void)
{
}
return x;
drive SCK pin high
count = 0;
while (cout <= 7)
{
}
x = 0;
drive SCK pin high
count = 0;
while (cout <= 7)
{
}
8051
if (bit 7 of x is 1)
else
drive SCK pin low
x = x * 2;
drive SCK pin high
count = count + 1;
x = x * 2;
drive SCK pin low
if (DOUT pin is high)
drive SCK pin high
count = count + 1;
drive DIN pin high
drive DIN pin low
x = x + 1;
P3.0
P3.1
V
DD
SCLK
CS
RESET
DOUT
DIN
MAX1403
Any microcontroller can use general-purpose I/O pins
to interface to the MAX1403. 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.
Bit-Banging Interface (80C51, PIC16C54)