Rainbow Electronics MAX1329 - Manual (Page 64)

MAX1329/MAX1330
12-/16-Bit DASs with ADC, DACs, DPIOs, APIOs,
Reference, Voltage Monitors, and Temp Sensor
64 ______________________________________________________________________________________
Communication with a Peripheral Device
Powered by the MAX1329/MAX1330
The circuit in Figure 27 shows the MAX1329/MAX1330
providing an interface between a µC and a peripheral
device powered by different supply voltages. This elimi-
nates the need for external level-translation circuitry due
to the different supply voltages. The internal charge
pump boosts the µC supply voltage (DV
DD
) to the periph-
eral device supply voltage (AV
DD
). See the APIO Control
and APIO Setup registers to program APIO2–APIO4 as
DIN, SCLK, and
CS outputs to the peripheral device,
respectively, and APIO1 as the DOUT input from the
peripheral device. The digital inputs at DIN, SCLK, and
CS are level-translated from DV
DD
to AV
DD
and output at
the configured APIO2, APIO3, and APIO4 outputs. The
digital output at DOUT is level-translated from AV
DD to
DV DD from the configured APIO1 input.
µC
DPIO2
OUTPUT
SCK SCLK
MOSI DIN
MISO DOUT
INTERRUPT
DPIO1
HCLKIN CLKIO
32.768kHz
XOUT
XIN
INTERRUPT
INTERRUPT
MAX1329
MAX1330
RST1
CS
RST2
RESET
Figure 26. Digital-Interface Connections
µC
APIO4 OUTPUT
SCK SCLK
MOSI DIN
MISO DOUT
APIO3
APIO2
APIO1
PERIPHERAL
DEVICE
DIN
DOUT
SCLK
AGND
DGND
AV DD
DV DD
AGND DGND
DV DD
AV DD
C1A C1B
C FLY
EXTERNAL 1.8V TO 3.6V
3.0V/4.0V/5.0V
POWER
SUPPLY
C AVDD
C DVDD
MAX1329
MAX1330
CS CS
Figure 27. Communication with a Peripheral Device Powered by the MAX1329/MAX1330