UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 674 o f 792
1. Basic configuration
The DAC is configured using the following registers:
1. Power: The DAC is always on.
2. Clock: In the PCLK_SEL0 register (Table 4–56), select PCLK_DAC.
3. Pins: Select the DAC pin and pin mode in registers PINSEL1 and PINMODE1 (see
Section 9–5).
2. Features
10 bit digital to analog converter
Resistor string architecture
Buffered output
Power down mode
Selectable speed vs. power
3. Pin description
Table29–599 gives a brief summary of each of DAC related pins.
Remark: When the DAC is not used, the VDDA and VREF pins must be connected to the
power supply, and pin VSSA must be grounded. These pins should not be left floating.
4. Register description (DACR - 0xE006 C000)
This read/write register includes the digital value to be converted to analog, and a bit that
trades off performance vs. power. Bits 5:0 are reserved for future, higher-resolution D/A
converters.
UM10237

Chapter 29: LPC24XX Digital-to Analog Converter (DAC)

Rev. 02 — 19 December 2008 User manual
Table 599. D/A Pin Description
Pin Type Description
AOUT Output Analog Output. After the selected settling time after the DACR is
written with a new value, the voltage on this pin (with respect to
VSSA) is VALUE/1024×VREF.
VREF Reference Voltage Reference. This pin provides a voltage reference level for
the D/A converter.
VDDA, VSSA Power Analog Power and Ground. These should be nominally the same
voltages as VDD(3V3) and VSS, but should be isolated to minimize
noise and error.