Suresh Sahu (VIC9425)

LPC2148 has an inbuilt 10-bit Successive Approximation ADC which is multiplexed among 6/8 input pins of ADC0/ADC1.
The ADC reference voltage is measured across GND to VREF, meaning it can do the conversion within this range. Usually, the VREFPis connected to VDD.
As LPC2148 works on 3.3 volts, this will be the ADC reference voltage.
Now the $$resolution of ADC = 3.3/(2^{10}) = 3.3/1024 =0.003222 = 3.2mV$$
The below block diagram shows the ADC input pins multiplexed with other GPIO pins.
The ADC pin can be enabled by configuring the corresponding PINSEL register to select ADC function.
When the ADC function is selected for that pin in the Pin Select register, other Digital signals are disconnected from the ADC input pins.
Though there are some more registers, we are restricting ourselves to use these registers only as this will be more convenient.
Apart from ADC Global Data register there are more 8 ADC Data registers (one Data register per ADC channel). DONE and OVERRUN bits for each channel can be monitored separately from the bits present in ADC Status register.
One can use the A/D Global Data Register to read all data from the ADC else use the A/D Channel Data Registers. It is important to use one method consistently because the DONE and OVERRUN flags can otherwise get out of synch between the AD0GDR and the A/D Channel Data Registers, potentially causing erroneous interrupts or DMA activity.

About Life Partner Preferences:

What is interrupt ?
An interrupt is an external or internal event that interrupts the microcontroller to inform it that a device needs its service.
Why we need interrupt?
A single microcontroller can serve several devices by two any device needs its service, the device notifies the microcontroller by sending it an interrupt signal. Upon receiving an interrupt signal, the microcontroller interrupts whatever it is doing and serves the device. The program which is associated with the interrupt is called the interrupt service routine (ISR) or interrupt handler
2. Polling- The microcontroller continuously monitors the status of a given device. When the conditions met, it performs the service. After that, it moves on to monitor the next device until every one is serviced
Advantage of interrupt
The polling method is not efficient, since it wastes much of the microcontroller’s time by polling devices that do not need service. The advantage of interrupts is that the microcontroller can serve many devices, Each devices can get the attention of the microcontroller based on the assigned priority . For the polling method, it is not possible to assign priority since it checks all devices in a round-robin fashion.
How does interrupt works?
• Whenever any device needs service of microcontroller, the device notifies the microcontroller by sending it an interrupt signal.
• Upon receiving an interrupt signal, the microcontroller interrupts whatever