What is PWM in LPC2148?
PWM or Pulse Width Modulation is a technique that modulates the width of a rectangular pulse wave in order to get a variation in the average value of the resulting wave. PWM in LPC2148 are classified in to 2 types: Single Edged PWM signal and Double Edged PWM signal.
How many match registers are there in PWM of LPC2148?
seven-match registers
LPC2148 PWM Module LPC2148 has 6 PWM output pins which can be used as 6-Single edged or 3-Double edged. There as seven-match registers to support these 6-PWM output signals.
What is double edged PWM?
In Double Edge PWM the Pulse can be Positioned anywhere within the Period. Its called “Double Edge” because both the Edges are Modulated or Varied. In applications like Multi-Phase Motor control Double Edge PWM is used where the Pulse is Center Aligned to reduce Harmonics.
Which timer is used for PWM as clock source?
We will use the simplest timer, TIMER0 for PWM generation. So we have an 8 bit counter counting from 0 to 255 and then resetting to 0 and so on.
Which register is responsible for controlling internal DAC of LPC2148?
Digital to Analog Control Register (DACR)
| DAC Register (DACR – address OxE006 C000) Bit Description | ||
|---|---|---|
| 16 | BIAS | The settling time of the DAC is 2.5 µs and the maximum current is 350 µA. |
| 31:17 | – | Reserved, user software should not write ones to reserved NA bits. The value read from a reserved bit is not defined. |
Which register in LPC2148 contains PLL multiplier and divider values?
PLLCON (PLL Control Register) The PLLCON register contains the bits that enable and connect the PLL. Enabling the PLL allows it to attempt to lock to the current settings of the multiplier and divider values. Connecting the PLL causes the processor and all chip functions to run from the PLL output clock.
What are features of LPC2148?
LPC2148 Key Features: 16/32-bit ARM7TDMI Microcontroller in a tiny LQFP64 package. 40 kB of on-chip static RAM and 512 kB of on-chip flash memory. 128-bit wide interface/accelerator enables high-speed 60 MHz operation. In-System Programming/In-Application Programming (ISP/IAP) via on-chip boot loader software.
What is the use of pulse width modulation?
Pulse-width modulation (PWM) is used for controlling the amplitude of digital signals in order to control devices and applications requiring power or electricity.
How trailing edge of PWM signal are considered position modulated?
It is negative edge triggered. Hence, with the trailing edge of the PWM signal, the output of the monostable goes high. With the modulating signal, the trailing edge of PWM signal shifts, thus with that shift, the PPM pulses shows shifts in its position.
How many PWM pins does the LPC2148 have?
LPC2148 has 6 PWM output pins which can be used as 6-Single edged or 3-Double edged. There as seven-match registers to support these 6-PWM output signals. Below block diagram shows the PWM pins and the associated Match (Duty Cycle) registers. The below table shows the registers associated with LPC2148 PWM.
How is pulse width modulation used in microcontroller?
In this tutorial we will explore the use of PWM in LPC2148 ARM7 Microcontroller. Pulse Width Modulation (PWM) is very useful technique for controlling analog circuits with processors digital outputs. PWM used in a wide variety of applications ranging from measurement and communications to power control.
What happens when you write 0 to LPC2148 GPIO?
Writing 1 produces a LOW level at the corresponding port pin and clears the corresponding bit in the IOSET register. Writing 0 has no effect. If any pin is configured as an input or a secondary function, writing to IOCLR has no effect. So this is the theory of LPC2148 GPIO.
What are the rules for single edged PWM?
The Rules for Single Edged PWM are as : 1) All single edged PWM outputs will go high at the beginning of a PWM cycle unless their match value is 0. 2) Each PWM output will go low when its match value is reached. Note : If no match occurs i.e Match value is greater than Period then the output will remain high!