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Questions tagged [lpc1768]

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1answer
46 views

Does Interrupt interrupt a blocked read call

If you were to read() incoming socket data in an infinite while loop, would an interrupt with top priority still run its ISR if the read() call is blocked (i.e. no data in the buffer)?
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0answers
21 views

LPC1768 Clock Out pin

In the LPC1768 User manual, it is written P1.27 2nd function is CLKOUT. But in the keil debugger it is written reserved. When I checked clock out pin after enabling, I only get 0 V.
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53 views

LPC1768 internal RTC time register is not incrementing

Value is read right,but time is not incrementing. ...
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4answers
41 views

LPC1768 vs Timer0, etc

I realise that the LPC1768's Systick is a standard accross ARM boards, while Timer0 and co, are NXP additions. Is there any particular reason to use one over the other? Say you want to generate a ...
3
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4answers
1k views

What are these exposed copper rectangles for on the mbed NXP LPC1768?

Today I noticed some exposed copper rectangles on the bottom of an mbed NXP LPC1768 dev board. They don't look like they're meant for components. I think they may just be test points, but I'm curious ...
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2answers
91 views

Inverting REFCLOCK of Ethernet PHY

A few years ago I had to design a board that uses the NXP LPC1769 MCU and had Ethernet connectivity. I was in need of a PHY chip and the LAN8720 was choosen. During design however, I noticed that NXP ...
1
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1answer
117 views

UART pins interfacing with Barcode without handshaking signals

I am concerned about bar code interface with LPC1768/LPC1769 controller.. If I use only UART-TX, UART-RX, GND pin of controller only to interface with barcode scanner module which has UART or RS232 ...
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0answers
97 views

Flashing LPC1768 with OpenOCD

I'm venturing into JTAG flashing, and thought OpenOCD would be a good place to start. I had a quick look through the documentation and found it hideously complicated. Likewise, the very few "tutorials"...
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0answers
69 views

Loading program on LPC1768 dev board

I recently purchased a rather inexpensive LPC1768 development board from dx.com. The board can supposedly be programmed via USB (in a similar fashion to the mbed). To open the device as a disk, you ...
0
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1answer
91 views

TLV5606 interfacing

Has anyone had any experience interfacing the TLV5606 DAC with a microcontroller (via SPI)? I'm having trouble getting any output from the DAC, which I suspect is down to my code. Does anyone have ...
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0answers
67 views

Varying performance of mbed, depending on Power Supply

I've written a very basic program (without the mbed library) to turn on all LEDs on an mbed board (https://os.mbed.com/platforms/mbed-LPC1768/): ...
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2answers
206 views

How fast is mbed Digital Out

I need to output 8-bit integers via parallel (i.e. using 8 pins on the same port) at 1024hz. From what I can see, I have two options: 1) Write to each pin individually using DigitalOut. 2) Avoid the ...
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0answers
48 views

Accessing encoder buffer from a task

The LPC1768 has a quadrature encoder interface (QEI), which stores the encoder count in a fixed memory location. Can this be accessed in the typical way, through a FreeRTOS task (I think header files ...
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2answers
172 views

LPC1768 Baud rate

I've been trying to configure UART module of LPC1768. Board comes with a crystal oscillator of 12Mhz. It does nothing more than receiving a character and transmitting it at the same time. I am using ...
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0answers
103 views

synchronised tasks and interrupts conflicts with filesystem

my program include timers (timer0 to call an ISR periodically, timer3 to measure execution time), spi to read (without DMA) and fatfs. I call a function each 250 µs periodically using timer0, this ...
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2answers
141 views

Configuring Registers in ARM Cortex M3

I've been learning to program LPC2148(ARM7) microcontroller, and today I got hold of an LPC1768(Cortex M3) board. By referring it's manual, I tried to make a LED blink program and did it as follows, ...
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2answers
223 views

LPC1769 and ATMega88 UART interface

I am referring below schematics for implementation. LPC1769 -- > 3.3V Powered AtMega88 -- > 5V Powered LPC1769 UART pins are 5V tolerant. And due to some reason, can't operate AtMega88 on 3.3V ...
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1answer
64 views

What is the relation between DAC peripheral bus and conversion/settling time

Going through the datasheet and the LPC17xx user manual, what is quite evident is how to select the various clocking options for the peripheral clock divider, i.e: ...
1
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1answer
176 views

Data corruption while using RTOS queue services

I am trying to create a gatekeeper task to display the sensor data over the screen via UART. The attributes are defined in the structure as follows, ...
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0answers
101 views

Defining a variable in the bit-banded area

I wonder to know is there anyone who define a variable in bit-banded region in c programming language for cortex-M3 particularly LPC17XX. I have followed the compiler attribute for Keil (...
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2answers
181 views

LPC1768 doesn't generate RTC clock while other LPC1768 does

I have this board with LPC1768 and 32.768KHz crystal but the RTC does not work. By directing RTC clock to the CLKOUT pin I realized that there is no RTC clock so it makes sense that it's not working. ...
1
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1answer
228 views

mbed LPC1768 with optocoupler for 5 V output

I am generating a PWM at 20kHz to drive a motor. The signal goes into a motor controller which range is from 0 to 5 volts. Since the PWM output is 3.2 volts I need to amplify it. For that I am using ...
4
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5answers
414 views

Is it possible to identify what magnet has crossed over a hall effect sensor?

We are currently doing a project with DCC locomotives, involving a micro controller LPC1768. Now the scenario is that we have a railway and under the railway we have hall effect sensors which the ...
0
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1answer
178 views

LPC17xx internal pull-ups on JTAG etc

The the NXP LPC17xx Cortex-M3 family has internal pull-up resistors on some important pins such as the JTAG, NMI, Bootloader-select pin etc. While reading the data-sheet I learned that the pull-up is ...
1
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1answer
741 views

PIR sensor not working

I am new to electronics and microcontrollers. I am using an LPC1768 and a hc sr501 PIR sensor to create a simple motion detector. I have connected the pins of the PIR sensor to the breadboard and the ...
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1answer
94 views

How i can store 64 byte data into flash faster as 1 ms?

I have one problem with store data into flash on my uC LPC1759. I need to save 64 byte data into flash, but when i use IAP-Interface, it takes more than 1 second. Is there a way to make it faster than ...
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2answers
330 views

calculate uptime of LPC1768

i want to calculate the uptime of LPC 1768 from when it begins running. for example a function like millis(); in arduino.
1
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1answer
196 views

Cortex M3 debugging: Intermittent partial load of binary with pyOCD, then timeout

I'm debugging an embedded system and get intermittent binary loading errors when flashing the binary through gdb (well, arm-none-eabi-gdb, the toolchain gdb client). Here are the details of my setup: ...
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2answers
1k views

Output clock of the LPC1768?

I am using NXP's LPC1768 development board and I came across the User Manual for this part and page 67/849 section 4.10 descusses the External Clock Output. I couldn't figure out which pin out of the ...