(editor’s note: Intrigued by the problem? Have a question or optional solution? Then click the “Read more” link and follow the conversation on EDAboard.com or log in to EDAboard and participate in the microcontroller forum thread.)

16 X 1024 LED matrix scanning – I have a P10 module arranged in a 16 row X 1024 column matrix. To control, I have to use an ARM NXP LPC1768 microcontroller with a maximum frequency up to 100 MHz for scrolling text display. I am trying to understand the scan rate for each column in order to update the display properly. Can anyone recommend how to calculate frequency based on the number of columns and rows? Read more

How to detect dry run and overload using PIC – I need to use a PIC microcontroller to detect dry run and overload for a 220V AC 50 Hz rated pump. Read more

AC voltage measurement issue – I am planning to measure AC RMS using a microcontroller. Because of size constraints, I don’t want to use step-down transformer. By using a bridge rectifier, the input AC voltage is converted into DC. Using a voltage divider network, the rectifier volt is reduced and the output of the voltage divider is filtered and given to microcontroller ADC. My issue is that after using the bridge rectifier, I am not getting the proper rectified output. The actual output is below. Read more

Save button state for elevator – How do you use the shift register to store the multiple push buttons status until needed for elevator requests? Read more

PIC16F628A and a simple timer digit error – I am new at programming PIC microcontrollers. When multiplexing a theoretically simple 4 digits 7seg display (common anode) simulated in ISIS PROTEUS, it runs perfectly. But when I put it in breadboard testing, the digits are all messed up like the photo demonstrates. Anyone knows wich are the common causes for this type of error? Read more

LCD 1 displays garbled values after long usage – I am using a 16″, 2-LCD display for my design. It works fine initially but during long runs, it displays wrong characters. The controller works fine for the other operations. I am using the PIC16f876 controller and LCD Lampex 16200. Read more

RF communication through microcontroller – I want to send data from one microcontroller to another microcontroller using RF technology. I am using 433 Mhz TX and 433 Mhz RX modules. I have connected data pins to respective TX and Rx pins of modules. But no data is being received at the receiver end. Read more

How to stabilize ADC using PIC – I am writing a C code using mikroC and PIC16F676. When I test it on board, the Dl_Relay pin transit between ON and OFF multiple times for particular ADC value, it shows glitches on an oscilloscope – the D_relay pin switches ON and OFF for different ADC values. When I test it on hardware, the same thing happens. Why? Read more

PID control using PIC16f877A – I have to develop a PID control setup for temperature using the PIC16f877A controller. Kindly provide me with the mikroC code for PID controller using PIC16f877a. I also need help determining the PID gains of a system. Read more

Arduino mega + SSD1963 problem – I have designed a custom PCB with the ATmega2560 for my project. Have a 4.3-inch TFT on it with an SSD1963 controller (16-bit data bus). All the data and control lines are translated to 3.3 logic with 74AHC541 buffers. The connection from my PCB to display module is via a 40- pin flat ribbon cable. I have tested the display using the ATmega2560 board and all the codes are working fine. But whenever I have assembled on this board, the TFT gives only a white screen. I have a pullup in the reset line. I am really fed up with this issue. Below are my schematics. Read more