Microchip Embedded Calculator

Calculate timer values, baud rates, memory usage, and other essential embedded development parameters.

Timer Calculator
Baud Rate Calculator
Memory Calculator
PWM Calculator

Timer Period Formula: T = (PR + 1) × (Prescaler / Fosc)

Where: T = Timer Period (seconds), PR = Period Register Value, Prescaler = Timer Prescaler, Fosc = Oscillator Frequency (Hz)

Hz
Microcontroller oscillator frequency (e.g., 16MHz)
Desired timer period (e.g., 1ms = 0.001s)
1:1
1:2
1:4
1:8
1:16
1:32
1:64
1:256
Select a timer prescaler value
Timer bit resolution (maximum period register value)

Baud Rate Formula: Baud Rate = Fosc / [4 × (SPBRG + 1)] (Low Speed) or Fosc / [16 × (SPBRG + 1)] (High Speed)

Where: SPBRG = Baud Rate Generator Register Value

Hz
Microcontroller oscillator frequency (e.g., 16MHz)
bps
Desired serial communication baud rate
1200
2400
4800
9600
19200
38400
57600
115200
UART mode (most common: Asynchronous 8-bit)
Baud rate generator register size
Automatically select High Baud Rate bit for best accuracy

Memory Calculations: Calculate memory requirements for code, data, and stack usage in embedded applications.

bytes
Size of compiled program code
bytes
Static and global variable memory usage
bytes
Maximum stack memory requirement
bytes
Microcontroller total flash memory size
bytes
Microcontroller total RAM size
bytes
Non-volatile data storage usage

PWM Formulas: PWM Period = (PRx + 1) × Tcy × (TMRx Prescale Value), Duty Cycle = (OCxRS / (PRx + 1)) × 100%

Where: PRx = Period Register, Tcy = Instruction Cycle Time, OCxRS = Duty Cycle Register

Hz
Desired PWM output frequency
%
Desired PWM duty cycle (0-100%)
Hz
Microcontroller oscillator frequency
PWM timer prescaler value
PWM resolution in bits
Automatically select best prescaler for required frequency
Calculating...

Microchip Embedded Development

Microchip Technology (formerly Atmel) produces a wide range of microcontrollers including the popular AVR (ATmega, ATtiny) and PIC families. These microcontrollers are used in embedded systems for applications ranging from simple control systems to complex IoT devices.

Common Microchip Microcontrollers:

  • PIC16F/18F: 8-bit microcontrollers with various memory sizes and peripherals
  • PIC24/dsPIC: 16-bit microcontrollers with DSP capabilities
  • PIC32: 32-bit MIPS-based microcontrollers
  • ATmega: 8-bit AVR microcontrollers (Arduino compatible)
  • ATtiny: Small 8-bit AVR microcontrollers for simple applications
  • SAM (ARM Cortex): 32-bit ARM-based microcontrollers

Timer Calculations

Timers are essential peripherals in microcontrollers used for timing events, generating precise delays, measuring time intervals, and creating PWM signals.

Timer Period Calculation Formula:

T = (PR + 1) × (Prescaler / Fosc)

Where:

  • T: Timer period in seconds
  • PR: Period register value (0 to 2^n - 1, where n is timer resolution)
  • Prescaler: Timer prescaler value (1, 2, 4, 8, 16, 32, 64, 128, 256, etc.)
  • Fosc: Oscillator frequency in Hz

Baud Rate Calculations

Baud rate determines the speed of serial communication. Accurate baud rate calculation is essential for error-free UART communication.

Baud Rate Calculation Formulas:

Asynchronous 8-bit (Low Speed): Baud Rate = Fosc / [64 × (SPBRG + 1)]

Asynchronous 16-bit (High Speed): Baud Rate = Fosc / [16 × (SPBRG + 1)]

Synchronous Master: Baud Rate = Fosc / [4 × (SPBRG + 1)]

Where SPBRG is the baud rate generator register value.

Memory Considerations

1

Flash Memory: Stores program code and constant data. Must be large enough for your compiled application.

2

RAM: Stores variables, heap, and stack during program execution. Insufficient RAM causes crashes.

3

EEPROM: Non-volatile memory for storing configuration data that must persist after power loss.

4

Stack: Memory area for function calls, local variables, and interrupt context. Must be sized appropriately.

5

Heap: Dynamic memory allocation area. Often avoided in embedded systems due to fragmentation risks.

PWM Calculations

Pulse Width Modulation (PWM) is used for controlling power to inertial electrical devices, creating analog-like outputs, and controlling servo motors.

PWM Formulas:

PWM Period = (PRx + 1) × Tcy × (TMRx Prescale Value)

PWM Frequency = 1 / PWM Period

Duty Cycle = (OCxRS / (PRx + 1)) × 100%

Where:

  • PRx: Period register value
  • Tcy: Instruction cycle time = 4 / Fosc (for most PIC MCUs)
  • OCxRS: Duty cycle register value

Frequently Asked Questions

Choose the largest prescaler that gives you a period register value within your timer's range. This maximizes timer resolution. If the calculated period register value is too large for your timer (greater than 2^n-1), increase the prescaler. If it's too small (less than 1), decrease the prescaler.

Baud rate errors occur when the calculated baud rate generator value doesn't produce an exact baud rate. Errors under 2% are usually acceptable for asynchronous communication. Higher errors can cause framing errors. Use the calculator to find the closest achievable baud rate with minimal error for your oscillator frequency.

Stack requirements depend on: 1) Maximum depth of nested function calls, 2) Size of local variables in each function, 3) Interrupt service routine requirements. A good starting point is 256-512 bytes for simple applications, 1-2KB for medium complexity, and more for complex applications or those using RTOS. Always include a safety margin.

8-bit timers count from 0-255, suitable for short time intervals. 16-bit timers (0-65535) are common for medium timing requirements. 32-bit timers (0-4,294,967,295) are used for very long intervals or high-resolution timing. Higher bit count provides longer maximum intervals but may use more CPU resources.

PWM resolution in bits = log₂(PRx + 1). For example, a 10-bit resolution means you have 1024 discrete duty cycle steps (0-1023). Higher resolution provides smoother control but may require lower PWM frequencies. The calculator helps you find the optimal balance between frequency and resolution for your application.