Compute UART Baud Divider

EasyPython

Problem

On an NXP Semiconductors MCU such as the LPC55S69, a UART baud rate is derived from a system clock and an integer divider. Given a system clock, an oversampling factor, and a list of target baud rates, write a function that computes the best divider for each target baud and returns the resulting actual baud rate and percentage error.

Use the formula:

actual_baud = system_clock / (oversample * divider)

For each target baud rate, choose the positive integer divider that minimizes absolute percentage error. If two dividers produce the same error, return the smaller divider.

Formal Specification

Input:
- system_clock: integer clock frequency in Hz
- oversample: integer oversampling factor
- targets: list of integer target baud rates
Output:
- A list of lists, where each result is: [target_baud, divider, actual_baud, error_percent]
- actual_baud and error_percent should be rounded to 2 decimal places.

Constraints

1 <= len(targets) <= 10^4
1 <= system_clock <= 10^9
1 <= oversample <= 256
1 <= targets[i] <= 10^7
Divider must be a positive integer

Function Signature

def compute_uart_baud_settings(system_clock, oversample, targets):

Use the formula:

actual_baud = system_clock / (oversample * divider)

For each target baud rate, choose the positive integer divider that minimizes absolute percentage error. If two dividers produce the same error, return the smaller divider.

Formal Specification

Input:
- system_clock: integer clock frequency in Hz
- oversample: integer oversampling factor
- targets: list of integer target baud rates
Output:
- A list of lists, where each result is: [target_baud, divider, actual_baud, error_percent]
- actual_baud and error_percent should be rounded to 2 decimal places.