How do you set the clock frequency without exceeding the Baud Rate Error?

In MPLAB® Code Configurator (MCC), the Error for the Baud Rate is calculated based on FCY = FOSC/2. The calculation is made by default with BRGH = 1, so it generates four clocks per bit period. BRGH value can be changed, in order to increase the baud rate, in MCC > UARTx > Registers > Register: UxMODE.

For example PIC24F16KA301, without exceeding the Baud Rate Error value '2', the Baud Rate can be set at a maximum of:

  • 38400 for FRC Oscillator, FRC Postscaler 1:2 resulting in a clock frequency of 4 MHz (the default setting in MCC)
    or
  • 115200 for FRC Oscillator, FRC Postscaler 1:1 and enabling the PLL resulting in a clock frequency of 32 MHz.
© 2018 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.