The factory calibrates the internal oscillator block output (INTOSC). However, the INTOSC frequency may drift as VDD or temperature changes from Copy PIC12F1822 Flash Memory Data, and this directly affects the asynchronous baud rate even after MCU cracking has been completed. The baud rate clock can be adjusted, but requires a reference clock source of some kind.
The method to adjust the value in the Baud Rate Generator can be done automatically with the Auto-Baud Detect feature. There may not be fine enough resolution when adjusting the Baud Rate Generator to compensate for a gradual change in the peripheral clock frequency after Read Chip ATTINY25V Software.
The Baud Rate Generator (BRG) is an 8-bit or 16-bit timer that is dedicated to the support of both the asynchronous and synchronous EUSART operation. By default, the BRG operates in 8-bit mode. Setting the BRG16 bit of the BAUDCON register selects 16-bit mode.
The SPBRGH, SPBRGL register pair determines the period of the free running baud rate timer. In Asynchronous mode the multiplier of the baud rate period is determined by both the BRGH bit of the TXSTA register and the BRG16 bit of the BAUDCON register in order to Read Microcontroller ATTINY25 Flash. In Synchronous mode, the BRGH bit is ignored.