13.19.6.2.3.1 Asynchronous Arithmetic Mode BAUD Value Selection

The formula given for f_BAUD calculates the average frequency over 65536 f_ref cycles. Although the BAUD register can be set to any value between 0 and 65536, the actual average frequency of f_BAUD over a single frame is more granular. The BAUD register values that will affect the average frequency over a single frame lead to an integer increase in the cycles per frame (CPF)

$CPF=\frac{f_{ref}}{f_{BAUD}}(D+S)$

where

• D represent the data bits per frame
• S represent the sum of start and first stop bits, if present.

Table 13-55 shows the BAUD register value versus baud frequency f_BAUD at a serial engine frequency of 48MHz. This assumes a D value of 8 bits and an S value of 2 bits (10 bits, including start and stop bits).