33.6.2.3.1 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)

C P F = \frac{f_{r e f}}{f_{B A U D}} (D + S)

where

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

Table 33-3 shows the BAUD register value versus baud frequency f_BAUD at a serial engine frequency of 48 MHz. This assumes a D value of 8 bits and an S value of 2 bits (10 bits, including start and stop bits).

Table 33-3. BAUD Register Value vs. Baud Frequency
BAUD Register Value	Serial Engine CPF	f_BAUD at 100MHz Serial Engine Frequency (f_REF)
0 – 406	161	6.211 MHz
407 – 808	162	6.211 MHz
809 – 1205	163	6.173 MHz
...	...	...
65206	31775	31.47 kHz
65207	31872	31.38 kHz
65208	31969	31.28 kHz