43.24 UART AC Electrical Specifications

Table 43-30. UART AC Electrical Specifications

AC Characteristics

Standard Operating Conditions: V_DDIO = V_DDANA 1.9V to 3.6V (unless otherwise stated) Operating Temperature: -40°C ≤ T_A ≤ +85°C for Industrial Temp

-40°C ≤ T_A ≤ +125°C for Extended Temp

Param. No.

Symbol

Characteristics

Min.

Typ.

Max.

Units

Conditions

UT_1

F_BRATE

Baud rate

Asynchronous SAMPR = 16x mode

—

Asynchronous arithmetic formula⁽²⁾

Mbps

V_DDIO = 3.3V

UT_3

Asynchronous SAMPR = 8x mode

—

Asynchronous arithmetic formula⁽²⁾

Mbps

V_DDIO = 3.3V

UT_5

Asynchronous SAMPR = 3x mode

—

Asynchronous arithmetic formula⁽²⁾

Mbps

V_DDIO = 3.3V

UT_19

Synchronous mode

—

Synchronous formula⁽²⁾

Mbps

—

UT_23

F_USART

USART max GCLK_SERCOM

—

MHz

—

UT_25

F_XCK

USART external clock input

—

MHz

—

Note:

These parameters are characterized, but not tested in manufacturing.

Operating Mode	Condition	Baud Rate (Bits Per Second)	Baud Register Value Calculation
Asynchronous arithmetic	$f_{B A U D \leq \frac{f_{r e f}}{S}}$	$f_{B A U D = \frac{f_{r e f}}{S} (1 - \frac{B A U D}{65536})}$	$B A U D = 65536 . (1 - S . \frac{f_{B A U D}}{f_{r e f}})$
Synchronous	$f_{B A U D \leq \frac{f_{r e f}}{2}}$	$f_{B A U D \leq \frac{f_{r e f}}{2 . (B A U D + 1)}}$	$B A U D = \frac{f_{r e f}}{2 . f_{B A U D}} - 1$