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FUJITSU MB91460 SERIES FR60 User Manual

Page 680

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664

Chapter 32 USART (LIN / FIFO)

8.Notes on using USART

Baud Rate Detection Using the Input Capture Units

The USARTs provide the signal LSYN that can be connected to the ICU so that LSYN’s pulse length can be
measured to derive the baud rate. The connection of the LSYN signals to the ICUs is controlled by the Port 14
function register PFR and EPFR :

If the PFR bit equals ‘1’ and the EPFR bits equals ‘0’, the ICU is connected to its corresponding input pin IN.
If the PFR bit equals ‘1’ and the EPFR bits equals ‘1’, the USARTs are connected to the ICU.

The user has to take into account that:

• ICU4 and ICU5 share one free running timer (prescaler).

LIN-UART4

LSYN

ICU4

IN

ICU5

IN

FREE RUN TIMER4

Pin IN4

S

11

10

PFR[4] & EPFR[4]

S

11

10

Pin IN5

LIN-UART5

LSYN

PFR[5] & EPFR[5]