Baud Rate Of The External Clock Using The Dedicated Baud Rate Generator - Fujitsu MB90335 Series Hardware Manual

CHAPTER 18 UART
18.6 UART Baud Rate
18.6.2 Baud Rate of the External Clock Using the Dedicated
Baud Rate Generator
Indicates baud rates possible to set when a dedicated baud rate generator of an
external clock is selected, as UART transfer clock. It is used in the asynchronous
modes.

■ Baud Rate of the External Clock Using the Dedicated Baud Rate Generator

Divides the clock by setting the 11-bit reload value at the UART prescaler control registers 0, 1 (UTCR0,
UTCR1), and the UART prescaler reload registers 0, 1 (UTRLR0, UTRLR1).
Provided f for the frequency of the external clock, baud rates are described as follows:
• UTCR0, UTCR1: If MD is set to "1".
b= f/4n (bps), f≤ φ × n/4
f: Frequency of the external clock, n: Values of D10 to D0 (UTCR0, UTCR1, UTRLR0, UTRLR1),
b: Baud rate
However, please set neither n=1, 2 nor 3.
Maximum frequency of f is 24 MHz.
Note:
Errors is occurred to the calculation value of baud rate because baud rate generated by the external
clock is synchronized with the machine clock.
412 FUJITSU MICROELECTRONICS LIMITED
MB90335 Series
CM44-10137-6E