Baud Rate Of The External Clock (One-To-One Mode) - Fujitsu MB90335 Series Hardware Manual

MB90335 Series
18.6.3

Baud Rate of the External Clock (One-to-one Mode)

Indicates the formula for the settings and the baud rates for selecting the external clock,
as UART transfer clock. It is used in the clock synchronous modes.
■ Baud Rate of the External Clock (One-to-one Mode)
Selecting the baud rate of external clock (one-to-one mode) requires the following three settings.
Write "0" in MD bit of UART prescaler control registers 0, 1 (UTCR0, UTCR1), and "1" to CKS bit, and
select the baud rate resulting from the external clock (one-to-one mode).
Set SCK0, SCK1 pins to Enter (DDR4: bit4=0, bit7=0).
Write "0" in SCKE bit of the serial mode registers 0, 1 (SMR0, SMR1) to define the pin as external clock
input pin.
It is used in the synchronous modes.
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Calculation expression for baud rate
When the baud rate resulting from the external clock (one-to-one mode) is selected (UTCR0, UTCR1:
MD=0, CKS=1), resulted baud rate is as follows (f for the frequency of the external clock).
Synchronous = f (bps)
f: External clock frequency
However, the maximum of f is up to 1/8 of the machine clocks.
CM44-10137-6E FUJITSU MICROELECTRONICS LIMITED
CHAPTER 18 UART
18.6 UART Baud Rate
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