TMP89FW20AUG Datasheet, PDF (301/542 Pages) Toshiba Semiconductor – 8 Bit Microcontroller TLCS-870/C1 Series

TMP89FW20A
18.3 Low Power Consumption Function
UART0 has a low power consumption register (POFFCR1) that saves power consumption when the UART func-
tion is not used.
Setting POFFCR1<UART0EN> to "0" disables the basic clock supply to UART0 to save power. Note that this ren-
ders the UART unusable. Setting POFFCR1<UART0EN> to "1" enables the basic clock supply to UART0 and ren-
ders the UART usable.
After reset, POFFCR1<UART0EN> is initialized to "0", and this renders the UART unusable. When using the
UART for the first time, be sure to set POFFCR1<UART0EN> to "1" in the initial setting of the program (before
the UART control register is operated).
Do not change POFFCR1<UART0EN> to "0" during the UART operation, otherwise UART0 may operate unex-
pectedly.
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