7721 Datasheet, PDF (208/577 Pages) List of Unclassifed Manufacturers – H Bridge Power Module

SERIAL I/O
11.2 Block description
(1) Internal/External clock select bit (bit 3)
s Clock synchronous serial I/O mode
By clearing this bit to “0” in order to select an internal clock, the clock which is selected with the
BRG count source select bits (bits 0 and 1 at addresses 3416, 3C16) becomes the count source of
the BRGi (described later). The BRGi’s output divided by 2 becomes the transfer clock. Additionally,
the transfer clock is output from the CLKi pin.
By setting this bit to “1” in order to select an external clock, the clock input to the CLKi pin
becomes the transfer clock.
s UART mode
By clearing this bit to “0” in order to select an internal clock, the clock which is selected with the
BRG count source select bits (bits 0 and 1 at addresses 3416, 3C16) becomes the count source of
the BRGi (described later). Then, the CLKi pin functions as a programmable I/O port.
By setting this bit to “1” in order to select an external clock, the clock input to the CLKi pin
becomes the count source of BRGi.
Always in the UART mode, the BRGi’s output divided by 16 becomes the transfer clock.
7721 Group User’s Manual
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