Digi NS9750 - Manual (Page 669)

w w w . d i g i e m b e d d e d . c o m 6 4 5
S e r i a l C o n t r o l M o d u l e : S P I
Bit-rate generator
Each serial channel supports an independent programmable bit-rate generator. The
bit-rate generator runs both the transmitter and receiver of a given channel (there is
no split speed support).
You can configure the bit-rate generator to use external clock input or internal
system timing as its timing reference. This allows for a wider range of possible bit-
rates.
Table 380 describes all possible clock reference sources used by the bit-rate
generator.
Name Description
BCLK The clock source for all peripherals that are attached to the BBus. The frequency of
BCLK is the AHB clock frequency divided by 2.
ExtRxClk External receive clock on GPIO pins gpio[6], gpio[14], gpio[22], and gpio[26] for
serial ports B, A, C, and D, respectively.
ExtTxClk External transmit clock on GPIO pins gpio[7], gpio[15], gpio[23], and gpio[27] for
serial ports B, A, C, and D, respectively.
Table 380: Bit-rate generation clock sources