Sio N Data Transmission Process Flow - Intel 386 User Manual

Intel386™ EX EMBEDDED MICROPROCESSOR USER'S MANUAL
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Yes
Data to
Transmit
?
No
Figure 11-4. SIO n Data Transmission Process Flow
11-8
Select the BCLKIN source and
the transmitter input baud rate.
Select the data frame. (Word length, number
of stop bits, and type of parity.) Enable interrupts
and/or DMA.
Is
transmit buffer
empty?
Yes
Write data to transmit buffer register.
(ISR or DMA cycle)
Transmitter transfers data to shift register
and sets transmit buffer empty flag, causing
an interrupt or DMA request.
Transmitter shifts data frame onto
the TXD n pin. Data is transmitted
least-significant bit first.
Transmitter shifts out last stop bit
then sets the transmitter empty flag.
End
No
A2527-02