Intel 386 - Manual (Page 298)

11-11
ASYNCHRONOUS SERIAL I/O UNIT
Figure 11-6. SIO n Data Reception Process Flow
A2525-02
Select the BCLKIN source and
the receiver input baud rate.
Select the data frame. (Word length,
number of stop bits, and type of
parity.) Enable interrupts and/or DMA.
Receiver shifts data into shift register
from the RXD
n pin.
Was
a break condition
detected?
Was
a framing error
detected?
Was
a parity error
detected?
Receiver sets the
parity error flag. Receiver sets
the break
interrupt flag.
Is
receive
buffer full flag
set?
Receiver transfers
data to receive
buffer and sets
overrun error flag.
Receiver transfers data to receive
buffer and sets receive buffer full
flag.
End
Receiver sets
the framing
error flag.
No No No
Yes Yes Yes
Yes
No
Service error
interrupt
(if enabled)
Service error
interrupt
(if enabled)
Any
error flags
set?
No
Yes