CD1865 Datasheet, PDF (85/150 Pages) Intel Corporation – Intelligent Eight-Channel Communications Controller

Intelligent Eight-Channel Communications Controller — CD1865
by hardware or software, the CD1865 does not initialize every register and RAM location to a
defined value. The only sure state is that all channels are inactive, no service requests are pending,
and the Global Interrupt Vector register is FF Hex.
Figure 28. Initialization
MASTER
CHIP
RESET
INITIALIZATION
GLOBAL
INITIALIZATION
GSVR
N
= FF
?
Y
LOAD GSVR WITH CHIP ID,
PILRS WITH VECTORS, AND
PRESCALE REGISTERS
LOAD CAR WITH A ‘0’
After either a hardware reset by the RESET pin or a software reset
by a CCR command, wait until the GSVR= xFF before proceeding
with chip initialization.
When the CD1865 is ready, begin by loading the GSVR with the
chip ID if there are more than one CD1865 in the system. Load
the Service Match registers with the vectors that will be used during
service acknowledge cycles. Load the Prescale registers with the
value chosen for the basic time count for timer operations.
In preparation for channel initialization, load the CAR with a ‘0’ to
access Channel Zero registers.
CCR
=0
N
?
Y
LOAD COR1-3 WITH
CHARACTER SETTINGS
AND OPERATION MODES
ISSUE COR CHANGE
COMMAND IN CCR
for the CCR to contain a value of zero to ensure that the
CD1865 is not processing a previous change command for that
channel.
Load the Channel Option registers with the values to enable the
desired modes of operation and character parameters such as
parity, stop bits, and so on.
Inform the CD1865 that one or more Channel Option registers
have changed via the COR Change Command.
CHANNEL LOAD SCHR1-3, MSVR,
INITIALIZATION _{MCOR1-2, TRANSMIT/RECEIVE}
INCREMENT CAR
Option registers for modem interrupt conditions; the MSVR with the
states of DTR/RTS as necessary and the baud rate constants for
Transmit and Receive Baud Rate Generators. Set the appropriate
bits in the SRER register for the interrupt conditions desired.
LAST
CHANNEL ^N
(CAR=8)
?
Y
DONE
If more channels, go back to the top of the loop.
Datasheet
85