Functional-Level Operation - HP 3000 Series Installation And Service Manual

Principles of Operation
parallel frcm the INP Microprocessor and convert them into a con-
tinuous serial stream for transrnissicn. Simultaneously, they can
receive a serial stream of data and control infcrmaticn and
assemble it into a series of parallel data bytes fer the INP
Mier op rocessor.
4-7. Communication Line Interfaces
The communication line interfaces,
Direct-connect, etc., translate
signals that are electrically and
the re si;:.ect i ve standards.
4-8. FUNCTIONAL-LEVEL OPERATION
such as RS2 32C, Bell DCS,
data and control lines intc
mechanically compatible with
In the following typical message transmission sequence, a moderr
telephone line is assumed as the ccrr,murdcations medium. Refer-
ences are made to the functional areas, data paths, and service
request. paths within the block diagram in figure
4-1. The data paths and service request paths being referenced
are identified in the diagram by circled numbers.
Injtially, the HP
3000
has been powered up, and the previously
attachEd communication line is net yet operational. ThE precess
of powering up invokes the ROM-resident control program. The
contrcl program both resets the INP logic and verifies INP oper-
a t ion . Th E· res u 1 ts of the ope r a t ion ve r if i ca t ion a r e a va
i l
ab le
tc the HP
300C
on request.
To initiate transmission, the system issues a central oaraweter
over the MUX bus tc the HP
3000
Interface of the INP, ( 1) This
action causes an interrupt bit to be set, (2) , which interrupts
the INP Microprocessor, ( 3) The INP Microprocessor then reads
the interrupt register, (4) , to determine which device is
rec;uesting service. Next, the INP Microproces.sor interrcgateE.
the HP
30
0 0 I n t e r face , ( 5 } , to de t e rm i ne the n a t u r e of the
service being requested (new control word, neK data wcrd, etc.).
In this example, the control word read in (5) tells the INF
microprocessor to start transferring data words frcm the HP
30CC
Interface to the INP RAM fer local buffering. Typically, the INP
reads a whole buffer or block from the HP
3000
before beginring
to transfer data over the data communication line.
The flows frcm the HP
30CO
into memory are represented by (6) and
(7) in figure 4-1. Upon receiving a full block, the INP Micro-
processor raises R'rS, (8) , and sets up an interrupt for when thE
mcdem returns CTS.
vffien
errs
becomes active, an interrupt is
generated to the INP Microprocessor, (9) The INP
~icro­
processcr then sends data frorr the INP RAM to the datacomm
4-4
JUN 1980