HIPPI
S2020/S2021 SOURCE DEVICE STATE MACHINES
HOST DATA/FIFO SM INPUTS
EXTERNAL INPUTS
{IDLE} The IDLE state is entered from the {DISCON0-
2'} state sequence, the {INTRPKT} state or the
{ENDBPKT} state if the “IDLG” decode is true. In
addition to the standard transitions, this state is ex-
ited to the {HSEQER} state if the “DXFR” decode is
true, to {ILLINPT} if the “HIFL” decode is true, and
to the {BGNPKT} state if the “GLRC” decode is
true. In this pre- and inter-packet state the general
op status word is presented on the data outputs of
the Destination device.
BRST BuRST signal from the HIPPI channel. The
functions of this signal are defined in the HIPPI-PH
spec.
PKT PacKeT signal from the HIPPI channel. The func-
tions of this signal are defined in the HIPPI-PH
spec.
4.1.2 INTERNAL INPUTS
{BGNPKT} The BeGiN PacKeT state is entered from
the {IDLE} state, the {INTRPKT} state or the
{ENDBPKT} state if the “GLRC” decode is true. In
addition to the standard transitions, this state is ex-
ited to the {HSEQER} if the “IDLG” decode is true,
to the {ILLINPT} state if the “HIFL” decode is true,
to the {PKTNBST} state if the “GLRC” decode is
true, and to the {DTATRNSF} state if the “DXFR”
decode is true. In this state the general op status
word is presented on the data outputs of the Desti-
nation device.
<NXTST6> State 6 signal from the Connect Control
SM: This signal is active when the Connect Control
SM is in the {REQCON} state. This signal indicates
the reception of an I-Field’ from the HIPPI channel.
<NXTST25> State 25 signal from the Connect Control
SM: This signal is active when the Connect Control
SM is in the {CONNECTED} state. This signal al-
lows the Data/FIFO SM to process Packet and
Burst delimited data from the HIPPI channel.
4.2 HOST DATA/FIFO SM INTERNAL
STATES
{PKTNBST} The PacKeT No BurST state is entered
from the {BGNPKT} state if the “GLRC” decode is
true. This state persists if the “GLRC” decode re-
mains true. In addition to the standard transitions,
this state is exited to the {HSEQER} state if the
“IDLG” decode is true, to the {ILLINPT} state if the
“HIFL” decode is true, and to the {DTATRNSF}
state if the “DXFR” decode is true. In this state the
general op status word is presented on the data
outputs of the Destination device.
The defined states of the Data/FIFO SM are as follows:
{DISCON0-2} The DISCONnected 0 through
DISCONnected 2 states are repetitively sequenced
if the “DISC” input decode is true. This sequence is
entered at {DISCON0} if the Mode 0 Reset is com-
manded via the MSEL0-2 inputs. While in this Se-
quence, the Idle/Disabled status word, the flow
status word 1, and the flow status word 2 are pre-
sented in sequence on the data outputs of the Des-
tination device. In addition to the standard
transitions, this state sequence is exited to the
{HSEQER} state if the “GLRC” or “DXFR” decodes
are true, to the {IFIELD} state if the “HIFL” decode
is true, or to the {IDLE} state if the “IDLG” decode is
true.
{DTATRNSF} The DaTA TRaNSFer state is entered
from the {BGNPKT} state, the {PKTNBST} state , or
the {IBSTGP} state if the “DXFR” decode is true.
this state persists if the “DXFR” decode remains
true. In this state Burst data is received and pre-
sented to the data outputs of the Destination de-
vice. In addition to the standard transitions, this
state is exited to the {HSEQER} state if the “IDLG”
decode is true, to the {ILLINPT} state if the “HIFL”
decode is true, or to the {LLRCCH} state if the
“GLRC” decode is true.
{IFIELD} The I-FIELD state’ is entered from the
{DISCON0-2} state sequence if the “HIFL” decode
is true. This state persists if the “HIFL” decode re-
mains true. In addition to the standard transitions,
this state is exited to {HSEQER} if the “GLRC” or
“DXFR” decodes are true or to the {ILLINPT} state
if the “IDLG” decode is true. The normal functional
exit is the standard “DISC” to {DISCON0}. In this
state the received I-Field from the HIPPI channel is
presented on the data outputs of the Destination
device.
{LLRCCH} The LLRC CHaracter state is entered from
the {DTATRNSF} state if the “GLRC” decode is
true. In this state the received LLRC character from
the HIPPI channel is presented on the data outputs
of the Destination device. During this state, the in-
ternally calculated LLRC character is compared to
the received character and the result of this com-
parison is presented one clock cycle later on the
RLLER output of the Destination device. In addition
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