User`s guide

Data Structures and Memory Layout
C.1 Halt Dispatch State Machine
11 : halt
• User Action, specified with the SET HALT console command.
000 : default
001 : restart, halt
010 : boot, halt
011 : halt
100 : restart, boot, halt
• HEN, Break (halt) Enable/Disable switch, BDR<07>
• ERR, error status
• TIP, trace in progress
• DIP, diagnostics in progress
• BIP, bootstrap in progress CPMBX<2>
• RIP, restart in progress CPMBX<3>
A transition to a "next state" occurs if a match is found between the control
word and a "current state" entry in the table. The firmware does a linear
search through the table for a match. Therefore, the order of the entries in the
transition table is important. The control longword is reassembled before each
transition from the current machine state. The state machine transitions are
shown in Table C–1.
Table C–1 Firmware State Transition Table
Current
State
Next
State
Halt
Type
Halt
Code
Mailbx
Action
User
Action
HEN-ERR-TIP-
DIP-BIP-RIP
Perform conditional initialization
1
ENTRY –>RESET
INIT
xxx 01 xx xxx x - x - x - x - x - x
ENTRY –>BREAK
INIT
011 00 xx xxx x-x-x-x-x-x
ENTRY –>TRACE
INIT
xxx 10 xx xxx x - 0 - 1 - x - x - x
1
Perform a unique initialization routine on entry. In particular, power-ups, BREAKs, and TRACEs require
special initialization. Any other halt entry performs a default initialization.
(continued on next page)
C–2 Data Structures and Memory Layout