Coprocessor Reset; Coprocessor Summary - Motorola MC68020 User Manual

7.5.3 Coprocessor Reset

Either an external reset signal or a RESET instruction can reset the external devices of a
system. The system designer can design a coprocessor to be reset and initialized by both
reset types or by external reset signals only. To be consistent with the MC68020/EC020
design, the coprocessor should be affected by external reset signals only and not by
RESET instructions, because the coprocessor is an extension to the main processor
programming model and to the internal state of the MC68020/EC020.

7.6 COPROCESSOR SUMMARY

Coprocessor instruction formats are included with the instruction formats in the
M68000PM/AD, M68000 Family Programmer's Reference Manual .
The M68000 coprocessor response primitive formats are shown in this section. Any
response primitive with bits 13–8 = $00 or $3F causes a protocol violation exception.
Response primitives with bits 13–8 = $0B, $18–$1B, $1F, $28–$2B, and $38–3B currently
cause protocol violation exceptions; they are undefined and reserved for future use by
Motorola.
MOTOROLA M68020 USER'S MANUAL 7- 59