HP E2470A, Manual

Page: 27 / 71

Table 2-2 MC68HC16Y1 Symbolic Representation of Status Bits
Label Symbol Status
Encoding
Cycle Type
Opcode Fetch
(internal)
(external)
x x x 2 H or
x x x A H
x x x 3 H or
x x x B H
Data Read
(internal)
(external)
x x x 6 H or
x x x E H
x x x 7 H or
x x x F H
Data Write
(internal)
(external)
x x x 4 H or
x x x C H
x x x 5 H or
x x x D H
Size of Transfer
Byte Transfer (8 bit) x x 1 x H
Word Transfer (16 bit) x x 2 x H
3-Byte Transfer (24 bit) x x 3 x H
Long Word Transfer (32 bit) x x 0 x H
The logic analyzer captures prefetches, even if they are not executed. Care
must be taken when specifying a trigger condition or a storage qualification that
follows an instruction that may cause branching. An unused prefetch may
generate an unwanted trigger.
Since the microcontroller only prefetches at most two words, one technique
to avoid unwanted triggering from unused prefetches is to add "4" to the
trigger address. This trigger condition will only be satisfied if the branch is
not taken.
Analyzing the Motorola MC68HC16Y1
To display the configuration labels and symbols
2–6