
CTM
REFERENCE
MOTOROLA
8-13
DOUBLE ACTION SUBMODULE (DASM)
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8
8.5
Freeze action on the DASM
When the IMB FREEZE signal is recognized, the DASM captures and compares functions are
halted. As soon as the FREEZE signal is negated, DASM actions resume as if nothing had
happened. During freeze, the IN bit of the DASMSIC register is readable and returns the level
present at the input pin if an input mode is selected, or the output value if an output mode is in
operation. When one of the output modes is in operation, the force output function remains
available, allowing the software to output the desired level and simplifying debugging. All DASM
registers are accessible during freeze.
8.6
DASM registers
The DASM register map comprises four 16-bit register locations. As shown in Table 8-3, the
register block contains three DASM registers and one reserved register. All unused bits and
reserved address locations return zero when read by the software. Writing to unused bits and
reserved address locations has no meaning nor effect. All register addresses in this section are
specified as offsets from the base address of the DASM. In CTM implementations featuring
multiple DASMs, each DASM has its own set of registers.
(1) Offset fromthe base address of the DASMsubmodule.
Table 8-3
DASM register map
Address
(1)
$00
$02
$04
$06
15
8 7
0
DASMstatus/interrupt/control register (DASMSIC)
DASMregister A (DASMA)
DASMregister B (DASMB)
F
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