ACEX 1K Programmable Logic Device Family Data Sheet
In addition to the six clear and preset modes, ACEX 1K devices provide a
chip-wide reset pin that can reset all registers in the device. Use of this
feature is set during design entry. In any of the clear and preset modes, the
chip-wide reset overrides all other signals. Registers with asynchronous
presets may be preset when the chip-wide reset is asserted. Inversion can
be used to implement the asynchronous preset. Figure 12 shows examples
of how to setup the preset and clear inputs for the desired functionality.
Figure 12. ACEX 1K LE Clear & Preset Modes
Asynchronous Clear
Asynchronous Preset
Asynchronous Preset & Clear
labctrl1
VCC
PRN
Chip-Wide Reset
labctrl1 or
PRN
D
Q
labctrl2
D
Q
PRN
D
Q
CLRN
CLRN
labctrl1 or
labctrl2
labctrl2
Chip-Wide Reset
CLRN
Chip-Wide Reset
VCC
Asynchronous Load without Clear or Preset
Asynchronous Load with Clear
NOT
NOT
labctrl1
(Asynchronous
Load)
labctrl1
(Asynchronous
Load)
PRN
PRN
data3
(Data)
D
Q
data3
(Data)
D
Q
NOT
CLRN
CLRN
labctrl2
(Clear)
NOT
Chip-Wide Reset
Chip-WideReset
Asynchronous Load with Preset
NOT
labctrl1
(Asynchronous
Load)
labctrl2
(Preset)
PRN
D
Q
data3
(Data)
CLRN
NOT
Chip-Wide Reset
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