Low-Power Modes in Actel ProASIC3/E FPGAs
v1.1
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User Low Static (Idle) Mode
User Low Static (Idle) mode is an advanced feature supported by ProASIC3/E devices to reduce static
(idle) power consumption. Entering and exiting this mode is made possible using the ULSICC macro
by setting its value to disable/enable the User Low Static (Idle) mode. Under typical operating
conditions, characterization results show up to 25% reduction of the static (idle) power
consumption. The greatest power savings in terms of percentage are seen in the smaller members
of the ProASIC3 family. The active-high control signal for User Low Static (Idle) mode can be
generated by internal or external logic. When the device is operating in User Low Static (Idle)
mode, FlashROM functionality is temporarily disabled to save power. If FlashROM functionality is
needed, the device can exit User Low Static mode temporarily and re-enter the mode once the
functionality is no longer needed.
in your design, and connect the input port to either an internal logic signal or a device package
used so the Synplify synthesis tool will not optimize the instance with no output port.
This mode can be used to lower standard static (idle) power consumption when the FlashROM
feature is not needed. Configuring the device to enter User Low Static (Idle) mode is beneficial
when the FPGA enters and exits static mode frequently and lowering power consumption as much
as possible is desired. The device is still functional, and data is retained in this state so the device
can enter and exit this mode quickly, resulting in reduced total power consumption. The device can
also stay in User Low Static mode when the FlashROM feature is not used in the device.
Figure 2-1 CCC/PLL Macro
CLKA
GLA
GLB
YB
GLC
YC
LOCK
POWERDOWN
OADIV[4:0]*
OAMUX[2:0]*
DLYGLA[4:0]*
OBDIV[4:0]*
OBMUX[2:0]*
DLYYB[4:0]*
DLYGLB[4:0]*
OCDIV[4:0]*
OCMUX[2:0]*
DLYYC[4:0]*
DLYGLC[4:0]*
FINDIV[6:0]*
FBDIV[6:0]*
FBDLY[4:0]*
FBSEL[1:0]*
XDLYSEL*
VCOSEL[2:0]*