M1A3P250-VQ100 Datasheet, PDF (114/210 Pages) Microsemi Corporation – ProASIC3 Flash Family FPGAs with Optional Soft ARM Support

Pin Descriptions
If the JTAG interface is neither used nor planned for use, the VJTAG pin together with the TRST pin
could be tied to GND.
It should be noted that VCC is required to be powered for JTAG operation; VJTAG alone is insufficient. If
a device is in a JTAG chain of interconnected boards, the board containing the device can be powered
down, provided both VJTAG and VCC to the part remain powered; otherwise, JTAG signals will not be
able to transition the device, even in bypass mode.
Microsemi recommends that VPUMP and VJTAG power supplies be kept separate with independent
filtering capacitors rather than supplying them from a common rail.
VPUMP
Programming Supply Voltage
ProASIC3 devices support single-voltage ISP of the configuration flash and FlashROM. For
programming, VPUMP should be 3.3 V nominal. During normal device operation, VPUMP can be left
floating or can be tied (pulled up) to any voltage between 0 V and the VPUMP maximum. Programming
power supply voltage (VPUMP) range is listed in Table 2-2 on page 2-2.
When the VPUMP pin is tied to ground, it will shut off the charge pump circuitry, resulting in no sources of
oscillation from the charge pump circuitry.
For proper programming, 0.01 µF and 0.33 µF capacitors (both rated at 16 V) are to be connected in
parallel across VPUMP and GND, and positioned as close to the FPGA pins as possible.
Microsemi recommends that VPUMP and VJTAG power supplies be kept separate with independent
filtering capacitors rather than supplying them from a common rail.
User Pins
I/O
User Input/Output
The I/O pin functions as an input, output, tristate, or bidirectional buffer. Input and output signal levels are
compatible with the I/O standard selected.
During programming, I/Os become tristated and weakly pulled up to V_CCI. With V_CCI, VMV, and V_CC
supplies continuously powered up, when the device transitions from programming to operating mode, the
I/Os are instantly configured to the desired user configuration.
Unused I/Os are configured as follows:
• Output buffer is disabled (with tristate value of high impedance)
• Input buffer is disabled (with tristate value of high impedance)
• Weak pull-up is programmed
GL
Globals
GL I/Os have access to certain clock conditioning circuitry (and the PLL) and/or have direct access to the
global network (spines). Additionally, the global I/Os can be used as regular I/Os, since they have
identical capabilities. Unused GL pins are configured as inputs with pull-up resistors.
See more detailed descriptions of global I/O connectivity in the "Clock Conditioning Circuits in IGLOO
and ProASIC3 Devices" chapter of the ProASIC3 FPGA Fabric User’s Guide. All inputs labeled GC/GF
are direct inputs into the quadrant clocks. For example, if GAA0 is used for an input, GAA1 and GAA2
are no longer available for input to the quadrant globals. All inputs labeled GC/GF are direct inputs into
the chip-level globals, and the rest are connected to the quadrant globals. The inputs to the global
network are multiplexed, and only one input can be used as a global input.
Refer to the I/O Structure section of the handbook for the device you are using for an explanation of the
naming of global pins.
FF
Flash*Freeze Mode Activation Pin
Flash*Freeze is available on IGLOO, ProASIC3L, and RT ProASIC3 devices. It is not supported on
ProASIC3/E devices. The FF pin is a dedicated input pin used to enter and exit Flash*Freeze mode. The
FF pin is active-low, has the same characteristics as a single-ended I/O, and must meet the maximum
rise and fall times. When Flash*Freeze mode is not used in the design, the FF pin is available as a
regular I/O. For IGLOOe, ProASIC3EL, and RT ProASIC3 only, the FF pin can be configured as a
Schmitt trigger input.
3-2
Revision 15