Pin and Signal Types

The Type column in the Pin List displays allowed pin types, such as IO, CLOCK, etc. Some types may be combined. For example, for differential clock pins DIFFCLOCK is displayed.

Table 8-1 lists the available pin and signal types. Unassignable pins have no associated HDL signal. Clock Capable I/O pairs are regular I/O pairs with special hardware connections to nearby regional clock resources.

Note
	For information on specific pins, refer to the vendor data sheet for the part.

Table 8-1. Pin and Signal Types

Pin Type	Description
AnalogTRTN	Unassignable temperature monitor return pin.
AnalogGND	Unassignable ground for an analog circuitry pin.
AnalogIO	Unassignable analog I/O pin.
AnalogPF	Unassignable analog power filter pin.
AnalogOFEP	Unassignable other front-end pin. (Actel only.)
AnalogVCC	Unassignable power for an analog circuitry pin.
AnalogVREF	Unassignable analog reference voltage pin.
CCLOCK	Assignable Clock Capable pin.
CCLOCKDIFF	Assignable differential Clock Capable pin.
CLOCK	Assignable clock pin (see Clock Assignments below).
CONFIG	Unassignable configuration pin.
DIFF	Assignable differential pin (see Clock Assignments below).
DIFFCLOCK	Assignable differential clock pin.
DQ	Assignable Double Data Rate memory interface data pin.
DQS	Assignable Double Data Rate memory interface data strobe pin.
DQSDIFF	Assignable Double Date Rate memory interface differential data strobe pin.
GND	Unassignable ground pin.
IO	Normal assignable pin.
JTAG	Unassignable JTAG pin.
MGT	Multi-Gigabit Transceiver pin.
MGTCALRES	Unasssignable MGT calibration resistor pin.
MGTCLK	Assignable differential reference clock of MGT pins.
MGTRX	Assignable MGT receiver pin.
MgtTerminationReference	Unassignable precision reference resistor pin.
MGTTX	Assignable MGT transmitter pin.
MGTVCC	Unassignable power-supply pin for transceiver mixed signal circuitry of the MGT.
MGTVCCAUX	Unassignable analog power supply pin for circuitry of the MGT.
MGTVCCIO	Unassignable power-supply pin for the MGT output drivers.
MGTVCCPLL	Unassignable power-supply pin for PLL MGT.
MGTVCCTRX	Unassignable input/output buffer power supply pin for channel on left or right side of device.
MGTVREF	Unassignable threshold voltage pin for MGT.
MGTVTTRXC	Unassignable power-supply pin for the resistor calibration circuit of the MGT.
MSS	Microcontroller subsystem pin. (Actel only.)
NC	Unassignable not connected pin.
OTHER	Unassignable pin of some other category.
PLL	Assignable phase-locked loops pin.
PLLCAP	Unassignable phase-locked loops capacitor pin.
PLLDIFF	Assignable differential phase-locked loops pin.
PowerManagement	Unassignable power management pin.
REFRES	Unassignable reference resistor pin.
RESERVED	Assignable pin with some additional features.
SystemMonitorADC	Unassignable system monitor pin.
TemperatureDiode	Unassignable temperate diode pin.
VBATT	Unassignable decrypter key memory backup supply pin.
VCC	Unassignable power pin.
VCCAUX	Unassignable power-supply pin for auxiliary circuits.
VCCINT	Unassignable dedicated internal core logic power supply pin.
VccMgtTermination	Unassignable power-supply pin for TX/RX circuitry of a transceiver.
VCCO	Unassignable power-supply pin for the output drivers.
VCCPD	Unassignable dedicated programming power supply pin.
VREF	Unassignable threshold voltage pin.
VTT	Unassignable dedicated terminating supply pin.

You can change the pin type for assigned pins, and change the default pin type for unassigned pins. Clicking inside the Type column presents a list containing all possible types for the selected pin. Changed pin types are stored in the database. Changes made to pin types are always associated with appropriate changes of the I/O Standards. It works the other way around too; if you switch a pin to an I/O Standard that does not support differential pins, the pin type is switched to non-differential.

In general, pin type usage is limited to what is hard-coded into the part libraries and allowed by pin assignment rules. For example; based on library data and a rule, you are not allowed to assign an output signal to a clock pin, since clock pins can be used only as input pins.