EP3C16F256I7N Altera, EP3C16F256I7N Datasheet - Page 321

• Manufacturer Part Number: EP3C16F256I7N
• Description: Cyclone III
• Manufacturer: Altera

Altera Corporation-Preliminary
March 2007
ACTIVE_ENGAGE
The new instruction ACTIVE_ENGAGE enables you to "re-engage" an
already disengaged active controller. You can issue this instruction any
time (during configuration or user mode) and it will "re-engage" an
already disengaged active controller as well as trigger reconfiguration of
the Cyclone III device in active mode specified by MSEL pin settings.
It will act as PULSE_NCONFIG instruction when the device is in passive
configuration schemes (PS, or FPP). The nCONFIG pin is disabled when
the ACTIVE_ENGAGE instruction is issued.
Overriding the Internal Oscillator
This feature allows you to override the internal oscillator during active
configuration. The active configuration (AS, and AP) controllers use the
internal oscillator as the clock source. You can change the clock source to
CLKUSR through JTAG instruction.
The JTAG instructions EN_ACTIVE_CLK and DIS_ACTIVE_CLK will
toggle on or off whether the active clock is sourced from the CLKUSR pin
or the internal configuration oscillator. To source the active clock from the
CLKUSR pin, you can issue the EN_ACTIVE_CLK instruction. This will
cause the CLKUSR pin to become the active clock source. Normally, test
instruments use this when it wants to drive its own clock to control the
AS state machine.
To revert the clock source back to the configuration oscillator, you can
issue the DIS_ACTIVE_CLK instruction. Consequently, a power-on reset
(POR) will revert the clock source back to the configuration oscillator.
Toggling the nCONFIG pin or driving the JTAG state machine to the Reset
state will not revert the clock source.
Table 10–19
clock.
Notes to
(1)
Minimum
TBD
Table 10–19. CLKUSR Input Frequency for Active Clock
These values are preliminary.
Table
shows the CLKUSR input frequency range for the active
10–19:
Typical
TBD
Cyclone III Device Handbook, Volume 1
Maximum
TBD
Cyclone III JTAG Instructions
Note (1)
Units
TBD
10–85