Chapter 9: Configuration, Design Security, and Remote System Upgrades in the Cyclone III Device Family
Configuration Features
9–61
I/O Reconfiguration
Use the
CONFIG_IO
instruction to reconfigure the I/O configuration shift register
(IOCSR) chain. This instruction allows you to perform board-level testing prior to
configuring the Cyclone III device family or waiting for a configuration device to
complete configuration. After the configuration is interrupted and JTAG testing is
complete, the part must be reconfigured using the
PULSE_NCONFIG
JTAG instruction
or by pulsing the
nCONFIG
pin low.
You can issue the
CONFIG_IO
instruction any time during user mode. The
CONFIG_IO
instruction cannot be issued when
nCONFIG
pin is asserted low (during power up) or
immediately after issuing a JTAG instruction that triggers reconfiguration. For more
information about the wait-time for issuing the
CONFIG_IO
instruction, refer to
When using
CONFIG_IO
instruction, you must meet the following timing restrictions:
■
■
CONFIG_IO
instruction cannot be issued during the
nCONFIG
pin low
Observe 230
s
minimum wait time after any of the following conditions are met:
■
■
■
nCONFIG
pin goes high
Issuing the
PULSE_NCONFIG
instruction
Issuing the
ACTIVE_ENGAGE
instruction, before issuing the
CONFIG_IO
instruction
■
Wait 230
s
after power up with
nCONFIG
pin high before issuing the
CONFIG_IO
instruction (or wait for the
nSTATUS
pin to go high)
Table 9–18. Wait Time for Issuing the CONFIG_IO Instruction
Wait Time
Wait time after the
nCONFIG
pin is released
Wait time after
PULSE_NCONFIG
or
ACTIVE_ENGAGE
is
issued
Time
230
s
230
s
Use the
ACTIVE_DISENGAGE
instruction with
CONFIG_IO
instruction to interrupt
configuration.
lists the sequence of instructions to use for various
CONFIG_IO
usage scenarios.
Table 9–19. JTAG CONFIG_IO (without JTAG_PROGRAM) Instruction Flows
(Part 1 of 2)
Configuration Scheme and Current State of the Cyclone III Device Family
Prior to User Mode
(Interrupting
Configuration)
PS
FACTORY
ACTIVE_DISENGAGE
CONFIG_IO
JTAG Boundary Scan Instructions (no
JTAG_PROGRAM)
NA
O
R
O
FPP
NA
O
R
O
AS
NA
O
R
O
AP
JTAG Instruction
User Mode
AP
Power Up
AP
PS
NA
O
R
O
FPP
NA
O
R
O
AS
NA
O
R
O
PS
R
—
NA
—
FPP AS
R
—
NA
—
R
—
NA
—
NA
O
R
O
NA
O
R
O
NA
—
NA
—
August 2012
Altera Corporation
Cyclone III Device Handbook
Volume 1
ALTERA [ ALTERA CORPORATION ]
