9–62
Chapter 9: Configuration, Design Security, and Remote System Upgrades in the Cyclone III Device Family
Configuration Features
Table 9–19. JTAG CONFIG_IO (without JTAG_PROGRAM) Instruction Flows
(1)
(Part 2 of 2)
Configuration Scheme and Current State of the Cyclone III Device Family
Prior to User Mode
(Interrupting
Configuration)
PS
ACTIVE_ENGAGE
PULSE_NCONFIG
Pulse
nCONFIG
pin
JTAG TAP Reset
Notes to
(1) “R” indicates that the instruction is to be executed before the next instruction, “O” indicates the optional instruction, “A” indicates that the
instruction must be executed, and “NA” indicates that the instruction is not allowed in this mode.
(2) Required if you use
ACTIVE_DISENGAGE.
(3) Neither of the instruction is required if you use
ACTIVE_ENGAGE.
(4) AP configuration is for Cyclone III devices only.
JTAG Instruction
User Mode
AP
(4)
Power Up
AP
(4)
FPP
AS
R
AP
(4)
PS
FPP
AS
R
PS
—
—
—
—
FPP AS
—
—
—
—
—
—
—
—
R
A
A
R
—
—
—
—
A
R
A
R
A
A
A
R
A
R
O
O
R
O
O
R
R
R
The
CONFIG_IO
instruction does not hold the
nSTATUS
pin low until reconfiguration.
You must disengage the active configuration controllers (AS and AP) by issuing the
ACTIVE_DISENGAGE
and
ACTIVE_ENGAGE
instructions when the active configuration is
interrupted. You must issue the
ACTIVE_DISENGAGE
instruction alone or prior to the
CONFIG_IO
instruction if the
JTAG_PROGRAM
instruction is to be issued later (Table
This puts the active configuration controllers into the idle state. The active
configuration controller is re-engaged after user mode is reached using JTAG
programming (Table
1
While executing the
CONFIG_IO
instruction, all user I/Os are tri-stated.
If reconfiguration after interruption is performed using configuration modes (rather
than using
JTAG_PROGRAM),
it is not necessary to issue the
ACTIVE_DISENGAGE
instruction prior to
CONFIG_IO.
You can start reconfiguration by either pulling the
nCONFIG
pin low for at least 500 ns, or issuing the
PULSE_NCONFIG
instruction. If the
ACTIVE_DISENGAGE
instruction was issued and the
JTAG_PROGRAM
instruction fails to
enter user mode, you must issue the
ACTIVE_ENGAGE
instruction to reactivate the active
configuration controller. Issuing the
ACTIVE_ENGAGE
instruction also triggers the
reconfiguration in configuration modes; therefore, it is not necessary to pull the
nCONFIG
pin low or issue the
PULSE_NCONFIG
instruction.
ACTIVE_DISENGAGE
The
ACTIVE_DISENGAGE
instruction places the active configuration controller (AS and
AP) into an idle state prior to JTAG programming. The active configuration controller
is the AS controller when the MSEL pins are set to AS configuration scheme and the
AP controller when the MSEL pins are set to the AP configuration scheme. The two
purposes of placing the active controllers in an idle state are:
■
To ensure that they are not trying to configure the device in their respective
configuration modes during JTAG programming
Cyclone III Device Handbook
Volume 1
August 2012 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
