Chapter 9: Configuration, Design Security, and Remote System Upgrades in the Cyclone III Device Family
9–61
Configuration Features
I/O Reconfiguration
Use the CONFIG_IOinstruction 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 nCONFIGpin low.
You can issue the CONFIG_IOinstruction any time during user mode. The CONFIG_IO
instruction cannot be issued when nCONFIGpin 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_IOinstruction, refer to
Table 9–18.
When using CONFIG_IOinstruction, you must meet the following timing restrictions:
■
■
CONFIG_IOinstruction cannot be issued during the nCONFIGpin low
Observe 230 s minimum wait time after any of the following conditions are met:
■
■
■
nCONFIGpin goes high
Issuing the PULSE_NCONFIGinstruction
Issuing the ACTIVE_ENGAGEinstruction, before issuing the CONFIG_IOinstruction
■
Wait 230 s after power up with nCONFIGpin high before issuing the CONFIG_IO
instruction (or wait for the nSTATUSpin to go high)
Table 9–18. Wait Time for Issuing the CONFIG_IO Instruction
Wait Time
Time
Wait time after the nCONFIG pin is released
230 s
Wait time after PULSE_NCONFIGor ACTIVE_ENGAGEis
issued
230 s
Use the ACTIVE_DISENGAGEinstruction with CONFIG_IOinstruction to interrupt
configuration. Table 9–19 lists the sequence of instructions to use for various
CONFIG_IOusage scenarios.
(1)
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
User Mode
Power Up
JTAG Instruction
Configuration)
AP
AP
AP
PS FPP
AS
PS
FPP
AS
PS FPP AS
(4)
(4)
(4)
FACTORY
NA
O
NA
O
NA
O
NA
O
NA
O
NA
O
NA
O
NA
O
R
R
R
NA
—
ACTIVE_DISENGAGE
—
—
—
CONFIG_IO
R
R
R
R
R
R
R
R
NA NA NA NA
JTAG Boundary Scan Instructions (no
O
O
O
O
O
O
O
O
—
—
—
—
JTAG_PROGRAM
)
August 2012 Altera Corporation
Cyclone III Device Handbook
Volume 1
ALTERA [ ALTERA CORPORATION ]
