LFXP20E-4F484C Lattice, LFXP20E-4F484C Datasheet - Page 308

• Manufacturer Part Number: LFXP20E-4F484C
• Description: IC FPGA 19.7KLUTS 340I/O 484-BGA
• Manufacturer: Lattice

Specifications of LFXP20E-4F484C

• Lead Free Status / Rohs Status: Contains lead / RoHS non-compliant

Lattice Semiconductor
LatticeXP sysCONFIG Usage Guide
ispJTAG Pins
The ispJTAG pins are standard IEEE 1149.1 TAP (Test Access Port) pins. The ispJTAG pins are dedicated pins and
are always accessible when the LatticeXP device is powered up. When programming the SRAM via ispJTAG the
dedicated programming pins, such as DONE, cannot be used to determine programming progress. This is because
the state of the boundary scan cell will drive the pin, per JTAG 1149.1, rather than normal internal logic.
TDO
The Test Data Output pin is used to shift out serial test instructions and data. When TDO is not being driven by the
internal circuitry, the pin will be in a high impedance state.
TDI
The Test Data Input pin is used to shift in serial test instructions and data. An internal pull-up resistor on the TDI pin
is provided. The internal resistor is pulled up to V
CCJ.
TMS
The Test Mode Select pin controls test operations on the TAP controller. On the falling edge of TCK, depending on
the state of TMS, a transition will be made in the TAP controller state machine. An internal pull-up resistor on the
TMS pin is provided. The internal resistor is pulled up to V
CCJ.
TCK
The test clock pin, TCK, provides the clock to run the TAP controller, which loads and unloads the data and instruc-
tion registers. TCK can be stopped in either the high or low state and can be clocked at frequencies up to the fre-
quency indicated in the device data sheet. The TCK pin supports the value is shown in the DC parameter table of
the data sheet. The TCK pin does not have a pull-up. A pull-down on the PCB of 4.7 K is recommended to avoid
inadvertent clocking of the TAP controller as V
ramps up.
CC
Optional TRST
Test Reset, TRST, in not supported on the LatticeXP device.
VCCJ
JTAG V
(V
) supplies independent power to the JTAG port to allow chaining with other JTAG devices at a com-
CC
CCJ
mon voltage. V
must be connected even if JTAG is not used. This voltage may also power the JTAG download
CCJ
cable. Valid voltage levels are 3.3V, 2.5V, 1.8V, 1.5V, and 1.2V.
Please see In-System Programming Design Guidelines for ispJTAG Devices, available on the Lattice web site at
www.latticesemi.com, for further JTAG chain information.
Configuration and JTAG Voltage Levels
All of the control pins and programming pins default to LVCMOS. CFG and PROGRAMN are linked to V
(core);
CC
TCK, TDI, TDO, and TMS track V
; all other pins track the V
for that pin.
CCJ
CCIO
Configuration Modes and Options
The LatticeXP device supports several configuration modes, utilizing serial or parallel data inputs, as well as self-
configuration. On power up, or upon driving the PROGRAMN pin low, the CFG[1:0] pins are sampled to determine
the mode that will be used to configure the LatticeXP device. The CFG pins are generally hard wired on the PCB
and determine which port the device will use to retrieve its configuration data. CONFIG_MODE is a programmable
option accessed via preferences in Lattice ispLEVER design software, or as HDL source file attributes, and allow
the user to protect the configuration pins from accidental use by the user or the place-and-route software.
Table 13-7 shows the mode, CFG[1:0], and the software CONFIG_MODE parameter. The following sections break-
down each configuration mode.
13-9