HW-USBN-2A Datasheet, PDF (3/7 Pages) Lattice Semiconductor – ispDOWNLOAD Cables For Programming Lattice ISP Devices

Lattice Semiconductor
ispDOWNLOAD Cables
Target Board Design Considerations
A 4.7K pull-down resistor is recommended on the TCK connection of the target board. This pull-down is recom-
mended to avoid inadvertent clocking of the TAP controller induced by fast clock edges or as Vcc ramps up. This
pull-down is recommended for all Lattice programmable families.
Programming Flywire and Connection Reference
Refer to Table 2 when connecting a flywire download cable to systems that use the 1x8-position or 2x5-position
connectors. For newer Lattice FPGA families, a 1x10 connector used in conjunction with the ispDOWNLOAD USB
cable adds support for the DONE and INITN signals. Both of these signals are inputs to the cable, and can be used
to help verify device configuration.
Table 2. Flywire Conversion Reference
Function
Flywire Cable
1x10 Connector
1x8 Connector
2x5 Connector
V_CC¹
TDO/SDO
Red
1
1
6
Brown
2
2
7
TDI/SDI
Orange
3
3
5
ispEN²/Enable/PROGRAMN
Yellow
4
4
10
TRST³
Green
5
5
9
TMS/MODE
Purple
6
6
3
GND
Black
7
7
4 (2 and 8)
TCK⁴/SCLK
White
8
8
1
DONE³
Green
9
INITN
Blue
10
1. For devices that have a V_CCJ pin, the V_CCJ must be connected to the cable’s V_CC, and a 0.1µF decoupling capacitor is required on V_CCJ
close to the device. Please refer to the device data sheet to determine if the device has a V_CCJ pin.
2. For older Lattice ISP devices, a 0.01µF decoupling capacitor is required on ispEN/ENABLE of the target board.
3. The TRST and DONE pin is multiplexed on the ispDOWNLOAD USB cable. If the device TRST signal is available on the board, connect the
USB flywire TRST/DONE wire to TRST. If the device DONE signal is available on the board (or if both TRST and DONE are available), con-
nect the USB flywire TRST/DONE wire to DONE. Please make sure the correct setting is selected in ispVM (Options, Cable and I/O Port
Setup). This will tell ispVM whether the TRST/DONE cable is used as a TRST or a DONE signal.
4. A 4.7K pull-down resister is recommended on TCK of the target board.
Table 3 lists the recommend pin connections. Please contact Lattice technical support for information on unlisted
device families. (e-mail: [e-mail], phone: 1-800-LATTICE).
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