Altera USB-Blaster II - Manual (Page 16)

2–6 Chapter 2: USB-Blaster II Download Cable Specifications
JTAG Timing Constraints and Waveforms
USB-Blaster II Download Cable October 2014 Altera Corporation
User Guide
To use the USB-Blaster II at the maximum capability (24 MHz), meet the timing
constraints (
Table 2–6 ) for the target device.
The timing constraints require that you consider device specifications as well as trace
propagation delays. If you do not follow the recommended constraints, you might
encounter timing issues at 24 MHz. If the target design cannot meet these constraints,
reduce the possibility of timing issues by slowing the TCK frequency. See
“Changing
the TCK Frequency” on page 2–7 for instructions on running the USB-Blaster II at a
slower speed.
1
The simulated timing is based on a slow timing model, which is a worst-case scenario
environment.
f For device-specific JTAG timing information, refer to the related device data sheet
available from the
http://www.altera.com/literature/lit-index.html web page.
Table 2–6. JTAG Timing Constraints for the Target Device
Symbol Parameter Min Max Unit
tJCP TCK clock period 41.67 — ns
tJCH TCK clock high time 20.83 — ns
tJCL TCK clock low time 20.83 — ns
tJPCO JTAG port clock to JTAG Header output —
5.46 (2.5 V)
2.66 (1.5 V)
ns
tJPSU_TDI JTAG port setup time (TDI) — 24.42 ns
tJPSU_TMS JTAG port setup time (TMS) — 26.43 ns
tJPH JTAG port hold time — 17.25 ns