Chapter 2: Device Datasheet for Cyclone V Devices
2–39
Glossary
Table 2–43. Glossary Table (Part 3 of 4)
Letter
Subject
Definitions
Timing Diagram—the period of time during which the data must be valid in order to capture
it correctly. The setup and hold times determine the ideal strobe position within the sampling
window, as shown:
Sampling window
(SW)
Bit Time
Sampling Window
(SW)
RSKM
RSKM
0.5 x TCCS
0.5 x TCCS
The JEDEC standard for the SSTl and HSTL I/O defines both the AC and DC input signal
values. The AC values indicate the voltage levels at which the receiver must meet its timing
specifications. The DC values indicate the voltage levels at which the final logic state of the
receiver is unambiguously defined. After the receiver input has crossed the AC value, the
receiver changes to the new logic state.
The new logic state is then maintained as long as the input stays beyond the AC threshold.
This approach is intended to provide predictable receiver timing in the presence of input
waveform ringing, as shown:
S
Single-Ended Voltage Referenced I/O Standard
Single-ended
voltage
VCCIO
referenced I/O
standard
VOH
VIH
(
)
AC
VIH(DC)
VREF
VIL(DC)
VIL(AC
)
VOL
VSS
tC
High-speed receiver/transmitter input and output clock period.
The timing difference between the fastest and slowest output edges, including the tCO
variation and clock skew, across channels driven by the same PLL. The clock is included in
the TCCS measurement (refer to the Timing Diagram figure under SW in this table).
TCCS (channel-
to-channel-skew)
High-speed I/O block—Duty cycle on high-speed transmitter output clock.
Timing Unit Interval (TUI)
tDUTY
The timing budget allowed for skew, propagation delays, and the data sampling window.
T
(TUI = 1/(Receiver Input Clock Frequency Multiplication Factor) = tC/w)
tFALL
Signal high-to-low transition time (80-20%)
Cycle-to-cycle jitter tolerance on the PLL clock input
Period jitter on the general purpose I/O driven by a PLL
Period jitter on the dedicated clock output driven by a PLL
Signal low-to-high transition time (20–80%)
—
tINCCJ
tOUTPJ_IO
tOUTPJ_DC
tRISE
U
—
February 2012 Altera Corporation
Cyclone V Device Handbook
Volume 1: Device Overview and Datasheet
ALTERA [ ALTERA CORPORATION ]
