702560 Spectrum Digital Inc, 702560 Datasheet - Page 26
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702560
Manufacturer Part Number
702560
Description
XDS560R USB JTAG Emulator With 20 Pin CTI JTAG Header
Manufacturer
Spectrum Digital Inc
Type
USB JTAG Emulatorr
Specifications of 702560
Contents
Board, Cable
Ic Product Type
USB JTAG Emulator
Kit Contents
XDS560R USB JTAG Emulator With CTI JTAG Header, CDROM With Drivers, USB Cable
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With/related Products
TI DSPs and JTAG Microcontrollers
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Spectrum Digital, Inc
3.4.1 Emulation Timing Calculations
3-8
The following examples help you calculate emulation timings in your system. For actual
target timing parameters, see the appropriate device data sheet.
Assumptions:
Given in Table 2 above:
There are two key timing paths to consider in the emulation design:
Equation 3-1. Key Timing Path Case 1
Case 1: Single processor, direct connection, TMS/TDI timed from TCK_RET high.
In this case, the TCK_RET-to-TDO path is the limiting factor.
t
t
t
t
T(
T
t
t
❏
❏
Of the following two cases (Equation 3-1 and Equation 3-2), the worst-case
path delay is calculated to determine the maximum system test clock
frequency.
t
t
su(TTMS)
pd(TTDO)
pd(bufmax)
pd(bufmin)
d(TMSmax)
su(TDOmin)
pd(TCK_RET - TMS/TDI)
pd(TCK_RET - TDO)
(TCKfactor)
bufskew)
The TCK_RET-to-TMS/TDI path, called t
The TCK_RET-to-TDO path, called t
= [ t
= [15 ns + 2.5 ns] / 0.4
= 43.75 ns (22.9 MHz)
Setup time, target TMS/TDI before TCK high
Delay time, TCK low to valid target TDO
Delay time, target buffer - maximum
Delay time, target buffer - minimum
Skew time, target buffer between two devices
in the same package:
40/60 clock duty cycle
Delay time, emulator TMS/TDI valid
from TCK_RET high
Setup time, TDO before emulator
TCK_RET high, minimum 2.5 ns
= 31 ns + 10 ns
= 41 ns (24.4 MHz)
= t
d(TTDO)
pd(TMSmax)
[ t
d(bufmax)
+ t
su(TDOmin)
XDS560R JTAG Emulator Installation Guide
+ t
-
t
d(bufmin)
su(TTMS)
pd(TCK_RET-TDO)
] / t
pd(TCK_RET-TMS/TDI)
] x 0.15
(TCKfactor)
.
10 ns
15 ns
10 ns
1 ns
1.35 ns
0.4(40%)
31 ns
2.5 ns
, and