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JTAG-SMT2
Programming Module for Xilinx® FPGAs
Revised March 2, 2015
DOC#: 502-251
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 1 of 11
1
2
3
4 8
9
10
11
5
6
7
GND
TCK
TDI
TMS
GPIO1
GPIO2
GPIO0
TDO
VREF
GND
Vdd (3.3V)
Small, complete, all-in-one JTAG programming/debugging
solution for Xilinx FPGAs
Compatible with all Xilinx Tools
Compatible with IEEE 1149.7-2009 Class T0 – Class T4
(includes 2-Wire JTAG)
GPIO pin allows debugging software to reset the processor
core of Xilinx’s Zynq® platform
Single 3.3V supply
Separate Vref drives JTAG signal voltages; Vref can be any
voltage between 1.8V and 5V.
High-Speed USB2 port that can drive JTAG/SPI bus at up to
30Mbit/sec (frequency settable by user)
SPI programming solution (modes 0 and 2 up to 30Mbit/sec,
modes 1 and 3 up to 2Mbit/sec)
Uses micro-AB USB2 connector
Small form-factor surface-mount module can be directly
loaded on target boards
A similar circuit is available as a stand-alone programming
cable; see Digilent’s JTAG-HS2.
Features include:
Overview
The Joint Test Action Group (JTAG)-SMT2 is a compact, complete and fully self-contained surface-mount
programming module for Xilinx field-programmable gate arrays (FPGAs). The module can be accessed directly from
all Xilinx Tools, including iMPACT, Chipscope™, and EDK. Users can load the module directly onto a target board
and reflow it like any other component.
The JTAG-SMT2 uses a 3.3V main power supply and a separate Vref supply to drive the JTAG signals. All JTAG
signals use high speed, 24mA, three-state buffers that allow signal voltages from 1.8V to 5V and bus speeds of up
to 30MBit/sec. The JTAG bus can be shared with other devices as systems hold JTAG signals at high-impedance,
except when actively driven during programming. The SMT2 module is CE certified and fully compliant with EU
RoHS and REACH directives. The module uses a standard Type-A to Micro-USB cable available for purchase from
Digilent, Inc.
Users can connect JTAG signals directly to the corresponding FPGA signals, as shown in Fig. 1. For best results,
mount the module adjacent to the edge of the host PCB over a ground plane. Although users may run signal traces
on top of the host PCB beneath the SMT2, Digilent recommends keeping the area immediately beneath the SMT2
clear.
Note: Keep the impedance between the SMT2 and FPGA below 100 Ohms to operate the JTAG at maximum speed.
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 2 of 11
TCK
JTAG-SMT2 FPGA
TMS
TDI
TDO
GND
VREF
VIO
TMS
TCK
TDI
TDO
3.3V
V
IO
GND
Vdd
USB2
Port
2
4
3
8
1
9
11
TCK
JTAG-SMT2 FPGA
TMS
TDI
TDO
GND
VREF
VIO
SS
SCK
MOSI
MISO
3.3V
V
IO
GND
Vdd
USB2
Port
2
4
3
8
1
9
11
Chip Select
Signal
Port
Number
SPI
Mode
Shift
LSB
First
Shift
MSB
First
Selectable
SCK
Frequency
Max SCK
Frequency
Min SCK
Frequency
Inter-byte
Delay
TMS/CS0
0
0
Yes
Yes
Yes
30 MHz
8 KHz
0 – 1000 µS
2
Yes
Yes
Yes
30 MHz
8 KHz
0 – 1000 µS
1
0
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
1
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
2
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
3
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
GPIO0/CS1
2
0
Yes
Yes
Yes
30 MHz
8 KHz
0 – 1000 µS
2
Yes
Yes
Yes
30 MHz
8 KHz
0 – 1000 µS
3
0
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
1
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
2
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
3
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
GPIO1/CS2
4
0
Yes
Yes
Yes
30 MHz
8 KHz
0 – 1000 µS
2
Yes
Yes
Yes
30 MHz
8 KHz
0 – 1000 µS
5
0
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
1
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
2
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
3
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
GPIO2/CS3
6
0
Yes
Yes
Yes
30 MHz
8 KHz
0 – 1000 µS
2
Yes
Yes
Yes
30 MHz
8 KHz
0 – 1000 µS
7
0
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
1
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
2
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
3
Yes
Yes
Yes
2.066 MHz
485 KHz
0 – 1000 µS
Figure 1. JTAG-SMT2 port connections.
The SMT2 improves upon the SMT1 with the addition of three general purpose IO pins (GPIO0 – GPIO2) and
support for interfacing IEEE 1149.7-2009 JTAG targets in both 2 and 4-wire modes.
In addition to supporting JTAG, the JTAG-SMT2 also features eight highly configurable Serial Peripheral Interface
(SPI) ports that allow communication with virtually any SPI peripheral (see Fig. 2). All eight SPI ports share the
same SCK, MOSI, and MISO pins, so users may enable only one port at any given time. Table 1 summarizes the
features supported by each port. The HS2 supports SPI modes 0, 1, 2, and 3.
JTAG-SMT2 Reference Manual
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Other product and company names mentioned may be trademarks of their respective owners.
Page 3 of 11
TMS
TDI
TCK
TDO
Host
+
JTAG-SMT2
(DTS)
TMS
TDI
TCK
TDO
Target
System 0
TMS
TDI
TCK
TDO
Target
System 1
TMS
TDI
TCK
TDO
Target
System N
Figure 3. 4-Wire series topology.
Note: The Xilinx Tools expect GPIO2/CS3 to be connected to the SRST_B pin on a Zynq chip. As a result, SPI ports 6
and 7 may not be used for SPI communication if the Xilinx Tools are going to be used to communicate with the
SMT2.
Software Support
In addition to working seamlessly with all Xilinx Tools, Digilent’s Adept software and the Adept software
development kit (SDK) support the SMT2 module. For added convenience, customers may freely download the
SDK from Digilent’s website. This Adept software includes a full-featured programming environment and a set of
public application programming interfaces (API) that allow user applications to directly drive the JTAG chain.
With the Adept SDK, users can create custom applications that will drive JTAG ports on virtually any device. Users
may utilize the APIs provided by the SDK to create applications that can drive any SPI device supporting those
modes. Please see the Adept SDK reference manual for more information.
IEEE 1149.7-2009 Compatibility
The JTAG-HS2 supports several scan formats, including the JScan0-JScan3, MScan, and OScan0 - OScan7. It is
capable of communicating in 4-wire and 2-wire scan chains that consist of Class T0 – T4 JTAG Target Systems (TS)
(see Figs. 3 & 4).
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 4 of 11
2-Wire Star Topology
TMSC
TDIC
TCKC
TDOC
Target
System 0
Target
System 1
Target
System N
TMSC
TDIC
TCKC
TDOC
TMSC
TDIC
TCKC
TDOC
TMS
TDI
TCK
TDO
Host
+
JTAG-SMT2
(DTS)
VREF
Output Pin
(TMS, TDI, TCK)
100K
JtagEN
VREF
Input Pin
(TDO)
100K
TMSC
TDIC
TCKC
TDOC
Target
System 0
Target
System 1
Target
System N
4-Wire Star Topology
TMSC
TDIC
TCKC
TDOC
TMSC
TDIC
TCKC
TDOC
TMS
TDI
TCK
TDO
Host
+
JTAG-SMT2
(DTS)
Figure 4. 4-Wire and 2-Wire star topology.
Figure 5. Pull-ups on TMS, TDI, TDO, and TCK signals.
The IEEE 1149.7-2009 specification requires any device that functions as a debug and test system (DTS) to provide
a pull-up bias on the TMS and TDO pins. In order to meet this requirement, the JTAG-SMT2 features weak pull-ups
(100K ohm) on the TMS, TDI, TDO, and TCK signals. Though not required in the specifications, the pull-ups on the
TDI and TCK signals ensure that neither signal floats while another source is not driving them (see Fig. 5).
Users should place a current limiting resistor between the TMS pin of the SMT2 and the TMSC pin of the TS when
using the JTAG-SMT2 to interface with an 1149.7 compatible TS. If a drive conflict occurs, this resistor should
prevent damage to components by limiting the amount of current flowing between the pins of each device. A 200
ohm resistor will limit the maximum current to 16.5mA when using a 3.3V reference (see Figs. 6 & 7). While this
level of resistance should be sufficient for most applications, the value of the resistor may need to be adjusted to
meet the requirements of the TS.
In most cases users can avoid a drive conflict by having applications that use the SMT2 communicate with the TS in
two-wire mode. Use the applications to reconfigure the TS to use the JScan0, JScan1, JScan2, or JScan3 scan
format prior to disabling the SMT2’s JTAG port.
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 5 of 11
VIO
1149.7
Target
System
TDOC
TMSC
TDIC
TCKC
GND
VDD
VREF
TDO
JTAG-
SMT2
GND
TMS
TDI
TCK
VIO
3.3V
VIO
200
VIO
1149.7
Target
System
TDOC
TMSC
TDIC
TCKC
GND
VDD
VREF
TDO
JTAG-
SMT2
GND
TMS
TDI
TCK
VIO
3.3V
VIO
200
IO Pin
(GPIO0, GPIO1, GPIO2)
100K
VREF
OEGPIOx
Figure 6. Adding a current limiting resistor.
Figure 7. 200 Ohm resistor limiting current flow.
Figure 8. GPIO signals.
The Adept SDK provides an example application that demonstrates how to communicate with a Class T4 TAP
controller using the MScan, OScan0, and OScan1 scan formats.
GPIO Pins
The JTAG-SMT2 has three general purpose IO pins (GPIO0, GPIO1, and GPIO2) that are useful for a variety of
different applications. Each pin features high speed, three-state input and output buffers. At power up, the JTAGSMT2 disables these output buffers and places the signals in a high-impedance state. Each signal remains in a
high-impedance state until a host application enables DPIO port 0 and configures the applicable pin as an output.
When the host application disables DPIO port 0, all GPIO pins revert to a high-impedance state. Weak pull-ups
(100K ohm) ensure that the GPIO signals do not float while not being actively driven (see Fig. 8).
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 6 of 11
VCCO_0
VCCO_MIO1
PS_SRST_B
ZYNQ-
7000
TDO
TMS
TDI
TCK
GND
VDD
VREF
TDO
JTAG-
SMT2
GND
TMS
TDI
TCK
GPIO0
GPIO1
GPIO2
VCCO
3.3V
VCCO
Figure 9. Connecting the JTAG-SMT2 to Xilinx’s Zynq-7000.
When customers use the JTAG-SMT2 to interface the scan chain of Xilinx’s Zynq platform, they should connect the
GPIO2 pin of the SMT2 to the Zynq’s PS_SRST_B pin. This connection allows the Xilinx Tools to reset the Zynq’s
processor core at various times during debugging operations. Please see the following “Application Examples”
section for more information.
Note: The Xilinx tools expect GPIO2 to be connected to the SRST_B pin on a Zynq chip. As a result, GPIO2 may not be
used as a general purpose I/O if the Xilinx Tools are going to be used to communicate with the SMT2.
Note: DPIO port 0 can only be used while both JTAG and SPI are disabled.
Application Examples
Example 1:
Interfacing a Zynq-7000 when VCCO_0 and VCCO_MIO1 use a common supply
Figure 9demonstrates how to connect the JTAG-SMT2 to Xilinx’s Zynq-7000 silicon when the same voltage supplies
both the VCCO_0 (Programmable Logic Bank 0 Power Supply) and the VCCO_MIO1 (Processor MIO Bank 1 Power
Supply).
In this case the SMT2 has a 100K pull-up to VREF, which operates at the same voltage as VCCO_MIO1. This similar
voltage makes it possible to eliminate the external pull-up that is normally required for the PS_SRST_B pin.
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 7 of 11
VCCO_0
VCCO_MIO1
PS_SRST_B
ZYNQ-
7000
TDO
TMS
TDI
TCK
GND
VDD
VREF
TDO
JTAG-
SMT2
GND
TMS
TDI
TCK
GPIO0
GPIO1
GPIO2
VCCO_0
VCCO_MIO1
3.3V
VCCO_0
VCCO_MIO1
10K
Optional Reset
Button
Figure 10. Use of an open drain buffer.
Example 2:
Interfacing a Zynq-7000 that uses different voltages for VCCO_0 and VCCO_MIO1
Figure 10 demonstrates how to connect the JTAG-SMT2 to Xilinx’s Zynq-7000 silicon when different voltages
supply the VCCO_0 (Programmable Logic Bank 0 Power Supply) and VCCO_MIO1 (Processor MIO Bank 1 Power
Supply). If the Zynq’s JTAG pins are operating at a different voltage than the PS_SRST_B, it requires an external
buffer to adjust the level of the GPIO2 signal. The example in Fig. 10 demonstrates the use of an open drain buffer
to allow for the possibility of adding a reset button.
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 8 of 11
VCCO_0
VCCO_MIO1
PS_SRST_B
ZYNQ-
7000
TDO
TMS
TDI
TCK
GND
VDD
VREF
TDO
JTAG-
SMT2
GND
TMS
TDI
TCK
GPIO0
GPIO1
GPIO2
VCCO_0
VCCO_MIO1
3.3V
VCCO_0
VCCO_MIO1
10K
Optional Reset
Button
VCCO_MIO1
10K
VCCO_0
VCCO_0
100
100
100
50
Xilinx JTAG
Header
1 2
3 4
5 6
7 8
9
10
11 12
13
14
Jumper
Figure 11. Open drain buffers allowing the SMT2 and JTAG Header to drive the PS_SRST_B pin.
Example 3:
Interfacing a Zynq-7000 while retaining the Xilinx JTAG Header
Figure 11 below demonstrates how to connect the JTAG-SMT2 to Xilinx’s Zynq-7000 silicon alongside Xilinx’s 14-pin
JTAG header. In this example the open drain buffers allow both the SMT2 and Xilinx JTAG Header to drive the
PS_SRST_B pin, which may operate a different voltage than the Zynq’s JTAG pins.
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 9 of 11
11 10 9
1 2 3 4
22.75mm
21.5mm
3mm
5mm
2mm
4mm
Pads on bottom
PCB surface
8
6 5
5mm
2mm
5.75mm
7
SMT2 Top View
Symbol
Parameter
Condition
Min
Max
Unit
Vdd
Operating supply voltage
-0.3
4.0
V
Vref
I/O reference/supply voltage
-0.3
6
V
VIO
Signal Voltage
-0.3
6
V
IIK,IOK
TMS, TCK, TDI, TDO, GPIO0, GPIO1,
GPIO2
DC Input/Output Diode Current
VIO < -0.3V
-50
mA
VIO > 6V
+20
I
OUT
DC Output Current
±50
mA
T
STG
Storage Temperature
-20
+120
ºC
ESD
Human Body Model JESD22-A114
4000
V
Charge Device Model JESD22-C101
2000
V
2 3 41
9 81011
3.5mm
3.0mm
5mm
4mm
19.5mm
PCB Edge
Recommended PCB Land Pattern
15mm
5
21.75mm
67
3.0mm
3.5mm
4.75mm5mm
2.6mm
2.2mm
6.2mm
2.6mm
2.2mm
6.2mm
Electrical
Keepout
2.45
mm
Electrical
Keepout
Mechanical Information
Absolute Maximum Ratings
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 10 of 11
Symbol
Parameter
Min
Typ
Max
Unit
Vdd
Operating supply voltage
2.97
3.3
3.63
Volts
Vref
I/O reference/supply voltage
1.65
2.5/3.3
5.5
Volts
TDO, GPIO0,
GPIO1, GPIO2
Input High Voltage (VIH)
1.62 5.5
Volts
Input Low Voltage (VIL)
0 0.65
Volts
TMS, TCK, TDI,
GPIO0, GPIO1,
GPIO2
Output High (VOH)
0.85 x Vref
0.95 x Vref
Vref
Volts
Output Low (VOL)
0
0.05 x Vref
0.15 x Vref
Volts
TA
Operating Temperature
0 70
ºC
Symbol
Parameter
Min
Max
TCK
TCK period
33ns
2.185ms
T
CKH
, T
CKL
T
CLK
pulse width
20ns
1.1ms
TCD
T
CLK
to TMS, TDI
0
15ns
TSU
TDO Setup time
19ns
THD
TDO Hold time
0
Figure 12. Timing diagram.
TMS/TDI
TCK
TDO
T
CKL
T
CKH
T
CK
T
CD
T
SU
T
HD
Table 2. JTAG frequency support.
DC Operating Characteristics
AC Operating Characteristics
The JTAG-SMT2’s JTAG signals operate according to the timing diagram in Fig. 12. The SMT2 supports JTAG/TCK
frequencies from 30 MHz to 8 KHz at integer divisions of 30 MHz from 1 to 3750. Common frequencies include 30
MHz, 15 MHz, 10 Mhz, 7.5 MHz, and 6 MHz (see Table 2). The JTAG/TCK operating frequency can be set within the
Xilinx Tools. Note: Please refer to Xilinx’s iMPACT documentation for more information.
Mounting to Host PCBs
The JTAG-SMT2 module has a moisture sensitivity level (MSL) of 6. Prior to reflow, the JTAG-SMT2 module must be
dried by baking it at 125° C for 17 hours. Once this process has been completed, the module has a MSL of 3 and is
suitable for reflow for up to 168 hours without additional drying.
The factory finishes the JTAG-SMT2 signal pads with the ENIG process using 2u” gold over 150u” electroless nickel.
This makes the SMT2 compatible with most mounting and reflow processes (see Fig. 13). The binding force of the
solder is sufficient to hold the SMT2 firmly in place so mounting should require no additional adhesives.
JTAG-SMT2 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 11 of 11
Limit time above
205°C to less
than 110s
35cm
28cm
Figure 13.JTAG-SMT2 reflow temperature over time.
Figure 14. JTAG-SMT2 shipping arrangement.
Packaging
Digilent ships small quantities of less than 20 per order individually packaged in antistatic bags. Digilent will pack
and ship larger quantities in groups of 80 positioned in an antistatic bubble tray (see Fig. 14).
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