The following setup was used for Basys2 board with an external FTDI-based JTAG adapter. Read the previous posts to get familiar with setup.
Specifying USERCODE
User code register provides bit stream identification and a type of version control. To write a user code into a bit stream in Xilinx ISE, go to "Implementation" -> "Design" and right-click on "Generate Programming File". In the popped up window specify your 32-bit user code in hexadecimal format:
For example, I set it to 0xADEAFBEE. Now generate the *.bit file in Xilinx ISE and analyze its header using bitparse utility, which is a part of xc3sprog:
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[johndoe@ArchLinux]% bitparse Sliding_LED.bit Created from NCD file: Sliding_LED.ncd;UserID=0xADEAFBEE Target device: 3s100ecp132 Created: 2017/01/26 17:53:30 Bitstream length: 581344 bits 72668 bytes(0x011bdc) 64-bit sum: 18460515 |
UserID field tells that its value is embedded into the bit stream and will be written to the USERCODE during configuration.
Now program the FPGA using xc3sprog:
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[johndoe@ArchLinux]% xc3sprog -c ft232h Sliding_LED.bit XC3SPROG (c) 2004-2011 xc3sprog project $Rev: 785 $ OS: Linux Free software: If you contribute nothing, expect nothing! Feedback on success/failure/enhancement requests: http://sourceforge.net/mail/?group_id=170565 Check Sourceforge for updates: http://sourceforge.net/projects/xc3sprog/develop Using Libftdi, |
Reading USERCODE in UrJTAG
While your program is running on the FPGA, run UrJTAG:
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[johndoe@ArchLinux]% jtag UrJTAG 0.10 #2052 Copyright (C) 2002, 2003 ETC s.r.o. Copyright (C) 2007, 2008, 2009 Kolja Waschk and the respective authors UrJTAG is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. There is absolutely no warranty for UrJTAG. warning: UrJTAG may damage your hardware! Type "quit" to exit, "help" for help. jtag> cable ft2232 vid=0x0403 pid=0x6014 Connected to libftd2xx driver. jtag> bsdl path Basys2_BSDL jtag> detect IR length: 14 Chain length: 2 Device Id: 11110101000001000101000010010011 (0xF5045093) Filename: Basys2_BSDL/xcf02s.bsd Device Id: 00010001110000010000000010010011 (0x11C10093) Filename: Basys2_BSDL/xc3s100e_cp132.bsd jtag> print chain No. Manufacturer Part Stepping Instruction Register ------------------------------------------------------------------------------------------------------------------- 0 XCF02S BYPASS BYPASS * 1 XC3S100E_CP132 BYPASS BYPASS jtag> instruction USERCODE jtag> shift ir jtag> shift dr jtag> dr 10101101111010101111101111101110 (0xADEAFBEE) jtag> |
The USERCODE instruction selects USERCODE register as data register. Shifting 32 bits into the data register will yield our user code.
Reading USERCODE in OpenOCD
While your program is running on the FPGA, start OpenOCD server:
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[johndoe@ArchLinux]% openocd -f OpenOCD/FT232H.cfg -f OpenOCD/Basys2.cfg Open On-Chip Debugger 0.10.0 Licensed under GNU GPL v2 For bug reports, read http://openocd.org/doc/doxygen/bugs.html adapter speed: 6000 kHz xc3s_get_dna Info : clock speed 6000 kHz Info : JTAG tap: prom.tap tap/device found: 0xf5045093 (mfg: 0x049 (Xilinx), part: 0x5045, ver: 0xf) Info : JTAG tap: spartan3e.tap tap/device found: 0x11c10093 (mfg: 0x049 (Xilinx), part: 0x1c10, ver: 0x1) Warn : gdb services need one or more targets defined |
In other terminal, connect as a client:
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[johndoe@ArchLinux]% telnet localhost 4444 Trying ::1... Connection failed: Connection refused Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. Open On-Chip Debugger > scan_chain TapName Enabled IdCode Expected IrLen IrCap IrMask -- ------------------- -------- ---------- ---------- ----- ----- ------ 0 prom.tap Y 0xf5045093 0xf5045093 8 0x01 0x03 1 spartan3e.tap Y 0x11c10093 0x11c10093 6 0x01 0x03 > irscan spartan3e.tap 0x08 # USERCODE instruction opcode > drscan spartan3e.tap 0x20 0 # 32 in hexadecimal, state 0 ADEAFBEE > |
The user code is successfully retrieved.