Xilinx Virtex-4 - Configuration Control Logic; Packet Types; Type 1 Packet

88 www.xilinx.com Virtex-4 FPGA Configuration User Guide
UG071 (v1.12) June 2, 2017
Chapter 7: Configuration Details
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Configuration Control Logic
The Virtex-4 configuration logic consists of a packet processor, a set of registers, and global
signals that are controlled by the configuration registers. The packet processor controls the
flow of data from the configuration interface (SelectMAP, JTAG, or Serial) to the
appropriate register. The registers control all other aspects of configuration.
Packet Types
The FPGA bitstream consists of two packet types: Type 1 and Type 2. These packet types
and their usage are described below.
Type 1 Packet
The Type 1 packet is used for register reads and writes. Only 5 out of 14 register address
bits are used in Virtex-4 FPGAs. The header section is always a 32-bit word.
Following the Type 1 packet header is the Type 1 Data section, which contains the number
of 32-bit words specified by the word count portion of the header. See Table 7-2 and
Table 7-3.
XC4VSX25 440 6,940 7,380 41 284,540 1312
XC4VSX35 660 10,410 11,070 41 426,810 1312
XC4VSX55 1,104 17,304 18,408 41 709,464 1312
XC4VFX12 248 3,600 3,848 41 147,600 1312
XC4VFX20 360 5,488 5,848 41 225,008 1312
XC4VFX40 660 10,296 10,956 41 422,136 1312
XC4VFX60 1,040 15,976 17,016 41 665,016 1312
XC4VFX100 1,660 25,170 26,830 41 1,031,970 1312
XC4VFX140 2,424 36,444 38,868 41 1,494,204 1312
Notes:
1. Non-configuration frames should be considered when calculating T
PL
(Program Latency) but do not contribute to the bitstream size.
See Table 41: Configuration Switching Characteristics in the Virtex-4 FPGA Data Sheet.
2. Configuration frames contribute to both the T
PL
calculation and the overall bitstream size.
3. The number of device frames equals the number of non-configuration plus configuration frames, and is the number of frames to use
when calculating T
PL
.
4. All Virtex-4 configuration frames consist of 41 32-bit words.
5. Configuration array size equals the number of configuration frames times the number of words per frame.
6. Configuration overhead consists of commands in the bitstream that are needed to perform configuration, but do not themselves
program any memory cells. Configuration overhead contributes to the overall bitstream size.
Table 7-1: Virtex-4 Frame Count, Frame Length, Overhead and Bitstream Size (Continued)
Device
Non-Configuration
Frames
(1)
Configuration
Frames
(2)
Device
Frames
(3)
Frame Length
(words)
(4)
Configuration
Array Size
(words)
(5)
Configuration
Overhead
(words)
(6)