FPGA
MEN Mikro Elektronik GmbH
86
20A014-00 E2 – 2007-08-16
3.2.2.2
Identification Word and Configuration Table
The address space of the FPGA starts with an identification word and a
configuration table. The identification word (BAR0; address
0x0000
) describes the
FPGA configuration by a character (A to Z) and its revision number. Byte 0 at
address
0x0000
contains the revision number, byte 1 at address
0x0001
contains
the describing character in ASCII format.
Example: address
0x0000
Ö
identification word
0x4103
Ö
variant A3
In the FPGA address space the identification word is followed by the configuration
table which gives detailed information about the implemented modules.
The Magic Word at address
0x0004
is used by software to identify the
configuration table.
It is possible to use different Base Address Registers of the PCI Configuration
Space. (This is necessary for modules which require an address space larger than
256 bytes.) If other BARs are used, the module's memory space which is allocated
with the BARs other than BAR 0 has other base addresses as viewed from the PCI
bus. Inside the board’s FPGA the module's address space starts at
0x0000
too, but
all modules are enabled by a chip select signal generated in consideration of the
used BAR.
A separate Base Address Register (apart from BAR 0) can be used e.g. to access
memory. This simplifies PCI host accesses to that module because the memory's
address always starts at
0x0000
. The PCI host must access the FPGA with the
correct base address only.
To provide the information which modules are implemented, the FPGA
configuration table contains two binary words for each module to code module
information such as
• Device
• Revision
• Used Base Address Register
• Number of instance
• Used interrupt line for that device
• Start address in A14C memory space
You can find an overview and descriptions of all available FPGA IP cores on MEN’s
website
.
Chapter 3.3 Standard Factory FPGA Configuration on page 92
gives an example
configuration, including a configuration table.