Specifications

270 www.xilinx.com Embedded System Tools Guide (EDK 6.2i)
1-800-255-7778 UG111 (v1.4) January 30, 2004
Chapter 16: Microprocessor Peripheral Description (MPD)
R
An unconnected port is identified as an empty double-quote (““) string.
The EDK tools resolves the driver value on unconnected input ports by the INITIALVAL
keyword.
Format
PORT mysignal = “”, DIR=OUTPUT
Scalable Data path
Using an MPD keyword declaration, you can automatically scale data path width. Bus
expressions are evaluated as arithmetic equations.
Format
PORT name = default_connection, VEC=[A:B]
Where A and B are positive integer expressions.
MPD Example
The following is an example MPD file:
BEGIN my_peripheral
# Generics for vhdl or parameters for verilog
PARAMETER C_BASEADDR = 0xB00000, DT=std_logic_vector(0 to 31)
PARAMETER C_MY_PERIPH_AWIDTH = 17, DT=integer
# Global ports
PORT OPB_Clk = “”, DIR=I
PORT OPB_Rst = “”, DIR=I
# My peripheral signals
PORT MY_ADDR = “”, DIR=O, VEC=[0:C_MY_PERIPH_AWIDTH-1]
# OPB signals
.
.
END
By default, if the vectors are larger than one bit, EDK tools determine the range
specification on buses as either big-endian or little-endian. However, if the vector is one-bit
width, then the range cannot be determined, and the EDK tools default to big-endian style
notation.
To change this default behavior, use the ENDIAN keyword.
Format
PORT mysignal = “”, DIR=I, VEC=[0:0], ENDIAN=LITTLE
This builds the VHDL equivalent:
mysignal: in std_logic_vector(0 downto 0);
Interrupt Signals
Interrupt signals are identified by the SIGIS=INTERRUPT name-value keyword.