wecassidy / de0-cv_pins

Script to generate DE0-CV pin assignments

DE0-CV pin generator

The pin planner is slow and hard to use. This script automatically generates Quartus settings files that assign the pins from a simple INI file.

Example

Step 0: clone the repository

Suppose you want to make a 4-bit register on the DE0-CV in a Quartus project named "register". The project has three inputs named D (a four-line bus), CLK, and RST. There is one output Q, another 4-line bus. Planned connections:

• D → SW0 through SW3
• CLK → KEY0
• RST → KEY1
• Q → LEDR0 through LEDR3

First write a file describing the mappings, named pins.ini (or whatever you want, the file name doesn't matter):

[mapping]
D[0..3] = SW[0..3]
CLK = KEY0
RST = KEY1
Q[0..3] = LEDR[0..3]

The file is in INI format. The first line starts a section named mapping, and each line after that has the format node name = pin assignment. Notice how the D and Q buses are assigned; D[0..3] = SW[0..3] is equivalent to

D[0] = SW0
D[1] = SW1
D[2] = SW2
D[3] = SW3

Next, use the script to generate a Quartus settings file containing the pin assignments: on the command line, run python3 /path/to/script/pin_gen.py /path/to/pins.ini -o output.qsf. This will generate a file named output.qsf containing the following:

set_location_assignment PIN_U7 -to CLK
set_location_assignment PIN_W9 -to RST
set_location_assignment PIN_U13 -to D[0]
set_location_assignment PIN_V13 -to D[1]
set_location_assignment PIN_T13 -to D[2]
set_location_assignment PIN_T12 -to D[3]
set_location_assignment PIN_AA2 -to Q[0]
set_location_assignment PIN_AA1 -to Q[1]
set_location_assignment PIN_W2 -to Q[2]
set_location_assignment PIN_Y3 -to Q[3]

Make sure output.qsf is in the project folder. Finally, add the line source output.qsf to the project's settings file (register.qsf) so that Quartus will use the generated pin assignments. I recommend deleting existing set_location_assignment lines in the project's qsf file to avoid accidental conflicts, then never touching the Pin Planner again.

Command line syntax

$ python pin_gen.py --help
usage: pin_gen.py [-h] [-o OUTPUT] [-s | --strict | --no-strict] [-f | --force | --no-force]
                  in_file

positional arguments:
  in_file               Input file (see below for format notes)

optional arguments:
  -h, --help            show this help message and exit
  -o OUTPUT, --output OUTPUT
                        Output file. Will be clobbered if it exists. If absent, print to
                        stdout or output specified by in_file.
  -s, --strict, --no-strict
                        Escalate warnings to errors
  -f, --force, --no-force
                        Don't ask before overwriting existing files

Input file

The input file is an INI file with two sections, mapping (mandatory) and options (optional). See the configparser docs for more information about the file format.

Pin assignments go in the mapping section as node_name = pin_name. The pin name can be a standard names used in the DE0-CV manual or a direct pin location. Pin names that aren't recognized are skipped with a printed error message.

Any command line flag can alternatively be given in the options section using the long name. If both are used, command line flags take precedence. Boolean options are given as option = True/False and default to False unless otherwise specified.

Buses

Buses, written like abc[start..stop]def, are expanded to a series of individual pin assignments. If the node and pin buses have different sizes, the assignment is skipped with a printed error message.

Start and stop must both be non-negative integers. The range is inclusive; if stop is greater than start then the assignment counts down.

Node buses are expanded with the square brackets (to match Quartus' convention) but pin buses are expanded without the square brackets (to match the DE0-CV pin names). For example, number[0..2] = SW[2..0] will be expanded to:

number[0] = SW2
number[1] = SW1
number[2] = SW0

If expanding a pin bus leads to some valid pins and some invalid pins, the valid pins are kept.