Build system reference

libfx2 provides a flexible build system based on GNU Make for convenient development. It provides:

  • out-of-tree builds,

  • rebuilds after changes to application headers,

  • rebuilds (of both libfx2 and application) after changes to libfx2,

  • minimal and readable configuration for most common cases,

  • a load target for building and uploading the design using fx2tool.

To start using it, create a source file…

main.c
#include <fx2regs.h>

int main(void) {
  IOA = OEA = 1;
  while(1);
}

... and a Makefile, replacing .../libfx2 with the path to the root of this repository…

Makefile
LIBFX2 = .../libfx2/firmware/library
include $(LIBFX2)/fx2rules.mk

... and you’re done! Running make will build a firmware.ihex, and running make load will run it on any connected Cypress development kit.

Of course, as your project grows, so has your build system. The configuration values that may be set are as follows:

  • TARGET sets the base name of the output Intel HEX file. It is firmware if not specified.

  • SOURCES lists the .c or .asm source files to be built, without extension. It is main if not specified.

  • LIBRARIES lists the standard libraries to be linked in, without extension. It is fx2isrs by default, and can be any of fx2, fx2isrs and fx2usb.

  • VID, PID set the USB VID:PID pair used to search for the development board. They are 04B4:8613 if not specified, which is the VID:PID pair of the Cypress development kit.

  • MODEL sets the sdcc code model, one of small, medium, large or huge. The libfx2 standard library as well as sdcc standard library are built for all code models. It is small if not specified.

  • CODE_SIZE, XRAM_SIZE set the sizes of the corresponding sdcc segments. The CODE and XRAM segments must add up to at most 0x4000. They are 0x3e00 and 0x0200 if not specified.

  • CFLAGS appends arbitrary flags to every sdcc invocation.

An elaborate Makefile could look as follows:

Makefile
VID      ?= 20b7
PID      ?= 9db1

TARGET    = glasgow
SOURCES   = main leds fpga dac_ldo adc
LIBRARIES = fx2 fx2usb fx2isrs
MODEL     = medium
CODE_SIZE = 0x3000
XRAM_SIZE = 0x1000
CFLAGS    = -DSYNCDELAYLEN=16

LIBFX2    = ../vendor/libfx2/firmware/library
include $(LIBFX2)/fx2rules.mk