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9 years, 4 months ago.
Flash overflows with GCC export by adding UART
Hi, I've been using the MBED LPC1768 with the offline GNU toolchain (on Windows) for some time now and recently I switched to compiling for the FRDM-KL05Z.
A basic blinking led is not a problem. However, the second I add a uart port the linker complains about overflowing the flash.
-eabi/4.7.3/../../../../arm-none-eabi/bin/ld.exe: region `FLASH' overflowed by 5344 bytes collect2.exe: error: ld returned 1 exit status
This is by simply calling the exported makefile. The command line this generates is:
arm-none-eabi-g++ -mcpu=cortex-m0plus -mthumb -c -g -fno-common -fmessage-length =0 -Wall -fno-exceptions -ffunction-sections -fdata-sections -fomit-frame-pointe r -MMD -MP -DNDEBUG -Os -DTARGET_KL05Z -DTARGET_M0P -DTARGET_CORTEX_M -DTARGET_F reescale -DTARGET_KLXX -DTOOLCHAIN_GCC_ARM -DTOOLCHAIN_GCC -D__CORTEX_M0PLUS -DA RM_MATH_CM0PLUS -DMBED_BUILD_TIMESTAMP=1418324231.0 -D__MBED__=1 -DTARGET_FF_ARD UINO -std=gnu++98 -fno-rtti -I. -I./external/mbed -I./external/mbed/TARGET_KL05 Z -I./external/mbed/TARGET_KL05Z/TARGET_Freescale -I./external/mbed/TARGET_KL05Z /TARGET_Freescale/TARGET_KLXX -I./external/mbed/TARGET_KL05Z/TARGET_Freescale/TA RGET_KLXX/TARGET_KL05Z -I./external/mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM -o main .o main.cpp
Then the linker generates the error:
arm-none-eabi-gcc -mcpu=cortex-m0plus -mthumb -Wl,--gc-sections --specs=nano.specs -u _printf_float -u _scanf_float -Wl,-Map=frdm_serial.map,--cref -T./external /mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM/MKL05Z4.ld -L./external/mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM -o frdm_serial.elf main.o external/mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM/retarget.o external/mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM/system_MKL05Z4.o external/mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM/board.o external/mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM/cmsis_nvic.o external/mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM/mbed_overrides.o external/mbed/TARGET_KL05Z/TOOLCHAIN_GCC_ARM/startup_MKL05Z4.o -lmbed -lstdc++ -lsupc++ -lm -lc -lgcc -lnosys -lmbed -lstdc++ -lsupc++ -lm -lc -lgcc -lnosys
The code is surprisingly simple...
Serial uart(PTA0, PTA1);
DigitalOut blinky(LED1);
int main()
{
for(;;)
{
wait_ms(100);
blinky = !blinky
}
return 0;
}
Compiling much more complex programs in the online compiler is not an issue. So is this a bug from the GCC toolchain? Or related to my building on Windows?
Any help would be greatly appreciated
Question relating to:
2 Answers
9 years, 4 months ago.
Edit: Yeah, what Martin said :)
Try removing these two options from the linker command line and see what happens:
-u _printf_float -u _scanf_float
That should discard a bunch of floating point code that the UART streaming support pulls in.
I hope that helps,
Adam
Hot diggity! Removing -u _printf_float -u _scanf_float did it.
arm-none-eabi-size Blinky.elf text data bss dec hex filename 16912 136 460 17508 4464 Blinky.elf
I already played with optimizations without any luck.
For future reference the KL05z has 32kB of flash:
Blinky with -u _printf_float -u _scanf_float: arm-none-eabi-size Blinky.elf text data bss dec hex filename 32360 228 608 33196 81ac Blinky.elf Blinky without -u _printf_float -u _scanf_float: arm-none-eabi-size Blinky.elf text data bss dec hex filename 9720 128 352 10200 27d8 Blinky.elf Blinky without -u _printf_float -u _scanf_float with serial: arm-none-eabi-size Blinky.elf text data bss dec hex filename 16912 136 460 17508 4464 Blinky.elf
Still seems high for just a LED and uart though?
posted by 12 Dec 2014
9 years, 4 months ago.
Hi,
you did not specify the size of blinky without uart, the size of KL05Z (not all of us know all flash/ram sizes from top of our heads).
I would start removing floating support specs=nano.specs -u _printf_float -u _scanf_float, and play with optimizations, use LTO?