Bug Report: GLCD SSD1963 component generates [-Woverflow] warnings and fails on PIC32MX795F512L
Posted: Mon Jul 27, 2026 3:30 am
Hello Matrix TSL Team,
I am experiencing a critical issue with the gLCD SSD1963 (Parallel Mode) component in Flowcode 11.2.17 when targeting the PIC32MX795F512L microcontroller on a Mikromedia+ board.
Even with standard properties configurations, the compiler (XC32) outputs three consecutive warnings regarding integer truncation:
"warning: large integer implicitly truncated to unsigned type [-Woverflow]"
The compilation log clearly pinpoints that the truncation overflow happens inside the auto-generated code of the component libraries, specifically inside the following functions:
- FCD_04581_gLCD_SSD1963__Initialise
- FCD_04581_gLCD_SSD1963__ClearDisplay
Because of this math calculation overflow inside the initialisation commands string, the PIC32 execution crashes at boot, blocking the peripheral pins and rendering the display completely unresponsive (including the hardware backlight trigger).
To isolate the issue, I successfully tested other hardware peripherals on the same board. Both the RGB LED pins (RA9, RA14, RA15) and the passive Buzzer (RF13) are working perfectly via Timer 2 interrupts. This confirms that the configuration fuses (80 MHz clock with 16 MHz crystal via PRIPLL, Watchdog disabled, etc.) are 100% correct, and the chip is running normally. The failure is strictly happening during the display component initialization block.
I tried to modify the Display Refresh Rate PLL multipliers/dividers, Colour Bit Depth (switching between 16-bit and 18-bit), and manually selecting colors via the visual picker instead of hex text boxes, but the compiler warnings persist exactly the same.
It seems the internal C/FCDX macro generation code for the PIC32 target is implicitly processing a 32-bit or larger integer where a smaller data type is expected by the component backend structure.
I am attaching the screenshot of the compiler messages. Could you please check if the SSD1963 component C template needs an update or a data type casting fix for the PIC32 toolchain?
Thank you in advance!
Rod
I am experiencing a critical issue with the gLCD SSD1963 (Parallel Mode) component in Flowcode 11.2.17 when targeting the PIC32MX795F512L microcontroller on a Mikromedia+ board.
Even with standard properties configurations, the compiler (XC32) outputs three consecutive warnings regarding integer truncation:
"warning: large integer implicitly truncated to unsigned type [-Woverflow]"
The compilation log clearly pinpoints that the truncation overflow happens inside the auto-generated code of the component libraries, specifically inside the following functions:
- FCD_04581_gLCD_SSD1963__Initialise
- FCD_04581_gLCD_SSD1963__ClearDisplay
Because of this math calculation overflow inside the initialisation commands string, the PIC32 execution crashes at boot, blocking the peripheral pins and rendering the display completely unresponsive (including the hardware backlight trigger).
To isolate the issue, I successfully tested other hardware peripherals on the same board. Both the RGB LED pins (RA9, RA14, RA15) and the passive Buzzer (RF13) are working perfectly via Timer 2 interrupts. This confirms that the configuration fuses (80 MHz clock with 16 MHz crystal via PRIPLL, Watchdog disabled, etc.) are 100% correct, and the chip is running normally. The failure is strictly happening during the display component initialization block.
I tried to modify the Display Refresh Rate PLL multipliers/dividers, Colour Bit Depth (switching between 16-bit and 18-bit), and manually selecting colors via the visual picker instead of hex text boxes, but the compiler warnings persist exactly the same.
It seems the internal C/FCDX macro generation code for the PIC32 target is implicitly processing a 32-bit or larger integer where a smaller data type is expected by the component backend structure.
I am attaching the screenshot of the compiler messages. Could you please check if the SSD1963 component C template needs an update or a data type casting fix for the PIC32 toolchain?
Thank you in advance!
Rod