Cortex-M4 vs. the M3


Last Update: May 23, 2023 @ 18:27 Information subject to change.

This is an Application Note that demonstrates the improved speed of the Cortex-M4 mcu in a second generation IOC board.

Two boards, an IOC-340Z-3 (R&D) with a 72MHz M3 chip, and an IOC-440Z-4 (R&D) with the 168MHz M4 chip are compared. Both boards use the same 800×480 display LCD module.

Both boards have the same USB firmware set to quantify the graphics rendering speed improvements of the M4. A test command sequence was created using PiXCL 20, with both boards running the same test routines sequentially.

Here’s a short video that shows the result.

The graphics test patterns show the speed differential between the M4 and M3 boards. Horizontal lines and rectangular regions draw render at about the same speed. Diagonal lines and circular or polygonal regions require more calculations (for the draw pixel coordinate) by the mcu, which accounts for the speed.

The last comparison screen is the PiXCL demo image with a sun, stars and planet motif, rendered via app code. This screen is also built into the latest firmware as a User Screen. See an example video.

Other Application Notes

Custom USB HID using STM32CubeMX and TrueStudio.

Calibrating the Decaf Real Time Clock.

Interfacing LCD Modules: the LCD_Init problem. 

Interrupt Vector Relocation : Cortex-M3

Timer4 PWM not working: STM32F103VE

Adding an SPI LCD to the IOC-M-2

Adding an SPI 10M Ethernet PHY


 Since you are here, do please have a look around my website.

Decaf IOC-2xe  Decaf IOC-M-2  Decaf IOC-235  Decaf IOC-280Z-4   Decaf IOC-350   Decaf IOC-370 



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