In-depth comparison at STM32 F3 and F4 discovery boards

The STM32 F3 and F4 Discovery boards have been around for a while now. We’ve looked at both separately and they’re impressive dev boards for the price. Now can get a closer look at each from this in-depth comparison of the two Cortex-M4 development tools.

To start off, both of the boards have the same size and footprint (there are two dual-row pin headers which break out the connections to the ARM chip). Fundamentally the F3 and F4 chips have a different level of features, but the boards themselves are aimed at different applications as well. The F3 series of microcontrollers looks to be more affordable than the F4, containing less program memory, no Ethernet capability, and only one USB port. But both have hardware floating-point abilities and they’re blazing fast. The boards offer a MEMS accelerometer for prototyping. But the Discovery-F3 also contains a gyroscope while the Discovery-F4 provides audio hardware like a microphone, and DAC.

If you want to use a Linux box to develop with these tools you might find this guide helpful.

5 thoughts on “In-depth comparison at STM32 F3 and F4 discovery boards

  1. Around for a while? The F3 may have been announced a few months ago, but is only just starting to be available to buy – and still isn’t available in the UK. A nice comparison though.

  2. An important detail that I didn’t see mentioned is the SRAM setup. It’s not just a big block of memory, there’s multiple blocks, some contiguous and some with specific uses. Both have a CCM (Core Coupled Memory) block that is always ready for access with no wait states, but which is not contiguous with the other blocks and can’t be used with DMA, and other blocks that can be accessed by peripherals such as DMA, but which may not be immediately accessible if in use by such a peripheral. A good setup might be to use the CCM for the stack and most program state, and the “system memory” mostly for buffers.

    The F4 has 196 kB of SRAM, not 192 kB: A 64 kB block of CCM SRAM, a 112 kB and a 16 kB block attached to the AHB crossbar switch, each capable of independent access by either the CPU or peripherals, and
    a 4 kB block of battery-backed SRAM (some board hacking required to add a battery), not adjacent to any of the others. The 112 kB and 16 kB blocks are adjacent in the address space and can be treated as a single contiguous 128 kB block.

    The chip on the F3 Discovery board appears to have 8 kB of CCM (on the core’s instruction bus, as opposed to the data bus on the F4 from my understanding of the datasheets) and a 40 kB block on the AHB switch. There’s parity checking on the CCM and the first 16 kB of the system SRAM, which would allow detection of single-bit errors, but not actual error correction.

  3. The L3GD20 has a resonace frequency over 20 khz which is above most of the mechanical vibrations.
    So i guess the F3 Board would be perfect for Quadrokopters.
    St has another gyro the L3GD4200 which has nearly the same pinout but the resonace frequency of this gyro seems to be lower. Making a Quadro with this is also possible but you have to fight more mechanical noise.

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