The ARM Cortex-M4 core is extremely popular for embedded microcontrollers for good reasons. So what would we need for a perfect implementation? First of all, we need low power, high performance, security, a display controller, and lots of flash. Oh, and it has to be cheap. Your dream has come true.
The STM32F412 and high-temperature STM32F410 are low-cost Cortex-M4-based 84- or 100-MHz microcontrollers with 128 Kbytes to 1 Mbyte of flash and up to 256 Kbytes of RAM. The chip's memory access accelerator implements an instruction pre-fetch queue and branch cache, which increases program execution speed from the flash memory to zero wait states.
Running at 100 MHz with an external clock, PLL ON, and all peripherals disabled, supply current is approximately 15.5 mA from a 1.7-V supply. At 1 MHz, supply current would be only 0.64 mA (PLL off). In stop mode, current is just 18 µA.
The chips have up to four I2 C interfaces, up to four USARTs, USB 2.0 full-speed, and two CAN ports. They do not have an Ethernet port. They have a 16-channel 12-bit A/D converter. The processors come with a high-performance interface to off-chip memory via a dual-mode 100-MHz Quad-SPI port and a flexible memory controller (FMC) for static memory that allows efficient expansion of the integrated flash and RAM. Security features include a true random number generator, a CRC calculation unit, and a 96-bit unique ID.
There is also a parallel LCD interface, which runs displays up to QVGA resolution with 16-bit color depth or WQVGA with 8-bit depth. The ICs come in a WLCSP64 3.658 x 3.686-mm package and is priced from $4.92 ea/1,500.
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