RISC-V implemented in a night

Depends on what you mean by 'embedded'.

a) Programmable Hardware, like this FPGA, which is outside my wheelhouse. I know it's usually in Verilog, like this project, and usually uses very proprietary toolchains and very expensive chips. But that's about all.

b) Microcontrollers. I'm fairly familiar with AVR chips, which have begun to fall out of favour due to higher power consumption, and rather small memory footprints. Don't optimise, get a ARM M0. C is king here. Or rather, C-style C++, as most toolchains will use a C++ compiler, though most of the C++ library will either be unavailable, or impact performance too much to be justified.

c) Small-scale Linux devices. They still get called embedded, but are far beefier with a much bigger set of concerns, such as security, update routines, and the like.

I fall into microcontroller territory, which is thankfully not so hard to learn.

You can start out small, and learn what you need along the way.

As much as they are ripped on by the community, you can start out with an Arduino - just try not to start out with the Arduino IDE. The not-quite-C++ language they use abstract over most of the things you actually need to know. (A cheap Chinese-clone Arduino can be as little as $2).

The toolchain choice is simple enough, if we're not touching the Arduino IDE:

a) Atmel Studio

b) Any text editor, avr-gcc, avrdude.

A pure-C equivalent to the Arduino 'blink' example, would probably be:

#include <avr/io.h>
#include <util/delay.h>

int main(void) {
  /* Set the register to output */
  DDRB |= _BV(PORTB5);

  while(1) {
    /* Bitshift the register to on */
    PORTB |= _BV(PORTB5);

    _delay_ms(1000);

    /* Bitshift back the other way. */
    PORTB &= ~_BV(PORTB5);

    _delay_ms(1000);
  }

  return 0;
}

Understanding the bitshifts needs two parts:

• Understanding how C works
• Knowing what addresses are defined in the AVR header files

But basically DDRx sets the direction of the pin, input or output.

And PORTx is the group of pins being accessed.

To dive in more, there are a few books like this one that can help, and more to find online too. But, a good grasp of C is where it starts.