francisrstokes

# X_k = \sum_{n=0}^{N-1} x_n \cdot e^{-\frac{j 2 \pi k n}{N}}
# X_k = \sum_{n=0}^{N-1} x_n \cdot [\cos(-\frac{2 \pi k n}{N}) + j\sin(-\frac{2 \pi k n}{N})]

import math
import cmath

def generate_data(timespan=64):
    data = []
    for i in range(timespan):
        ni = i/timespan

francisrstokes

import re
import sys
import subprocess

callgrind_file = sys.argv[1]
executable_file = sys.argv[2]

if len(sys.argv) < 3:
    print("Usage: fix-callgrind.py <callgrind file> <executable>")
    sys.exit(1)

francisrstokes

#include "machine.h"

void state_machine_step(state_machine_t* descriptor) {
  state_transition_t* transition;
  uint32_t current_state = *descriptor->state_index;

  for (uint32_t i = 0; i < descriptor->num_transitions; i++) {
    transition = &descriptor->transitions[i];
    if ((transition->from_state == current_state) && (transition->condition(current_state))) {
      descriptor->on_state_change(current_state, transition->to_state);

francisrstokes

 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
+------------------------------------------------------------------------------------------------+
| funct7             | rs2          | rs1          | funct3 | rd           | opcode              | R-type
| imm[11:0]                         | rs1          | funct3 | rd           | opcode              | I-type
| imm[11:5]          | rs2          | rs1          | funct3 | imm[4:0]     | opcode              | S-type
| imm[12|10:5]       | rs2          | rs1          | funct3 | imm[4:1|11]  | opcode              | B-type
| imm[31:12]                                                | rd           | opcode              | U-type
| imm[20|10:1|11|19:12]                                     | rd           | opcode              | J-type
+------------------------------------------------------------------------------------------------+

francisrstokes

             Pinout for Nucleo-F401RE
 _________________________________________________
|     O                                           |
|                   User    Reset                 |
|                   [B]     [B]                   |
|   PC10    PC11                    PC9   PC8     |
|   PC12    PD2                     PB8   PC6     |
|   VDD     E5V                     PB9   PC5     |
|   BOOT0   GND                     AVDD  U5V     |
|   NC      NC                      GND   NC      |

francisrstokes

uint16_t BitReverse16(uint16_t value) {
  value = (value & 0xFF00) >> 8 | (value & 0x00FF) << 8;
  value = (value & 0xF0F0) >> 4 | (value & 0x0F0F) << 4;
  value = (value & 0xCCCC) >> 2 | (value & 0x3333) << 2;
  value = (value & 0xAAAA) >> 1 | (value & 0x5555) << 1;

  return value;
}

francisrstokes

#!/usr/bin/env python

import math
import subprocess
from random import choice
from argparse import ArgumentParser

def random_filename():
    letters = [chr(ord("a") + x) for x in range(26)]
    return "".join([choice(letters) for _ in range(12)])

francisrstokes

NAME          := firmware

# Utility commands
RM            := rm -rf
DIR_DUP       = mkdir -p $(@D)

# Compiler commands
GCC_PREFIX    := arm-none-eabi
CC            := $(GCC_PREFIX)-gcc
OBJCOPY       := $(GCC_PREFIX)-objcopy

francisrstokes

#!/bin/bash

# Run this script as root on a linux machine to
# block (at least some) facebook trackers

echo "0.0.0.0   www.facebook.com" >> /etc/hosts
echo "0.0.0.0   facebook.com" >> /etc/hosts
echo "0.0.0.0   login.facebook.com" >> /etc/hosts
echo "0.0.0.0   www.login.facebook.com" >> /etc/hosts
echo "0.0.0.0   fbcdn.net" >> /etc/hosts

francisrstokes

{
  "title": "Map CapsLock plus i/j/k/l to Arrows",
  "rules": [
    {
      "description": "Map CapsLock plus i/j/k/l to Arrows",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "j",