a.py

#!/usr/bin/env python3.8

import matplotlib.pyplot as plt
import numpy as np
import scipy.optimize as optimization

class T:
    x = 0
    presc = 0
    scldel = 0
    sdadel = 0
    sclh = 0
    scll = 0
    def __init__(self, x, h):
        self.x = x
        self.presc = ((h >> 28) & 0xf) + 1
        self.scldel = ((h >> 20) & 0xf) + 1
        self.sdadel = ((h >> 16) & 0xf)
        self.sclh = ((h >> 8) & 0xff) + 1
        self.scll = ((h) & 0xff) + 1
        assert(self.sdadel == 0)

def load(name):
    r = []
    with open(name, "r") as f:
        for l in f:
            p = l.split()
            x = int(p[0])
            h = int(p[1], 16)
            a = T(x, h)
            r.append(a)
    return r

DATA = [
    load("Desktop/i2c/std-50.txt"),
    load("Desktop/i2c/std-100.txt"),
    load("Desktop/i2c/fast-50.txt"),
    load("Desktop/i2c/fast-100.txt"),
    load("Desktop/i2c/fast-150.txt"),
    load("Desktop/i2c/fast-350.txt"),
    load("Desktop/i2c/fast-400.txt"),
]

print("OK")

A = DATA[-1]
# A = list(filter(lambda a: a.presc == 1, A))

X = [a.x for a in A]
Y = [(a.sclh + a.scll) * a.presc for a in A]
plt.plot(X, Y)

def func(p, x, y):
    v = p[1] * x + p[0]
    return y - v

r = optimization.leastsq(func, np.array([1, 1]), args=(np.array(X), np.array(Y)))
print(r)

Y = [r[0][1] * a.x + r[0][0] for a in A]
plt.plot(X, Y)


# plt.figure()
# Y = [a.scldel * a.presc for a in A]
# plt.plot(X, Y)

# plt.figure()
# Y = [a.scll / a.sclh for a in A]
# plt.plot(X, Y)

plt.show()