From ea562735e2dabc5c22d84a78caff9f9e994819c6 Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Sun, 31 Mar 2019 06:20:52 +0000
Subject: [PATCH] - make class of it

git-svn-id: http://moon:8086/svn/projects/HendiControl@189 fda53097-d464-4ada-af97-ba876c37ca34
---
 Control/brewpi/max31865.py | 142 ++++++++++++++++++++-----------------
 1 file changed, 77 insertions(+), 65 deletions(-)

diff --git a/Control/brewpi/max31865.py b/Control/brewpi/max31865.py
index b68d011..4f4554e 100755
--- a/Control/brewpi/max31865.py
+++ b/Control/brewpi/max31865.py
@@ -1,89 +1,101 @@
 #!/usr/bin/python
 
 import spidev
-import time
-import os
- 
-# Open SPI bus
-spi = spidev.SpiDev()
-spi.open(0,0)
-spi.max_speed_hz=100000
-spi.mode = 0b01
 
-def read_reg(addr):
-	reg = spi.xfer([addr, 0xFF]);
 
-	return reg[1]
-	
-def write_reg(addr, data):
-	spi.xfer([addr+0x80, data]);
+class Max31865():
+	def __init__(self):
+		# Open SPI bus
+		self.spi = spidev.SpiDev()
+		self.spi.open(0, 0)
+		self.spi.max_speed_hz = 100000
+		self.spi.mode = 0b01
+		self.write_reg(0x00, 0xA3)
 
-def read_digits():
-	msb = read_reg(0x01)
-	lsb = read_reg(0x02)
-	digits = float(256*msb + lsb)/2
+	def read_reg(self, addr):
+		reg = self.spi.xfer([addr, 0xFF])
 
-	return digits
+		return reg[1]
 
-def calc_R(Rref, digits):
-	k = digits / 8192 / 4
-	R = k*Rref
+	def write_reg(self, addr, data):
+		self.spi.xfer([addr+0x80, data])
 
-	return R
+	def read_digits(self):
+		msb = self.read_reg(0x01)
+		lsb = self.read_reg(0x02)
+		digits = float(256*msb + lsb)/2
 
-def vanDusenLut (R0, Tmin, Tmax, dT):
-	a = +3.90830e-03;
-	b = -5.77500e-07;
-	c = -4.18301e-12;
+		return digits
 
-	Rv = []
-	Tv = []
-	T = Tmin
-	while T <= Tmax:
-		R = R0*(1 + a*T + b*T**2)
+	def getTemperature(self):
+		digits = self.read_digits()
+		R = max31865.calc_R(430, digits)
+		T = max31865.vanDusen_temp(R)
+		print("R={:.3f} Ohm, T={:.2f} degC".format(R, T))
+		return T
 
-		if T < 0.0:
-			R += R0*c*(T - 100)*T**3;
-		
-		Rv.append(R)
-		Tv.append(T)
-		T += dT
+	@staticmethod
+	def calc_R(Rref, digits):
+		k = digits / 8192 / 4
+		R = k*Rref
 
-	return Rv, Tv
+		return R
 
-def vanDusen_temp(Rmeas):
-	RLut, TLut = vanDusenLut(100, -150, +500, 1.0)
+	@staticmethod
+	def vanDusenLut (R0, Tmin, Tmax, dT):
+		a = +3.90830e-03
+		b = -5.77500e-07
+		c = -4.18301e-12
 
-	# Find candidate
-	i = 0
-	for R in RLut:
-		if R > Rmeas:
-			break
-		i += 1
+		Rv = []
+		Tv = []
+		T = Tmin
+		while T <= Tmax:
+			R = R0*(1 + a*T + b*T**2)
 
-	# Linear interpolation
-	R0 = RLut[i-1]
-	R1 = RLut[i]
-	T0 = TLut[i-1]
-	T1 = TLut[i]
+			if T < 0.0:
+				R += R0*c*(T - 100)*T**3
 
-	dR = R1 - R0
-	dT = T1 - T0
+			Rv.append(R)
+			Tv.append(T)
+			T += dT
 
-	k = (Rmeas-R0)/dR
-	T = T0 + dT*k
+		return Rv, Tv
+
+	@staticmethod
+	def vanDusen_temp(Rmeas):
+		RLut, TLut = Max31865.vanDusenLut(100, -150, +500, 1.0)
+
+		# Find candidate
+		i = 0
+		for R in RLut:
+			if R > Rmeas:
+				break
+			i += 1
+
+		# Linear interpolation
+		R0 = RLut[i-1]
+		R1 = RLut[i]
+		T0 = TLut[i-1]
+		T1 = TLut[i]
+
+		dR = R1 - R0
+		dT = T1 - T0
+
+		k = (Rmeas-R0)/dR
+		T = T0 + dT*k
+
+		return T
 
-	return T
 
 # Main
-write_reg(0x00, 0xA3)
-digits = read_digits()
-R = calc_R(430, digits)
-T = vanDusen_temp(R)
-print("R={:.3f} Ohm, T={:.2f} degC".format(R, T))
+if __name__ == '__main__':
 
-for i in range (0, 8):
-	print("Reg[0x{}]: 0x{:02X}".format(i, read_reg(i)))
+	max31865 = Max31865()
+	for i in range (0, 8):
+		print("Reg[0x{}]: 0x{:02X}".format(i, max31865.read_reg(i)))
 
-print("End of program")
+	max31865.getTemperature()
+
+	print("End of program")