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TheThingsNetworkGateway/Raw-RFM95-Python/rfmtest.py

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# rfmtest.py - performs SPI comms on raspberry pi to RFM95 IC. Paul Richarsd pi@sosgez.co.uk
# NB this is python2 code. SPI data transfer does not use external driver.
#
import RPi.GPIO as GPIO
from time import sleep
# define GPIO board pin assignments for comms
def swait(): # just a short delay.
sleep(0.001)
def initports():
global gclk, gout, gin, ginit, gen
ginit = 15 # wassyn 3 # chip reset
gclk = 23 # CLOCK
gout = 19 # MOSI
gin = 21 # MISO
gen = 24 # chip enable (active low)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(ginit, GPIO.OUT)
GPIO.setup(gclk, GPIO.OUT)
GPIO.setup(gout, GPIO.OUT)
GPIO.setup(gen, GPIO.OUT)
GPIO.setup(gin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
swait()
# set default state
GPIO.output(ginit, 0)
GPIO.output(gclk, 0)
GPIO.output(gout, 0)
GPIO.output(gen, 1)
GPIO.output(ginit, 1)
# READY FOR 1 TRANSFER
def xfr1(iswrite, address, data1):
"""Main SPI data transfer routine. A single byte is transferred out and in."""
global gen, gout, gin, gclk
GPIO.output(gen, 0)
swait()
swait()
d1 = address & 127
if iswrite > 0:
d1 = d1 | 128
swait()
m = 128 # send MSB first
for bit in range(8):
if((d1 & m) > 0):
GPIO.output(gout, 1)
else:
GPIO.output(gout, 0)
swait()
GPIO.output(gclk, 1)
swait()
GPIO.output(gclk, 0)
swait()
m = (m >> 1) & 127
m = 128
d2 = data1
res = 0
for bit in range(8):
if((d2 & m) > 0):
GPIO.output(gout, 1)
else:
GPIO.output(gout, 0)
swait()
res = res << 1
GPIO.output(gclk, 1)
if(GPIO.input(gin) > 0):
res = res | 1
swait()
GPIO.output(gclk, 0)
swait()
m = m >> 1
GPIO.output(gen, 1)
swait()
return res
def writeReg(where, data):
xfr1(1, where, data)
def readReg(where):
return xfr1(0, where, 0)
def ex1(): # just exercising a pin so I can see it on scope
global gclk, gout, gin, gen, ginit
dt = 0.01
port = gen
for x in range(100):
print(1)
GPIO.output(port, 1)
sleep(dt)
print(0)
GPIO.output(port, 0)
sleep(dt)
def readregs():
print("Reg Value")
for x in range(0x44):
# res = -1
v = xfr1(0, x, 0)
print('@', format(x, '02X'))
print(' ', ' $', format(v, '02X'))
def GetOpMode():
# register 1 controls the RFM IC mode. eg FSK/LORA/SLEEP/STANDBY/TX/RX
x = xfr1(0, 1, 0)
return x
def GetRegBitRate():
h = xfr1(0, 2, 0)
l_c = xfr1(0, 3, 0)
return h * 256 + l_c
def GetCarrierFreq():
h = readReg(6) # MSB
m = readReg(7)
l_a = readReg(8) # LSB
return ((h * 256.0 + m) * 256.0 + l_a) * 61.035 # in Hz
def SetFreq(mhz):
f = int(mhz * 1e6 / 61.035)
h = int(f / 65536.0)
r = f - h * 65536
m = int(r / 256)
l_b = r - 256 * m
writeReg(6, h) # MSB
writeReg(7, m)
writeReg(8, l_b) # LSB
return
def GetAGC():
return xfr1(0, 0x61, 0) # or use readReg(0x61) etc
def GetAGC1():
return xfr1(0, 0x62, 0)
def GetAGC2():
return xfr1(0, 0x63, 0)
def GetAGC3():
return xfr1(0, 0x64, 0)
def ShowRegs():
print('Some regsiter examples')
print('Op Mode ', GetOpMode())
print('Bit Rate ', GetRegBitRate())
print('Default carrier freq ', GetCarrierFreq() / 1e6, 'MHz')
print(
'AGC regs 61-64 : ',
format(GetAGC(), '02X'),
format(GetAGC1(), '02X'),
format(GetAGC2(), '02X'),
format(GetAGC3(), '02X')
)
def main():
print('Simple GPIO SPI without drivers')
sleep(0.5) # secs
initports()
readregs() # shows massive list, before any changes are made
ShowRegs() # shows a few interesting registers
SetFreq(868.1) # now write to registers 6, 7, 8
print('New carrier freq ', GetCarrierFreq() / 1e6, ' MHz')
print("*** Finished")
GPIO.cleanup()
main()