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SX1276.lua
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SX1276.lua
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--The MIT License (MIT)
--
--Copyright (c) 2016 Jaap Braam
--
--Permission is hereby granted, free of charge, to any person obtaining a copy
--of this software and associated documentation files (the "Software"), to deal
--in the Software without restriction, including without limitation the rights
--to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
--copies of the Software, and to permit persons to whom the Software is
--furnished to do so, subject to the following conditions:
--
--The above copyright notice and this permission notice shall be included in all
--copies or substantial portions of the Software.
--
--THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
--IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
--FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
--AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
--LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
--OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
--SOFTWARE.
--
--Author: Jaap Braam
local now=tmr.now
local gpiowrite=gpio.write
local spisend=spi.send
local spirecv=spi.recv
local bor=bit.bor
local band=bit.band
local bnot=bit.bnot
local delay=tmr.delay
local byte=string.byte
local rtcepoch2cal=rtctime.epoch2cal
local rtcget=rtctime.get
local function padBase64(s)
local p=4-(#s % 4)
return s..string.rep("=",p % 4)
end
local function gmtime(tmst)
local t,us=rtcget()
local diff=now()-tmst
us=us-diff
if us < 0 then
us=us+1000000
t=t-1
end
local tm = rtcepoch2cal(t)
return string.format('%04d-%02d-%02dT%02d:%02d:%02d.%06dZ',tm["year"],tm["mon"],tm["day"],tm["hour"],tm["min"],tm["sec"],us)
end
local MC1={
BW125=0x70,
BW250=0x80,
BW500=0x90,
BW150=0x00
}
MC1["4/5"]=0x02
MC1["4/6"]=0x04
MC1["4/7"]=0x06
MC1["4/8"]=0x08
local MC2={
FSK=0x00,
SF6=0x60,
SF7=0x70,
SF8=0x80,
SF9=0x90,
SF10=0xA0,
SF11=0xB0,
SF12=0xC0
}
local function getName(table,value,mask)
for k,v in pairs(table) do
if bit.band(value,mask) == v then
return k
end
end
return "?"
end
local M={
rxnb=0,
rxok=0,
rxto=0,
txnb=0
}
local _nss=0
local _dio0=1
local _dio1=2
local _freq=868100000
local _sf=MC2.SF7
local _bw=MC1.BW125
local _scanner=function() print("no scanner active") end
local function read(addr)
gpiowrite(_nss, 0)
spisend(1,addr)
local b = spirecv(1,1)
gpiowrite(_nss, 1)
return byte(b)
end
local function readBuffer(addr,len)
gpiowrite(_nss, 0)
spisend(1,addr)
local buf = spirecv(1,len)
gpiowrite(_nss, 1)
return buf
end
local function write(addr,value)
gpiowrite(_nss, 0)
spisend(1,addr+0x80,value)
gpiowrite(_nss, 1)
end
local function pktData()
-- local FIFO_RX_CURRENT_ADDR=0x10
-- local RX_NB_BYTES=0x13
-- local FIFO_ADDR_PTR=0x0D
-- local FIFO=0x00
local curr = read(0x10)
local count = read(0x13)
write(0x0D, curr)
return readBuffer(0x00,count)
end
local tmst=0
local function rxDone()
-- local IRQ_FLAGS=0x12
-- local RxDone=0x40
--local tmst=now()
local pkt={}
pkt.tmst=tmst
pkt.time=gmtime(tmst)
-- clear rxDone
write(0x12, 0x40)
-- message counter
M.rxnb=M.rxnb+1
-- CRC
local irqflags = read(0x12)
if band(irqflags,0x20) == 0x20 then
write(0x12, 0x20)
pkt.stat=-1
else
local rhc = read(0x1C)
if band(rhc,0x40) == 0x40 then
pkt.stat= 1
else
pkt.stat= 0
end
end
if pkt.stat ~= -1 then
local hopch=read(0x1C)
pkt.chan=band(hopch,0x1F) --pktChan()
pkt.rfch=1
pkt.modu="LORA"
local freq=(125000*read(0x08)/2^11)+(125000*read(0x07)/2^3)+(125000*read(0x06)*2^5) --pktFreq() -- in Hz
pkt.freq=string.format("%0d.%03d",freq/1000000,((freq+500)/1000)%1000)
local rssi=read(0x1A)
pkt.rssi=-157+rssi-- pktRssi()
local snr=read(0x19)
if snr > 127 then
snr=-(band(bnot(snr),0xFF)+1)
end
pkt.lsnr=snr/4 --pktLsnr()
local mc1=read(0x1D)
local mc2=read(0x1E)
pkt.datr=getName(MC2,mc2,0xF0)..getName(MC1,mc1,0xF0) -- pktDatr()
pkt.codr=getName(MC1,mc1,0x0E) -- pktCodr()
local data=pktData()
pkt.size=#data
pkt.data=encoder.toBase64(data)
-- message ok counter
M.rxok=M.rxok+1
-- callback
M.rxpk(pkt)
end
end
local function setFreq(freqHz)
-- local FRF_MSB=0x06
-- local FRF_MID=0x07
-- local FRF_LSB=0x08
-- keep resolution for integer version
-- frf = (freqHz*2^19)/32000000
-- frf = (freqHz*2^14)/1000000
-- frf = (freqHz/1000*2^14)/1000
-- frf = (freqHz/1000*2^11)/125
local frf=(freqHz/1000*2^11)/125
local frfMsb=frf/2^16
local frfMid=frf/2^8 % 256
local frfLsb=frf % 256
write(0x06, frfMsb)
write(0x07, frfMid)
write(0x08, frfLsb)
--print(string.format("%0d.%06d Mhz %02X %02X %02X ",freqHz/1000000,freqHz%1000000,frfMsb,frfMid,frfLsb))
end
local function setRate(sf,bw,cr,crc,iiq,powe)
-- local SF10=0xA0
-- local SF11=0xB0
-- local SF12=0xC0
-- local PA_CONFIG=0x09
-- local MODEM_CONFIG1=0x1D
-- local MODEM_CONFIG2=0x1E
-- local MODEM_CONFIG3=0x26
-- local SYMB_TIMEOUT_LSB=0x1F
-- local INVERT_IQ=0x33
local mc1=bor(bw,cr)
local mc2=bor(sf,crc)
--local mc3=0x04
local mc3=0x00 -- no AGC
if (sf == 0xB0 or sf == 0xC0) then mc3=0x08 end -- MC2.SF11=0xB0, MC2.SF12=0xC0
local stl=0x08
if (sf == 0xA0 or sf == 0xB0 or sf == 0xC0) then stl=0x05 end
local pac
if powe > 17 then pac = 0x8F -- 17dbm
elseif powe < -3 then pac = 0x20 -- -3dbm
elseif powe <= 12 then pac = 0x20+powe+3 -- -3dbm .. 12dbm
else pac = 0x80+powe-2 -- 13dbm .. 16dbm
end
write(0x09,pac)
write(0x1D,mc1)
write(0x1E,mc2)
write(0x26,mc3)
write(0x1F,stl)
write(0x33,iiq)
end
local function setChannel(freq,sf)
-- local HOP_PERIOD=0x24
-- local FIFO_ADDR_PTR=0x0D
-- local FIFO_RX_BASE_AD=0x0F
-- local CR4_5=0x02
-- local CRC_ON=0x04
setFreq(freq)
setRate(sf,_bw,0x02,0x04,0x27,14) -- CR4/5=0x02, CRC_ON=0x04
write(0x24,0x00)
write(0x0D,read(0x0F))
end
local function txBuffer(data)
-- local FIFO_ADDR_PTR=0x0D
-- local FIFO_TX_BASE_AD=0x0E
-- local PAYLOAD_LENGTH=0x22
-- local FIFO=0x00
write(0x0D,read(0x0E))
write(0x22,#data)
write(0x00,data)
end
local state=0
local cadSF=0
local function transmitPkt(tmst,freq,sf,bw,cr,crc,iiq,powe,data)
-- local IRQ_FLAGS=0x12
-- local DIO_MAPPING_1=0x40
-- local TxDone=0x08
-- local OPMODE_STDBY=0x01
-- local OPMODE_FSTX=0x02
-- local OPMODE_TX=0x03
local t0=now()
state=3 -- tx
write(0x01,0x80)
write(0x40,0x40) --DIO_MAPPING_1=0x40
gpio.mode(_dio0,gpio.INT)
gpio.trig(_dio0,"up",function()
-- clear TxDone
write(0x12, 0xFF)
--print("TxDone")
_scanner()
end)
setFreq(freq)
setRate(sf,bw,cr,crc,iiq,powe)
txBuffer(data)
write(0x01,0x82)
local t1=now()
local t2=now()
while t2 < tmst do
t2=now()
end
write(0x01,0x83)
M.txnb=M.txnb+1
print("transmitPkt",tmst-t0,tmst-t1,tmst-t2,freq,sf,bw,cr,iiq,powe,#data)
end
local function dio1handler()
-- local IRQ_FLAGS=0x12
-- local DIO_MAPPING_1=0x40
if state == 0 or state == 1 then -- CAD_DETECTED
write(0x01,0x86) -- RX_SINGLE
write(0x12,0xFF) -- clear interrupt flags
state=2
write(0x40,0x03) -- DIO0 RxDone, DIO1 RxTimeout, DIO3 None
delay(256)
local rssi=read(0x1B)
if rssi < 40 then
_scanner()
end
elseif state == 2 then -- RX_TIMEOUT
local rssi=read(0x1B)
print("rx timeout",cadSF/16,"rssi",rssi)
M.rxto=M.rxto+1
_scanner()
end
end
local function dio0handler()
-- local OP_MODE=0x01
-- local IRQ_FLAGS=0x12
-- local MODEM_CONFIG3=0x26
-- local DIO_MAPPING_1=0x40
-- local OPMODE_CAD=0x07
tmst=now()
-- CadDone
if state==1 then
if cadSF < 0xC0 then -- try next SF
cadSF=cadSF+0x10 -- next SF
write(0x1E,cadSF) -- set next SF
if cadSF==0xB4 then
write(0x26,0x0C) -- ModemConfig3: LowDataRateOptimize on
end
if cadSF==0xA4 then
write(0x1F,0x05) -- RegSymbolTimeoutLSB: SymbolTimeout 5
end
write(0x01,0x87) -- set mode LoRa CAD
write(0x12,0xFF) -- clear interrupt flags
delay(256)
local rssi=read(0x1B)
if rssi < 40 then
_scanner()
end
else
_scanner() -- restart scanner
end
elseif state==0 then
write(0x01,0x87) -- set mode LoRa CAD
write(0x12,0xFF) -- clear interrupt flags
delay(256)
local rssi=read(0x1B)
if rssi > 42 then
state=1 -- CAD
else
--hop()
end
elseif state==2 then
local flags=read(0x12)
if band(flags,0x40)==0x40 then
-- RxDone
rxDone() -- handle message received
_scanner() -- restart scanner
end
end
end
local function allSf()
-- local RegOpMode=0x01
-- local OPMODE_SLEEP=0x00
-- local OPMODE_RX=0x05
-- local DIO_MAPPING_1=0x40
write(0x01,0x81) -- set mode LoRa standby
write(0x39,0x34) -- syncword LoRaWan
setChannel(_freq,_sf) -- channel settings in LoRa mode
cadSF=_sf+0x04 -- reset SF hopper
gpio.mode(_dio0,gpio.INT)
gpio.trig(_dio0,"up",dio0handler)
gpio.mode(_dio1,gpio.INT)
gpio.trig(_dio1,"up",dio1handler)
write(0x40,0xA3) -- DIO0 CadDone, DIO1 None, DIO3 None
--start
write(0x01,0x87) -- set mode LoRa CAD
state=0 -- RSSI detect
write(0x12,0xFF) -- clear interrupt flags
delay(256)
local rssi=read(0x1B)
if rssi > 42 then
state=1 -- CAD
end
end
local function singleSf()
write(0x01,0x81) -- set mode LoRa standby
write(0x39,0x34) -- syncword LoRaWan
setChannel(_freq,_sf) -- channel settings in LoRa mode
gpio.mode(_dio0,gpio.INT)
gpio.trig(_dio0,"up",function()
tmst=now()
rxDone()
write(0x12,0xFF) -- clear interrupt flags
end)
write(0x40,0x03) -- DIO0 RxDone, DIO1 RxTimeout, DIO3 None
write(0x01,0x85) -- set mode LoRa rxContinuous
end
function M.rxpk(pkg)
print(cjson.encode(pkg))
end
local txTimer=tmr.create()
function M.txpk(pkt)
--{"txpk":{"codr":"4/5","data":"YHBhYUoAAwABHOZxE2w","freq":869.525,"ipol":true,"modu":"LORA","powe":27,"rfch":0,"size":14,"tmst":190582123,"datr":"SF9BW125"}}
local tmst=pkt.tmst+1000 -- Send a bit later than commanded by the txpk. Works much better for OTAA, I don't know why...
local freq=pkt.freq
local sf=MC2[pkt.datr:sub(1,-6)]
local bw=MC1[pkt.datr:sub(-5)]
local cr=MC1[pkt.codr]
local crc=0x00 -- crc disabled...
local iiq=0x27
if pkt.ipol==true then iiq=0x40 end
local powe=pkt.powe
local size=pkt.size
local data=encoder.fromBase64(padBase64(pkt.data)):sub(1,size)
-- trigger transmitPkt 30ms before the message has to be sent.
-- a large margin is necessary because the ESP's timing is 'not so precise'
local trig=((tmst-now())/1000)-30
if trig > 0 then
txTimer:alarm(trig,tmr.ALARM_SINGLE,function() transmitPkt(tmst,freq,sf,bw,cr,crc,iiq,powe,data,size) end)
else
transmitPkt(tmst,freq,sf,bw,cr,crc,iiq,powe,data,size)
end
local msg='{"txpk_ack":{"error":"NONE"}}'
if trig <= 0 then
msg='{"txpk_ack":{"error":"TOO_LATE"}}'
end
return msg
end
local function sxInit()
-- local VERSION=0x42
-- local OPMODE_SLEEP=0x00
-- local SYNC_WORD=0x39
-- local LNA=0x0C
-- local MAX_PAYLOAD_LENGTH=0x23
-- local PAYLOAD_LENGTH=0x22
-- local PREAMBLE_LSB=0x21
-- local PA_RAMP=0x0A
-- local PA_DAC=0x5A
-- local LNA_MAX_GAIN=0x23
local version = read(0x42)
if (version ~= 0x12) then
print("Unknown radio: ",version)
end
write(0x01,0x80)
write(0x39,0x34)
write(0x0C,0x23)
write(0x22,0x40)
write(0x21,0x08)
write(0x0A, bor(band(read(0x0A),0xF0),0x08)) --set PA ramp-up time 50 uSec
write(0x5A,bor(read(0x5A),0x04))
write(0x37,0x0A) -- detection threshold
end
local function init(nss,dio0,dio1,freq,sf,bw)
--
node.setcpufreq(node.CPU160MHZ)
-- setup SPI
spi.setup(1,spi.MASTER,spi.CPOL_LOW,spi.CPHA_LOW,spi.DATABITS_8,3)
_nss=nss
gpio.mode(_nss, gpio.OUTPUT)
-- init radio
sxInit()
-- setup handlers
_dio0=dio0
_dio1=dio1
_freq=freq
_bw=MC1[bw]
if (sf=="ALL") then
_sf=MC2["SF7"]
_scanner=allSf
print("start allSF detector")
else
_sf=MC2[sf]
_scanner=singleSf
print("start singleSF detector on",sf)
end
_scanner()
return M
end
return init