sebascarra
commented
5 years ago Alright, I have found some more information. First of all, in the "asInterface" example the LED was set to pin 8 (not 13 as I would have expected for a Uno/Nano) and the 1-Wire pin was set to D1. Looking at the datasheet, D1 has a 1k resistor in series with the pin, so there wasn't a chance it was going to work (today I've changed the pulldown from 5k to 1k, so that disabled me from properly pulling down the bus.
The behavior is now better, but I have to tell you guys that the LED keeps blinking rapidly. Basically LED13 is powered on upon reset, and what's going on is that at some point the Arduinos "crash" and get stuck on a reset loop.
Any ideas? I've read something about some bug with the watchdog timer.
Thanks & Regards
thomasesr
Hello, I have the following setup:
(*)Code on master Arduino:
`
include
/ DS18S20 Temperature chip i/o /
OneWire ds(10); // on pin 10
void setup(void) { Serial.begin(19200); }
void loop(void) { byte i; byte present = 0; byte data[12]; byte addr[8];
if ( !ds.search(addr)) { Serial.print("No more addresses.\n"); ds.reset_search(); delay(250); return; }
Serial.print("R="); for( i = 0; i < 8; i++) { Serial.print(addr[i], HEX); Serial.print(" "); }
if ( OneWire::crc8( addr, 7) != addr[7]) { Serial.print("CRC is not valid!\n"); return; }
if ( addr[0] != 0x28) { Serial.print("Device is not a DS18S20 family device.\n"); return; }
// The DallasTemperature library can do all this work for you!
ds.reset(); ds.select(addr); ds.write(0x44,1); // start conversion, with parasite power on at the end
delay(1000); // maybe 750ms is enough, maybe not // we might do a ds.depower() here, but the reset will take care of it.
present = ds.reset(); ds.select(addr);
ds.write(0xBE); // Read Scratchpad
Serial.print("P="); Serial.print(present,HEX); Serial.print(" "); for ( i = 0; i < 9; i++) { // we need 9 bytes data[i] = ds.read(); Serial.print(data[i], HEX); Serial.print(" "); } Serial.print(" CRC="); Serial.print( OneWire::crc8( data, 8), HEX); Serial.println(); } `
This setup works for a while. TX blinks about once every second or so, both on the master Arduino as on the slaves. The serial monitor reports 22 devices (7 Nano 1 + 7 Nano 2 + 7 Nano 3 + real sensor). Eventually, after 1 minute or so, one of the slave Arduinos fail. The pin 13 LED blinks fast, and its associated slaves fail to appear on the serial monitor). Eventually, all slaves fail, it's kind of random but I can say one fails every 1-2 minutes. This is all set up on a protoboard just in case you ask.
What I actually want to do is:
I need to create a multidrop network with 1 slave (an Arduino Nano running this library) simulating 1 sensor, one slave every 50 cm along a Cat5e cable, for 100 m. That's 200 simulated slaves.
I have a crappy USB oscilloscope (Hantek 6022BE) I might be able to use to debug, but do you think I will be able to run 200 slaves using this? I don't need real 1-Wire support, I'm only using emulated devices, so I can just duplicate/quadruple all times to lower the protocol's frequency by 2 or 4 times (modifying both the master and the slave). I can still use a much lower speed. Do you think that would work better?
Thank you & regards.