BC66 GPIO pins and Dallas Semi temperature sensor

Adrian_Santos · August 11, 2020, 7:31am

Hi @ dopoljak
I didn’t investigate more into the issue. In order to access the GPIO without level converter you would probably need to solder a cable to the modem directly
Please, let me know if make any progress

WizIO · August 11, 2020, 11:15am

clear?

WizIO · August 11, 2020, 3:38pm

enjoy…
(no level-convertor, bypass Olimex pin)

github.com

Wiz-IO/platformio-quectel-examples/blob/master/BC66_SDK/Arduino/BC66_A11_DS1820_DHT_GPIO/src/main.cpp

#include <Arduino.h>

#define DALLAS

#ifdef DALLAS
#include "ds18S20.h"
TSDS18x20 DS18x20;
TSDS18x20 *pDS18x20 = &DS18x20;
/* PINNAME_GPIO1 */
#define DALLAS_A_PIN 9  /* select_arduino_pin */
#define DALLAS_M_PIN 28 /* select_mediatek_pin, see pinsMap[] variant_pins.c */
#else
#include "DHT.h"
DHT_Sensor DHT;
#define DHT_A_PIN /* select_arduino_pin */
#define DHT_M_PIN /* select_mediatek_pin, see pinsMap[] variant_pins.c */
#endif

void setup()
{

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WizIO · August 14, 2020, 1:43pm

Adrian_Santos · August 14, 2020, 2:36pm

To what pin did you connect the sensor VCC? And what value is the resistor?

WizIO · August 14, 2020, 3:03pm

there is 18 free pins, select one…
R = approximately 1 mA for VCC ( I use 3.6k )

dopoljak · August 17, 2020, 7:26am

@WizIO did you manage to connect ultrasonic sensor directly to olimex pin (no need to bypass level convertor ?)

WizIO · August 17, 2020, 8:05am

yep … I use SPI as “counter”
MOSI create the sensor triger
MISO read “bits” … the number of bits are derivatives of the SPI frequency

dopoljak · August 17, 2020, 11:45am

@WizIO gr8 :). is same posible with DHT & DS1820 sensor?

WizIO · August 20, 2020, 7:09am

Ultrasonic HCSR04 over SPI

JarkkoM · September 10, 2020, 7:31pm

Hi, We had a good debugging session today and we were able to solve the Olimex - Dallas sensor noise issue. The issue was in the data line and high frequency noise was blocking the data connection mostly. We found out that there was fan out issue which generated the noise. So, by adding 220 ohm resistor series in both TxD and RxD line solved it. Now we can have 100% good temperature readings by using the posted code above in this thread. Great!

ArturS · November 3, 2020, 2:24pm

@JarkkoM That sounds great, could you share the wiring schematics of the final working setup with Dallas sensor?

JarkkoM · November 10, 2020, 12:00pm

Sure ArthurS, here is circuit for Olimex BC66 board that works for our system. Changes to previous version: Changed first pull up res from 100k to 10k, Added 220R resistors to data lines to avoid ringing.