Search found 8 matches

by SirN Check
Sun Jul 05, 2020 1:35 am
Forum: ESP32 boards
Topic: RMT pin state
Replies: 7
Views: 377

Re: RMT pin state

Well, I don't know if I am that qualified. But I got it going , using the same trick I use to get SPI working after the reset button been pressed: import esp32 from machine import Pin r = esp32.RMT(0, pin=Pin(18), clock_div=8, carrier_freq=38000, carrier_duty_percent=30) r.deinit() # Needed, else RM...
by SirN Check
Sat Jul 04, 2020 2:11 am
Forum: ESP32 boards
Topic: RMT pin state
Replies: 7
Views: 377

Re: RMT pin state

Correct me if I'm wrong! With a ESP32-WROVER-B and e.g. esp32spiram-idf3-20200703-unstable-v1.12-614-gc2317a3a8.bin: The RMT example(s) in the Doc's does not work as the r.write_pulses((1, 20, 2, 40), start=0) never terminates. ( r.wait_done() = False ) With esp32-idf3-20191220-v1.12.bin it works. B...
by SirN Check
Sat Jun 13, 2020 8:31 pm
Forum: MicroPython pyboard
Topic: some troubles with the DS18B20-PAR temperature sensor
Replies: 4
Views: 1224

Re: some troubles with the DS18B20-PAR temperature sensor

First PAR-buzz didn't last very long. The patch, using "viper" to turn on strong pullup , stopped working when const was replaced by variables in the onewire.py Sorry. Thus, this proposal is to add the strong pullup before the _CONVERT byte is written. The following class modifications work, alas no...
by SirN Check
Fri Jun 05, 2020 11:45 pm
Forum: ESP32 boards
Topic: DS18B20 wrong serial code/adress/roms
Replies: 5
Views: 795

Re: DS18B20 wrong serial code/adress/roms

Don't forget to also pick up some pull-up resistors!
Internal pull-up are much too weak.
At 3v3: 1k5, 1k8 or 2k2 will do the trick.
Especially when using long cables & multiple sensors!
by SirN Check
Wed Apr 01, 2020 1:18 pm
Forum: ESP32 boards
Topic: DS18B20 readings are wrong
Replies: 10
Views: 678

Re: DS18B20 readings are wrong

Try the stronger pullup suggestion! !!!
Especially with long cables.
1k5 @3v3 => 2mA = OK

This is true for both modes!
by SirN Check
Thu Mar 26, 2020 9:06 pm
Forum: MicroPython pyboard
Topic: some troubles with the DS18B20-PAR temperature sensor
Replies: 4
Views: 1224

Re: some troubles with the DS18B20-PAR temperature sensor

Reading DS18B20-PAR temperature (with ESP32) This is how I got eight DS18B20’s, in PAR-mode, running using one I/O pin. (each on a 3m cable.) Well, probably GXCAS 18B20, according to https://github.com/cpetrich/counterfeit_DS18B20 What really compelled me to use parasitic mode was the fact that som...
by SirN Check
Thu Oct 24, 2019 12:12 pm
Forum: ESP32 boards
Topic: CRC err DS18B20 OneWire ESP32
Replies: 2
Views: 565

CRC err DS18B20 OneWire ESP32

Anyone else getting CRC errors using latest version: esp32spiram-20191023-v1.11-497-gf301170c7.bin ?
Versions <= 'v1.11-481-' works fine!

#I always use protection during transfer:
state = machine.disable_irq()
# talk onewire
machine.enable_irq(state)
by SirN Check
Fri Dec 15, 2017 12:27 pm
Forum: WiPy and CC3200 boards
Topic: Onewire and DS18B20
Replies: 42
Views: 28875

Re: Onewire and DS18B20

Hello, While the DS18x20 is "measuring" it draws extra power. ~1.5mA Thus the "-par" version needs temporarily a much stronger pull-up. Using a non-par version eliminates this problem. But as the "-par" is quite nice: I would like to see software support using an extra pin for the "strong pull-up" A...