Search found 26 matches

by joehunt588
Thu Aug 04, 2016 1:24 am
Forum: ESP8266 boards
Topic: I/O expander
Replies: 21
Views: 9848

Re: RE: Re: I/O expander

@joehunt588 both the SCL and SDA pins on the I2C bus need pull-up resistors (connecting each to VCC). Why? Because when they are missing, the pins are floating (sometimes high, sometimes low). eg. When the master scans the bus for devices, each devices pulls low to respond "hello, I'm here". When t...
by joehunt588
Wed Aug 03, 2016 9:59 am
Forum: ESP8266 boards
Topic: I/O expander
Replies: 21
Views: 9848

Re: I/O expander

Thank you ,now i know[emoji1]
by joehunt588
Tue Aug 02, 2016 3:41 pm
Forum: ESP8266 boards
Topic: I/O expander
Replies: 21
Views: 9848

Re: I/O expander

Hi mcauser

thank you for the code appreciate :D .
may i know where do i need put resistor?do i need to put resistor for SDA and SCL line?Sorry for my noob question do you have schematic where i can follow to put the pull out resistor?
by joehunt588
Tue Aug 02, 2016 10:34 am
Forum: ESP8266 boards
Topic: I/O expander
Replies: 21
Views: 9848

Re: I/O expander

Hi mcauser,

how can i scan i2c port? when i using i2c.scan() it show result in list [4,8 -> 41],by default it 0x20.
can you share me code for PCF8574A python ,i now order the chip :D
by joehunt588
Mon Aug 01, 2016 4:39 pm
Forum: ESP8266 boards
Topic: I/O expander
Replies: 21
Views: 9848

Re: I/O expander

Hi pythoncoder

i using firmware micropython 1.8.2,what version you use?
by joehunt588
Fri Jul 29, 2016 7:40 am
Forum: ESP8266 boards
Topic: I/O expander
Replies: 21
Views: 9848

I/O expander

Hai guy can suggest any working i/o expander for esp8266 that using i2c? im currently struggle using i2c for mcp23017 [code] from machine import Pin, I2C i2c = I2C(scl=Pin(5), sda=Pin(4), freq=100000) #DEVICE = 0x20 # Device address (A0-A2) #IODIRA = 0x00 # Pin direction register #OLATA = 0x14 # Reg...