Search found 26 matches
- Thu Aug 04, 2016 1:24 am
- Forum: ESP8266 boards
- Topic: I/O expander
- Replies: 21
- Views: 22870
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...
- Wed Aug 03, 2016 9:59 am
- Forum: ESP8266 boards
- Topic: I/O expander
- Replies: 21
- Views: 22870
- Tue Aug 02, 2016 3:41 pm
- Forum: ESP8266 boards
- Topic: I/O expander
- Replies: 21
- Views: 22870
Re: I/O expander
Hi mcauser
thank you for the code appreciate .
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?
thank you for the code appreciate .
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?
- Tue Aug 02, 2016 10:34 am
- Forum: ESP8266 boards
- Topic: I/O expander
- Replies: 21
- Views: 22870
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
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
- Mon Aug 01, 2016 4:39 pm
- Forum: ESP8266 boards
- Topic: I/O expander
- Replies: 21
- Views: 22870
Re: I/O expander
Hi pythoncoder
i using firmware micropython 1.8.2,what version you use?
i using firmware micropython 1.8.2,what version you use?
- Fri Jul 29, 2016 7:40 am
- Forum: ESP8266 boards
- Topic: I/O expander
- Replies: 21
- Views: 22870
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...