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Updated Expanding 4CH (markdown)

Ion 2018-01-27 14:47:24 +02:00
parent fb81304ec1
commit b7fee56cc0
1 changed files with 4 additions and 4 deletions
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8
Expanding-4CH.md

@ -6,16 +6,16 @@ I ordered on Aliexpress some 2.5 mm jacks and when I received it after some work
<img src="https://github.com/gtortone/Sonoff-Tasmota/blob/development/_temp_imgs/sf4ch-jack.jpg">
</p>
The schematic reports that 2.5 mm jack is configured as following (jack on right side, ESP8255 on the left side:
The schematic reports that 2.5 mm jack is configured as following (jack on right side, ESP8285 on the left side:
<p align="center">
<img src="https://github.com/gtortone/Sonoff-Tasmota/blob/development/_temp_imgs/sf4ch-schematic.png">
</p>
3.3V and GND are very welcome for sensors expansions but GPIO7 and GPIO8 are not usable because they are used internally by ESP8255 for flash memory connection (sigh!)
3.3V and GND are very welcome for sensors expansions but GPIO7 and GPIO8 are not usable because they are used internally by ESP8285 for flash memory connection (sigh!)
R35 and R36 resistors are not soldered on Sonoff 4CH PCB and it is possible to use their pads to "manually route" the jack contact on another ESP2855 pin (!). I selected R35 pad because my "waterproof" DS18B20 sensors provide signal line on TEM1 jack contact.
For ESP8255 pin I prefer IO2 that is already available on header programming pins...
For ESP8285 pin I prefer IO2 that is already available on header programming pins...
Then the route to do is: TEM1 -> R35 pad -> GPIO2:
@ -25,7 +25,7 @@ Then the route to do is: TEM1 -> R35 pad -> GPIO2:
|![](https://github.com/gtortone/Sonoff-Tasmota/blob/development/_temp_imgs/sf4ch-pcb-rear.jpg)|![](https://github.com/gtortone/Sonoff-Tasmota/blob/development/_temp_imgs/rear-zoom.jpg)|
|---|---|
DS18B20 sensors need a 4.7Kohm pullup resistor between DATA pin and 3.3V and this is also useful to pullup GPIO2 in order to avoid ESP8255 reset.
DS18B20 sensors need a 4.7Kohm pullup resistor between DATA pin and 3.3V and this is also useful to pullup GPIO2 in order to avoid ESP8285 reset.
Final result in these photos: