Sonoff D1

First Impressions

Seems pretty easy to open up. One philips screw from the front. (Needs a skinny screwdriver tho...)

First thing you see is the important part (From a hacking viewpoint).

There're actually 2 boards with a 4x2 interconnect.

All the power stuff is on the one on the right.

The one on the left is the WiFi & RF board.

Notes

There are 4 chips on the WiFi & RF board:

Label	Part	Notes
U1	Eastsoft ES7P001FGSA GS34BFN404	8-bit MCU?
U2	590R 1933	Probably the RF chip
U3	BB10 F8G A01J1J 1939 A	8-bit MCU
U5	ESP8285

There are 7 test points immediately accessible on the board:

Label	Signal	ESP Pin	Notes
TP3	EXT_RSTB	32	Possibly useful for reset when flashing?
5	GPIO5	24
4	GPIO4	16
0	GPIO0	16
6	GPIO2	14
RX	UORXD	25	Also connected to U3 pin 17 via 0Ω resistor R16
TX	UORXD	26	Also connected to U3 pin 18 via 0Ω resistor R15

This board has 2 4-pin header locations.

J1 seems to connect to U3.

Pin	Label
1	3v3			toward edge
2	C2CK	U3	5
3	C2D	U3	6
4	GND			toward centre

J4 connexts to RX & TX on the ESP chip.

Pin	Label
1	3v3			toward edge
2	E-RX	U5	25
3	E-TX	U5	26
4	GND			toward centre

The interconnect to the power board:

Label	Pin #		Label	Connects to
GND	1		BUZZER	U3 pin 1	toward centre
GND			ZERO_CROSS	U3 pin 20
GND			CONTROL	U3 pin 13
3v3			3v3		toward edge

There are 2 switch locations on the board.

S1 is un-populated but seems to be for a push-button on the ESP chips GPIO0 pin.

S2 is a slide switch labelled "OTA" (Not the default position...). This switch appears to be accessible through a small slot in the front cover of the unit.

Links

Tasmota - Issues - #7598 - Support for Sonoff D1 Dimmer