EXT4 Board Hardware¶

Connector	Description
J1	24 pins connector for connecting with from 1.52” to 3.7” EPD
J2	20-pin header for interfacing with EVK/MCU
J3	Test points for measuring J2 pins

Board Layout¶

EPD Extension Kit Generation 4 (EXT4 Kit) includes a 20-pin cable to quickly interface with any of your chosen development board or current design platform.

The kit has 8 Mbits of Flash memory with an allocated SOIC-8 slot for memory expansion.

Danger

When the EXT4 extension board is connected to the main controller board, ensure only one power source is used.

Either through the USB cable:

Remove the two CR2450 batteries
Power the main controller board and the EXT4 through the USB cable

Or with the two CR2450 batteries:

Disconnect the USB cable, and
Power the main controller board and the EXT4 with the two CR2450 batteries.

Peripherals¶

Programmable LED

WS2813C https://wmsc.lcsc.com/wmsc/upload/file/pdf/v2/lcsc/2304060930_Worldsemi-WS2813C-2020_C5153902.pdf

Accelerometer

LIS2DH12 https://www.st.com/en/mems-and-sensors/lis2dh12.html

Thermometer+Hygrometer

HDC2080 https://www.ti.com/product/HDC2080

Near Field Communication

NT3H2111 https://www.nxp.com/docs/en/data-sheet/NT3H2111_2211.pdf

Pinouts¶

J2 Pin assignment¶

Pin #	Symbol	Description
1	VCC	VCC 3.3V
2	SCK	SPI CLK, serial communication clock input
3	BUSY	Busy state output pin L: EPD driver is busy, data/command is transforming H: host side can send command or data to EPD driver
4	D/C	Serial bus for controlling data or command L: command; H: data
5	RST	Reset signal input
6	MISO	SPI MISO, serial communication data output
7	MOSI	SPI MOSI, serial communication data input
8	FCSM	Master chip select pin of Flash (U1)
9	ECSM	Master chip select pin of EPD
10	GND	Ground
11	Panel_POWER	Soft-reset circuit for EPD
12	Button
13	LED_DATA	Input data pin for LED control
14	I2C_SDA	SDA bus
15	I2C_SCL	SCL bus
16	Flash_CS2	Slave chip select pin of Flash (U2)
17	NFC_Field	Field detection pin for NFC
18	MOTION_INT1	Interrupt pin 1 for accelerometer
19	MOTION_INT2	Interrupt pin 2 for accelerometer
20	TEMP_INT	Interrupt pin for temp/humidity sensor

Power Consumption¶

With all the sensors and peripherals powered, the EXT4 has a mean current draw of 1 mA during standby mode. When driving the EPD, this increases to 4 mA.

For lower power consumption, the added peripherals can be disconnected by desoldering relevant zero-ohm links.

Standby Mode (measurement between points A and B)

Driving the EPD (measurement between points A and B)

Component-level¶

The following table lists the individual low-power/quiescent draw of each peripheral and the relevant resistor for desoldering:

Peripheral	Current Draw	Zero ohm link
LIS2DH12	0.5μA	R10
HDC2080	0.05μA	R13
Flash	0.007μA	R16
WS2813C	0.2mA	R18
NFC	-	R4