Guide to Making an LCM Adapter Board for SiFli Development Boards¶

This document describes how to make a matching adapter board for SiFli development boards to debug third-party displays.

Display Interface Types on SiFli Development Boards¶

16p QSPI FPC
- SF32LB52-DevKit-Nano
- SF32LB52-DevKit-Core
22p QSPI FPC
- SF32LB52-DevKit-LCD
- SF32LB52-DevKit-ULP (LCSC Huangshan Pi)
40p RGB FPC
- SF32LB56-DevKit-LCD
- SF32LB58-DevKit-LCD
30p MIPI-DSI FPC
- SF32LB58-DevKit-LCD

Display Interface Definitions on SiFli Development Boards¶

16p QSPI FPC Interface¶

16p FPC Connector Signal Definition

PIN	DevKit FPC CON PIN-Name	Descriptions	LCM PIN-Name
1	GND	Power Supply Ground	GND
2	LCD_RST	LCD reset output Active low	RESX
3	BL_PWM	Back light PWM control output	BL
4	TE	Tearing effect input	TE
5	QSPI_CS	LCD QSPI Chip select output	CSx
6	QSPI_CLK	LCD QSPI clock output	CLK/WRx
7	QSPI_D0	LCD QSPI data 0 inout	D0/RDx
8	QSPI_D1	LCD QSPI data 1 output	D1/DCx
9	QSPI_D2	LCD QSPI data 2 output	D2
10	QSPI_D3	LCD QSPI data 3 output	D3
11	3.3V	DC 3.3V Power Supply	VCI
22	GND	Power Supply Ground	GND
13	TP_INT	TP Interrupt signal inout	TP-INT
14	TP_SDA	TP I2C data signal	TP-SDA
15	TP_SCL	TP I2C clock signal	TP-SCL
16	TP_RST	TP Reset	TP-RTN

22p QSPI FPC Interface¶

22p FPC Connector Signal Definition

PIN	DevKit FPC CON PIN-Name	Descriptions	LCM PIN-Name
1	LEDK	LED cathode	LEDK
2	LEDA	LED anode	LEDA
3	D2/DB0	LCD QSPI data 2,8080 data 0	DB0
4	D3/DB1	LCD QSPI data 3,8080 data 1	DB1
5	DB2	8080 data 2	DB2
6	DB3	8080 data 3	DB3
7	DB4	8080 data 4	DB4
8	DB5	8080 data 5	DB5
9	DB6	8080 data 6	DB6
10	DB7	8080 data 7	DB7
11	TE	Tearing effect input	TE
12	LCD_RST	LCD reset output Active low	RESX
13	CLK	LCD QSPI clock output	CLK/WRx
14	D0/RD	LCD QSPI data 0 inout	D0/RDx
15	CS	LCD QSPI Chip select output	CSx
16	D1/DC	LCD QSPI data 1 output	D1/DCx
17	3.3V	DC 3.3V Power Supply	VCI
18	TP_INT	TP Interrupt signal inout	TP-INT
19	TP_SDA	TP I2C data signal	TP-SDA
20	TP_SCL	TP I2C clock signal	TP-SCL
21	TP_RST	TP Reset	TP-RTN
22	GND	Power Supply Ground	GND

40p RGB FPC Interface¶

40p FPC Connector Signal Definition

PIN	DevKit FPC CON PIN-Name	Descriptions	LCM PIN-Name
1	5V	DC 5V Power Supply	DC5V
2	5V	DC 5V Power Supply	DC5V
3	R0	Red data 0	DR0
4	R1	Red data 1	DR1
5	R2	Red data 2	DR2
6	R3	Red data 3	DR3
7	R4	Red data 4	DR4
8	R5	Red data 5	DR5
9	R6	Red data 6	DR6
10	R7	Red data 7	DR7
11	GND	Power Supply Ground	GND
12	G0	Green data 0	DG0
13	G1	Green data 1	DG1
14	G2	Green data 2	DG2
15	G3	Green data 3	DG3
16	G4	Green data 4	DG4
17	G5	Green data 5	DG5
18	G6	Green data 6	DG6
19	G7	Green data 7	DG7
20	GND	Power Supply Ground	GND
21	B0	Blue data 0	DB0
22	B1	Blue data 1	DB1
23	B2	Blue data 2	DB2
24	B3	Blue data 3	DB3
25	B4	Blue data 4	DB4
26	B5	Blue data 5	DB5
27	B6	Blue data 6	DB6
28	B7	Blue data 7	DB7
29	GND	Power Supply Ground	GND
30	CLK	clock output	PCLK
31	HSYNC	Horizontal sync signal output	HSD
32	VSYNC	Vertical sync signal output	VSD
33	DE	DE signal when DE mode	DEN
34	BL_PWM	Backlight brightness adjustment signal	BL-PWM
35	TP_RST	TP Reset	TP-RTN
36	TP_SDA	TP I2C data signal	TP-SDA
37	NC	None connect	NC
38	TP_SCL	TP I2C clock signal	TP-SCL
39	TP_INT	TP Interrupt signal inout	TP-INT
40	LCD_RST	LCD reset output Active low	RESX

30p MIPI-DSI FPC Interface¶

30p FPC Connector Signal Definition

PIN	DevKit FPC CON PIN-Name	Descriptions	LCM PIN-Name
1	GND	Power Supply Ground	GND
2	NC	None connect	NC
3	NC	None connect	NC
4	GND	Power Supply Ground	GND
5	D1P	MIPI data Lane 1 positive-end output pin	D1P
6	D1N	MIPI data Lane 1 negative-end output pin	D1N
7	GND	Power Supply Groud	GND
8	DCKP	MIPI clock Lane positive-end output pin	DCKP
9	DCKN	MIPI clock Lane negative-end output pin	DCKN
10	GND	Power Supply Ground	GND
11	D0P	MIPI data Lane 0 positive-end output pin	D0P
12	D0N	MIPI data Lane 0 negative-end output pin	D0N
13	GND	Power Supply Ground	GND
14	NC	None connect	NC
15	NC	None connect	NC
16	GND	Power Supply Ground	GND
17	TE	Tearing effect input	TE
18	LCD_RST	LCD reset output Active low	RESX
19	1.8V	I/O interface power supply,1.8V output	IOVCC
20	3.3V	VCI interface power supply,3.3V output	VCI
21	3.3V	TP power supply,3.3V output	TP-VDD
22	TP_INT	TP Interrupt signal inout	TP-INT
23	TP_SDA	TP I2C data signal	TP-SDA
24	TP_SCL	TP I2C clock signal	TP-SCL
25	TP_RST	TP Reset	TP-RTN
26	LEDK	LED cathode	LEDK
27	LEDK	LED cathode	LEDK
28	NC	None connect	NC
29	LEDA	LED anode	LEDA
30	LEDA	LED anode	LEDA

LCM Adapter Board Signal Connections¶

Multiple series of SiFli development boards use a unified graphical interface to fully support displays with common interface types such as SPI (SPI, DSPI, and QSPI), 8080, 8-bit parallel e-paper, JDI, RGB, and DSI.

SPI, DSPI, and QSPI Interface Displays¶

16p FPC Connector Connected to SPI, DSPI, and QSPI Displays

PIN	DevKit FPC CON PIN-Name	3W-SPI	4W-SPI	DSPI	QSPI
1	GND	GND	GND	GND	GND
2	LCD_RST	RESX	RESX	RESX	RESX
3	BL_PWM	BL	BL	BL	BL
4	TE	NC	NC	NC	TE
5	QSPI_CS	CSx	CSx	CSx	CSx
6	QSPI_CLK	CLK	CLK	CLK	CLK
7	QSPI_D0	RDx	RDx	D0	D0
8	QSPI_D1	NC	DCx	D1	D1
9	QSPI_D2	NC	NC	NC	D2
10	QSPI_D3	NC	NC	NC	D3
11	3.3V	VDD	VDD	VDD	VDD

22p FPC Connector Connected to SPI, DSPI, and QSPI Displays

PIN	DevKit FPC CON PIN-Name	3W-SPI	4W-SPI	DSPI	QSPI
1	LEDK	LEDK	LEDK	LEDK	LEDK
2	LEDA	LEDA	LEDA	LEDA	LEDA
3	D2/DB0	NC	NC	NC	D2
4	D3/DB1	NC	NC	NC	D3
11	TE	NC	NC	NC	TE
12	LCD_RST	RESX	RESX	RESX	RESX
13	CLK	CLK	CLK	CLK	CLK
14	D0/RD	RDx	RDx	D0	D0
15	CS	CSx	CSx	CSx	CSx
16	D1/DC	NC	DCx	D1	D1
17	3.3V	VDD	VDD	VDD	VDD

56LCD Development Board 40p FPC Connector Connected to SPI, DSPI, and QSPI Displays

PIN	56-LCD	3W-SPI	4W-SPI	DSPI	QSPI
1	5V	5V	5V	5V	5V
2	5V	5V	5V	5V	5V
11	GND	GND	GND	GND	GND
15	G3	NC	NC	NC	TE
20	GND	GND	GND	GND	GND
21	B0	CSx	CSx	CSx	CSx
22	B1	CLK	CLK	CLK	CLK
23	B2	RDx	RDx	D0	D0
25	B4	NC	NC	NC	D3
26	B5	NC	DCx	D1	D1
27	B6	NC	NC	NC	D2
29	GND	GND	GND	GND	GND
40	LCD_RST	RESX	RESX	RESX	RESX

58LCD Development Board 40p FPC Connector Connected to SPI, DSPI, and QSPI Displays

PIN	58-LCD	3W-SPI	4W-SPI	DSPI	QSPI
1	5V	5V	5V	5V	5V
2	5V	5V	5V	5V	5V
9	R6	NC	NC	NC	TE
10	R7	CSx	CSx	CSx	CSx
11	GND	GND	GND	GND	GND
12	G0	NC	NC	NC	D3
13	G1	CLK	CLK	CLK	CLK
14	G2	NC	NC	NC	D2
15	G3	NC	DCx	D1	D1
16	G4	RDx	RDx	D0	D0
20	GND	GND	GND	GND	GND
29	GND	GND	GND	GND	GND
40	LCD_RST	RESX	RESX	RESX	RESX

MCU-8080 Interface Display¶

8-bit MCU-8080 is supported only by the 22p and 40p (56-DevKit-LCD) FPC interfaces. The connection methods are shown in the following two tables.

22p FPC Connector Connected to MCU-8080 Displays

PIN	DevKit FPC CON PIN-Name	Descriptions	MCU-8080
1	LEDK	LED cathode	LEDK
2	LEDA	LED anode	LEDA
3	D2/DB0	8080 data 0	DB0
4	D3/DB1	8080 data 1	DB1
5	DB2	8080 data 2	DB2
6	DB3	8080 data 3	DB3
7	DB4	8080 data 4	DB4
8	DB5	8080 data 5	DB5
9	DB6	8080 data 6	DB6
10	DB7	8080 data 7	DB7
11	TE	Tearing effect input	TE
12	LCD_RST	LCD reset output Active low	RESX
13	CLK	Write enable output	WRx
14	D0/RD	Read enable output	RDx
15	CS	Chip select output	CSx
16	D1/DC	Display data/command select output	DCx
17	3.3V	DC 3.3V Power Supply	VCI
18	TP_INT	TP Interrupt signal inout	TP-INT
19	TP_SDA	TP I2C data signal	TP-SDA
20	TP_SCL	TP I2C clock signal	TP-SCL
21	TP_RST	TP Reset	TP-RTN
22	GND	Power Supply Ground	GND

56LCD Development Board 40p FPC Connector Connected to MCU-8080 Displays

PIN	DevKit FPC CON PIN-Name	Descriptions	MCU-8080
1	5V	DC 5V Power Supply	DC5V
2	5V	DC 5V Power Supply	DC5V
11	GND	Power Supply Ground	GND
12	G0	8080 data 2	DB2
13	G1	8080 data 4	DB4
14	G2	8080 data 6	DB6
15	G3	Tearing effect input	TE
16	G4	8080 data 7	DB7
17	G5	8080 data 3	DB3
18	G6	8080 data 5	DB5
20	GND	Power Supply Ground	GND
21	B0	Chip select output	CSx
22	B1	Write enable output	WRx
23	B2	Read enable output	RDx
25	B4	8080 data 1	DB1
26	B5	Display data/command select output	DCx
27	B6	8080 data 0	DB0
29	GND	Power Supply Ground	GND
40	LCD_RST	LCD reset output Active low	RESX

8-bit Parallel E-Paper Display Interface¶

An 8-bit parallel e-paper display requires many I/O interfaces, and the FPC display interface on SiFli development boards cannot meet the I/O count requirement.

For detailed design guidelines, refer to the 8-bit Parallel E-Paper Display Hardware Design Guide.

JDI Parallel Interface Display¶

Common interfaces for JDI displays include a 24p parallel interface and a 10p serial interface. The interface pin sequences are shown in the following two tables.

24p Parallel JDI Signal Definition

PIN	Signal	Descriptions	Connect to
1	LED Cathode 1	Power supply for the LED (Cathode)	Onboard circuit
2	NC	NC	NC
3	VDD2	Power supply for the vertical driver and pixel memory	Onboard circuit
4	JDI_VST	Start signal for the vertical driver	MCU
5	JDI_ENB	Write enable signal for the pixel memory	MCU
6	FRP	Liguid crystal driving signal (“Off” pixel)	MCU
7	VDD1	Power supply for the horizontal driver and pixel memory	Onboard circuit
8	JDI_HST	Start signal for the horizontal driver	MCU
9	JDI_R1	Red image data (odd pixels)	MCU
10	JDI_G1	Green image data (odd pixels)	MCU
11	JDI_B1	Blue image data (odd pixels)	MCU
12	HOUT	Output from the end of the horizontal shift register	MCU
13	VCOM	Common electrode driving signal	MCU
14	JDI_B2	Blue image data (odd pixels)	MCU
15	JDI_G2	Green image data (odd pixels)	MCU
16	JDI_R2	Red image data (odd pixels)	MCU
17	JDI_HCK	Shift clock for the horizontal driver	MCU
18	GND	Ground	GND
19	XFRP	Liguid crystal driving signal (“On” pixel)	MCU
20	JDI_XRST	Reset signal for the horizontal and vertical driver	MCU
21	JDI_VCK	Shift clock for the vertical driver	MCU
22	VOUT	Output from the end of the vertical shift register	MCU
23	LED Anode	Power supply for the LED (Anode)	Onboard circuit
24	LED Cathode 1	Power supply for the LED 2 (Cathode)	Onboard circuit

10p Serial JDI Signal Definition

PIN	Signal	Descriptions	Connect to
1	JDI_SCLK	Serial clock signal	MCU
2	JDI_SI	Serial data input signal	MCU
3	JDI_SCS	Chip select signal	MCU
4	JDI_EXTCOMIN	COM inversion polarity input	MCU
5	JDI_DISP	Display ON/OFF switching signal	MCU
6	VDDA	Power supply for analog	Onboard circuit
7	VDD1	Power supply for logic	Onboard circuit
8	EXTMODE	COM inversion mode select terminal	Onboard circuit
9	VSS	Logic ground	Onboard circuit
10	VSSA	Analog ground	Onboard circuit

For detailed design guidelines, refer to the JDI Display Hardware Design Guide.

RGB (MIPI-DPI) Interface Display¶

Only the SF32LB56-DevKit-LCD and SF32LB56-DevKit-LCD development boards support RGB interface displays. The 40p FPC connector pin sequence on the development board is compatible with the ALIENTEK pin sequence, so an ALIENTEK RGB display can be plugged in directly for use.

Developers can refer to the 40p FPC connector pin sequence defined above and the ALIENTEK RGB display documentation to make a display adapter board.

Third-party RGB display links:

MIPI (MIPI-DSI) Interface Display¶

As shown in the 30p FPC connector signal definitions above, the SiFli SF32LB58-DevKit-LCD development board supports up to 2-lane data transmission and MIPI displays with resolutions up to 1280*800.

For adapter board signal connections, refer to the 30p FPC connector pin sequence above. The development board already integrates a constant-current WLED driver circuit. The backlight LEDK and LEDA can provide 100 mA of drive current, and the display backlight supports up to 6 parallel LED channels. The Rset resistor on the development board can be adjusted according to the specific LED structure of the display to meet the actual drive current requirements.

Important

The I/O level of the development board is 3.3 V. If the I/O level of the driver chip on the LCD adapter board is 1.8 V, use a level-shifter chip to perform level shifting.
The data and clock lines for QSPI, 8080, and RGB need 22–47 ohm resistors connected in series.
The I2C signals on *-Nano and *-Core development boards do not have pull-up resistors, so I2C pull-up resistors need to be added on the display adapter board.

Adapter Board Backlight Circuit¶

TFT Display Backlight Circuit¶

The backlight of a TFT display is generally composed of LED emitters connected in series and parallel. Depending on the display size, the number of series and parallel backlight LEDs also varies. The bare display datasheet usually describes the backlight LED configuration, which should be used to design the backlight driver circuit.

Backlight Composition of Common TFT Screen Sizes

Size	LED Structure	LED VF&IF	LED drive circuit
1.3inch	2 parallel	VF=3.3V,IF=15*2mA	3.3V DC drive
2.4inch	4 parallel	VF=3.3V,IF=15*4mA	3.3V DC drive
2.8inch	4 parallel	VF=3.3V,IF=15*4mA	3.3V DC drive
3.5inch	6 parallel	VF=3.3V,IF=15*6mA	3.3V DC drive
4.2inch	8 serial	VF=25.6V,IF=15mA	Boost WLED driver
5.5inch	2 serial *7 parallel	VF=6.4V,IF=105mA	Boost WLED driver
7inch	3 serial *6 parallel	VF=9.6V,IF=90mA	Boost WLED driver
10.1inch	4 serial *7 parallel	VF=12.8V,IF=105mA	Boost WLED driver

For a backlight driver circuit using a single LED in a parallel configuration, LEDA can be connected directly to the 3.3 V power supply, and LEDK can be connected directly to GND.

For a backlight driver circuit with multiple LEDs connected in series, common 5 V and 3.3 V supplies do not meet the VF voltage requirement, so the LEDs can only be driven by boosting the voltage. It is recommended to use a constant-current LED driver chip to drive the backlight LEDs. The number of parallel LED channels x 15 mA is the current requirement for the display backlight. As shown in the figure below, Rset is used to set the IF drive current. The FB of the chip is generally 200 mV, and IF=VFB/Rset is the drive current.

Common Constant-Current LED Driver Chip Circuit

AMOLED Display Backlight Circuit¶

AMOLED uses pixel-level self-emissive technology and does not have a backlight source like a TFT display. Brightness adjustment is generally performed by adjusting the color of pixels. For example, black means no light emission, and white means maximum brightness. Therefore, no dedicated PWM signal is required to adjust backlight brightness.

AMOLED displays generally include a PMIC chip that provides VGH, VGL, and VCOM voltages to the panel. The display driver chip adjusts the corresponding voltage values through the 1W interface. The PMIC power supply range generally supports 2.7–5.5 V, so 5 V or 3.3 V from the development board FPC connector can be routed to power the PMIC on the display.

Common AMOLED PMIC Chip Circuit

E-Paper Display Backlight Circuit¶

The backlight circuit of an e-paper display is relatively complex and uses a dedicated PMIC chip to provide the voltages for the various power supplies of the e-paper display.

Common PMIC power chips include TPS65185 and SY7637A.

For detailed design guidelines, refer to the 8-bit Parallel E-Paper Display Hardware Design Guide.

FPC Flexible Flat Cable Selection¶

The FPC connector on the SiFli development board is a top-flip, bottom-contact type. When making an adapter board, it is recommended that the FPC connector on the adapter board use a top-flip, dual-contact top-and-bottom type.

Recommended FPC connector:

If a top-flip, dual-contact top-and-bottom FPC connector is used on the adapter board, the FPC flexible flat cable can be a 16p, 22p, 30p, or 40p FPC flexible flat cable with 0.5 mm pitch. The cable contact points can be on the same side or on opposite sides.

Reference FPC Flexible Flat Cable

Important

When designing the adapter board, pay attention to the pin 1 position of the FPC connector. If the adapter board directly references the pin sequence and pin 1 position from the development board schematic, the signals will cross when actually connected with a flexible flat cable and the board cannot be used. The solutions include:

Modify the pin 1 position in the PCB footprint library for the connector on the adapter board, and start numbering the pins from the opposite direction while keeping the schematic symbol unchanged.
Modify the pin 1 position in the schematic symbol library for the connector on the adapter board, and start numbering the pins from the opposite direction while keeping the PCB footprint library unchanged.

SiFli LCM Module¶

To make it easier for developers to use SiFli development boards to debug display functions, SiFli has launched multiple LCM display modules, including QSPI, RGB, and DSI interfaces. The display sizes include a 1.85-inch AMOLED 390x450 watch display, a 4.3-inch TFT 800x480 display, a 7-inch TFT 1024x600 display, and an 8-inch TFT 1280x800 display.

1.85inch AMOLED Module¶

Features¶

Size: 1.85-inch rectangular rounded-corner AMOLED watch display, bare display model: ZC-A1D85W-010
Resolution: 390x450
Brightness: 800 cd/m2
Display data interface: QSPI
Touch data interface: I2C
OLED Driver IC: CO5300AF-01
Power IC: BV6802W
TP IC: FT6146-M00

Development Board Support List¶

SF32LB52-DevKit-Nano
- 16p-0.5mm Pitch-5cm Length-Reverse-FPC
SF32LB52-DevKit-Core-****
- 16p-0.5mm Pitch-5cm Length-Reverse-FPC
SF32LB52-DevKit-ULP (LCSC Huangshan Pi)
- 22p-0.5mm Pitch-5cm Length-Reverse-FPC
SF32LB52-DevKit-LCD
- 22p-0.5mm Pitch-5cm Length-Reverse-FPC
SF32LB56-DevKit-LCD
- 40p-0.5mm Pitch-5cm Length-Reverse-FPC
SF32LB58-DevKit-LCD
- 40p-0.5mm Pitch-5cm Length-Forward-FPC

Development Board and Display Installation Method¶

SF32LB52-DevKit-Nano Development Board Installation Method

SF32LB52-DevKit-Core-**** Development Board Installation Method

SF32LB52-DevKit-ULP (LCSC Huangshan Pi) Development Board Installation Method

SF32LB52-DevKit-LCD Development Board Installation Method

SF32LB56-DevKit-LCD Development Board Installation Method

SF32LB58-DevKit-LCD Development Board Installation Method

Adapter Board Reference Design Materials

4.3inch TFT Module¶

(Coming soon)

7inch TFT Module¶

(Coming soon)

8inch TFT Module¶

(Coming soon)