The 2.0 inch board

What it is for

240 × 320 pixels is 76,800 of them: 153,600 bytes a frame, which at the library's 40 MHz clock is at least 30.7 ms on the wire. Controller in the library's table: ST7789. The panel's own sheet does not name one.

The lit area is 30.6 × 40.8 mm, which makes the pixel 0.1275 mm: the smallest of the six, about 200 to the inch. It suits a small dashboard where the text should look printed rather than drawn.

Outline and holes

The board is 36.0 mm across and 64.0 mm tall, 1.6 mm thick, with four 4.8 mm holes 24.0 mm apart across and 56.0 mm down, 6.0 mm in from the sides and 4.0 mm from the top and bottom. The header holes are 2.54 mm apart and 17.78 mm across, centred on the top edge, pin 1 (GND) the square one at the left.

The glass module is 34.6 × 47.8 mm on the back; the tail comes through a slot 10.2 mm wide and 6 mm tall.

The socket the panel plugs into

The ribbon goes into FPC1, a 14-way, 0.5 mm socket (KH-CL0.5-H2.0-14PIN-SMT). Its pin 1 is at the right-hand end with the header at the top, and the silkscreen numbers it 14 to 1 from the left. What the board wires to each pin:

The panel's own sheet lists the same fourteen in the same order, so this socket and that tail can be read side by side: its pin 4 is the lamp's anode, 10 is the logic supply and 11 the I/O supply, and the board puts all three on 3V3. Three grounds, three 3V3 and a lamp pin leave five signals, and those are the five the header carries.

The backlight

Q2, a BSS138 N-channel transistor, sits on the low side of the lamp: its gate is the BL pad with R2 (10 kΩ) from gate to GND, its drain goes through R6 (2.2 Ω) to socket pin 3, and the lamp's high side is on 3V3. BL HIGH is lit; a BL pad nothing drives is dark.

Its two jumpers

Both are open as shipped.

• CS, silkscreen GND CS, at the left, level with the socket: bridged, CS is tied to GND and the display is always selected. Do not then drive the CS pad.
• SB3, silkscreen 3V3 BL, at the right, above the socket: bridged, BL is tied to 3V3 and the lamp is lit whenever there is power. Leave the BL pad unconnected.

Both are covered in the two solder jumpers.

Wiring and the constant

// 3V3 -> 3V3        GND -> GND
// SCL -> GPIO 12    MOSI -> GPIO 11      (classic ESP32: 18, 23)
// DC  -> GPIO 2     RST  -> GPIO 42      (classic ESP32: 2, 4)
// CS  -> GPIO 10    BL   -> GPIO 41      (classic ESP32: 15, 32)
LB_Display display(LB_TFT_20);

#include <LonelyBinaryDisplay.h>
LB_Display display(LB_TFT_20);    // the only line that changes per panel

from lb_display import LBDisplay
from lb_panels import TFT_20       # the only line that changes per panel
d = LBDisplay(TFT_20)

3.3 V only. Wiring for your board has the pins for other chips.

What is different about this one

Not much, and that is the point. The 2.0, 2.4 and 2.8 inch are one 240 × 320 picture on three sizes of glass; this is the smallest of the three, so it is the sharpest, and a sketch moves between them by one constant.

On the board itself, the things to know are the 14 contacts (the most of the six), the two unused ones at the ends, and that its header row is holes in the model, with no pins drawn. Next, first light runs the self-test.