Nextion NX3224T028: Dashboard Template (Gate 107)

This page is a deterministic build sheet for creating a working Nextion HMI in Nextion Editor for the display NX3224T028 (2.8" 320×240 touch).

Target firmware/driver: sensor_nx3224t028_nextion_uart on Gate 107.

0) Assumptions

• Display: NX3224T028 (touch)
• UART baud: 9600
• MCU: RAK3112 UART mapping: TX=GPIO9, RX=GPIO10
• Note: RAK3112 does not expose GPIO15/GPIO16.

1) Project setup (Nextion Editor)

• Create a new project
  • Device: NX3224T028
  • Resolution: 320×240
  • Baud: 9600

Required project settings (don’t skip)

Enable ID reporting so the firmware receives 0x65 touch events:

• Send Component ID: ON
• Return Page ID: ON
• Prefer Release events (not Press) for all buttons

2) Pages

Create exactly two pages:

• page0 — Dashboard (page id 0)
• page1 — Config (page id 1)

Page preinitialize events (required)

Set these in Nextion Editor:

• page0 Preinitialize:

  sendme

• page1 Preinitialize:

  sendme

3) Component map (names + fixed IDs)

page0 (Dashboard)

Name	Type	Component ID	Notes
bStart	Button	2	Start streaming
bStop	Button	3	Stop streaming
bCfg	Button	4	Go to config page
tStat	Text	6	Status text
tLast	Text	7	Last parsed event / last touch
nTx	Number	8	TX counter
nRx	Number	9	RX counter
nPg	Number	10	Current page indicator
tErr	Text	11	Debug/error string (recommended)

page1 (Config)

Name	Type	Component ID	Notes
bHome	Button	5	Return to dashboard

Why fixed IDs? It prevents drift and makes debugging repeatable across project edits.

4) Event behavior map (what each button does)

Use Release event handlers.

page0 events

• bStart (id=2) release → board sets stream RUN
• bStop (id=3) release → board sets stream STOP
• bCfg (id=4) release → board sends page 1

page1 events

• bHome (id=5) release → board sends page 0

Note: The firmware is the source of truth for navigation. The HMI should emit events; the board decides actions.

5) Recommended initial values

Set these once in the editor:

• tStat.txt = "BOOT"
• tLast.txt = "P- C- E-"
• tErr.txt = "" (empty)
• nTx.val = 0
• nRx.val = 0
• nPg.val = 0

6) Build + upload

1. Compile in Nextion Editor.
2. Upload generated .tft:
   • SD card, or
   • serial upload
3. Reboot the display.

7) Firmware run + validation

cd firmware
source ~/esp/esp-idf/export.sh
idf.py -B build_nx3224t028_nextion -p /dev/cu.usbmodem11101 flash monitor

Expected indicators:

• APP_MAIN: active_gate=107
• NX3224: Nextion init ok ... map:start(p0,c2),stop(p0,c3),cfg(p0,c4),home(p1,c5)
• sensor=nx3224t028_nextion ... touch_count:<n> ... last_touch_page:<n> ... last_touch_comp:<n> ...

Troubleshooting:

• If touch_count never increments:
  • project settings likely not emitting 0x65 (Component/Page ID reporting not enabled), or
  • UART wiring/baud mismatch.
• If last_code:0x1A appears repeatedly:
  • dashboard is missing one or more widgets (tStat, tLast, nTx, nRx, nPg, tErr), or
  • component names/IDs don’t match exactly.

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Printable Nextion Editor Checklist (NX3224T028 / Gate 107)

Print this page (browser Print → “Save as PDF”) and use it as a shop-floor checklist.

A) Project

• New project created
• Device set to NX3224T028 (320×240)
• Baud set to 9600
• Settings: Send Component ID = ON
• Settings: Return Page ID = ON

B) Pages

• page0 exists, page id = 0
• page1 exists, page id = 1
• page0 Preinitialize contains sendme
• page1 Preinitialize contains sendme

C) Components + IDs

page0

• bStart Button id=2
• bStop Button id=3
• bCfg Button id=4
• tStat Text id=6
• tLast Text id=7
• nTx Number id=8
• nRx Number id=9
• nPg Number id=10
• tErr Text id=11

page1

• bHome Button id=5

D) Defaults

• tStat.txt = BOOT
• tLast.txt = P- C- E-
• tErr.txt = ""
• nTx.val = 0
• nRx.val = 0
• nPg.val = 0

E) Build + flash

• Compile OK (no editor errors)
• .tft uploaded
• Display rebooted

F) Firmware validation

• Serial log shows active_gate=107
• Touch events increment touch_count
• last_touch_page + last_touch_comp match expectations