Add OLED display support for Heltec WiFi LoRa 32 V3#1
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- Automatically initialize GPIO36 and pull LOW on startup - Enables OLED power supply (Vext) without manual wiring - Checks for HELTEC_VEXT_PIN build flag before initialization - Supports WLED 17.1.1 release with integrated display support https://claude.ai/code/session_0177tCiDXsjQyQ86Nu7VYP5S
WalkthroughThe four-line display usermod's setup method now conditionally initializes the HELTEC_VEXT_PIN GPIO when defined, configuring it as an output and driving it low. ChangesHELTEC VEXT GPIO Setup
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🧹 Nitpick comments (2)
usermods/usermod_v2_four_line_display_ALT/usermod_v2_four_line_display_ALT.cpp (2)
218-221: 💤 Low valueConsider disabling Vext if display initialization fails.
If display allocation or initialization fails (lines 253-260), the Vext pin remains powered LOW. For better power management and cleanliness, consider turning off Vext when the display is set to
NONE.♻️ Suggested enhancement for power management
In the failure path around line 259, add:
if (nullptr == u8x8) { DEBUG_PRINTLN(F("Display init failed.")); if (isSPI) { PinManager::deallocateMultiplePins((const uint8_t*)ioPin, 3, PinOwner::UM_FourLineDisplay); } +#ifdef HELTEC_VEXT_PIN + digitalWrite(HELTEC_VEXT_PIN, HIGH); // Disable Vext power + PinManager::deallocatePin(HELTEC_VEXT_PIN, PinOwner::UM_FourLineDisplay); +#endif type = NONE; return; }🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@usermods/usermod_v2_four_line_display_ALT/usermod_v2_four_line_display_ALT.cpp` around lines 218 - 221, Display power (HELTEC_VEXT_PIN) is left enabled (digitalWrite(HELTEC_VEXT_PIN, LOW)) even when display allocation/initialization fails; update the failure path where the display is set to NONE or init fails (the block around the display allocation/initialization at lines ~253-260) to disable Vext by calling digitalWrite(HELTEC_VEXT_PIN, HIGH) (inside the existing `#ifdef` HELTEC_VEXT_PIN) so the pin is turned off when you set the display to NONE or when initialization fails.
218-221: ⚡ Quick winConsider using PinManager for HELTEC_VEXT_PIN to maintain consistent resource tracking.
This usermod allocates SPI pins via
PinManager::allocateMultiplePins()(line 230) but bypasses PinManager for the Vext power control pin. While GPIO36 is dedicated to external power on Heltec boards and has no conflicting usage elsewhere, usingPinManager::allocatePin()would make resource tracking uniform across the usermod and follow the pattern established for display pins. This also provides proper cleanup semantics if the usermod is disabled.Suggested improvement
`#ifdef` HELTEC_VEXT_PIN - pinMode(HELTEC_VEXT_PIN, OUTPUT); - digitalWrite(HELTEC_VEXT_PIN, LOW); + if (PinManager::allocatePin(HELTEC_VEXT_PIN, true, PinOwner::UM_FourLineDisplay)) { + pinMode(HELTEC_VEXT_PIN, OUTPUT); + digitalWrite(HELTEC_VEXT_PIN, LOW); + } `#endif`🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@usermods/usermod_v2_four_line_display_ALT/usermod_v2_four_line_display_ALT.cpp` around lines 218 - 221, The HELTEC_VEXT_PIN is configured directly with pinMode/digitalWrite instead of using PinManager, causing inconsistent resource tracking; replace the direct pin setup with PinManager::allocatePin(HELTEC_VEXT_PIN, PinOwner::Usermod) (matching the existing allocateMultiplePins usage) then set the pin mode and initial state via the allocated pin, and ensure you release it on disable/cleanup (e.g., in the usermod disable/shutdown path) so allocation and cleanup match the display pins managed by PinManager.
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In
`@usermods/usermod_v2_four_line_display_ALT/usermod_v2_four_line_display_ALT.cpp`:
- Around line 218-221: Display power (HELTEC_VEXT_PIN) is left enabled
(digitalWrite(HELTEC_VEXT_PIN, LOW)) even when display allocation/initialization
fails; update the failure path where the display is set to NONE or init fails
(the block around the display allocation/initialization at lines ~253-260) to
disable Vext by calling digitalWrite(HELTEC_VEXT_PIN, HIGH) (inside the existing
`#ifdef` HELTEC_VEXT_PIN) so the pin is turned off when you set the display to
NONE or when initialization fails.
- Around line 218-221: The HELTEC_VEXT_PIN is configured directly with
pinMode/digitalWrite instead of using PinManager, causing inconsistent resource
tracking; replace the direct pin setup with
PinManager::allocatePin(HELTEC_VEXT_PIN, PinOwner::Usermod) (matching the
existing allocateMultiplePins usage) then set the pin mode and initial state via
the allocated pin, and ensure you release it on disable/cleanup (e.g., in the
usermod disable/shutdown path) so allocation and cleanup match the display pins
managed by PinManager.
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usermods/usermod_v2_four_line_display_ALT/usermod_v2_four_line_display_ALT.cpp
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Summary
Added complete OLED display support for the Heltec WiFi LoRa 32 V3 board with automatic GPIO36 (Vext) power control. This includes the four_line_display_ALT usermod with GPIO36 initialization to enable the onboard 0.96" SSD1306 display without manual wiring.
Changes
platformio_override.ini: Created custom environment for Heltec V3 with OLED support
usermod_v2_four_line_display_ALT.cpp: Added GPIO36 power control
Features
✅ No PSRAM required (fixed Error 8 memory issue)
✅ Integrated SSD1306 OLED display support
✅ Automatic Vext power control (GPIO36)
✅ I2C display on GPIO17/GPIO18
✅ Memory optimized for ESP32-S3
Testing
Related Releases
Summary by CodeRabbit