start of the epd. Problem right now 0xff display black. Will have to investigate

2026-03-29 21:36:37 -04:00
parent e5b72bbb20
commit be735990ff
14 changed files with 4498 additions and 35 deletions
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+# EPD Reference Driver — GDEY075T7 (UC8179)
+
+## Source
+
+**Repository:** [ekosboard/firmware](https://github.com/ekosboard/firmware)  
+**File:** [`src/components/EPD/driver/epd_GDEY075T7.c`](https://github.com/ekosboard/firmware/blob/main/src/components/EPD/driver/epd_GDEY075T7.c)
+
+## Panel Info
+
+- **Controller:** UC8179
+- **Panel:** GDEY075T7 (Good Display 7.5" B/W, 800×480)
+- **Platform:** ESP-IDF (native SPI)
+- **Grayscale:** 4-level support present but marked as "NOT TESTED"
+
+## Key Implementation Details
+
+### BUSY Pin Polarity
+- **Reference driver:** HIGH = Busy, LOW = Idle
+- **⚠️ Our board is INVERTED:** LOW = Busy, HIGH = Idle
+- Wait loop polls `gpio_get_level(BUSY) == 0` to detect idle (reference)
+- Our code uses `== 0` to wait while busy (opposite meaning, same code pattern)
+
+### Clear Screen (White)
+- Writes `0xFF` to **both** old (0x10) and new (0x13) data layers
+- `0xFF` = White, `0x00` = Black
+
+### Display Image
+- Writes `0x00` to old data layer (0x10) — assumes previous state was black
+- Writes actual image data to new data layer (0x13)
+
+### Sleep Sequence
+1. `0x50` with `0xF7` — VCOM and data interval setting before sleep
+2. `0x02` — Power Off
+3. Wait for BUSY idle
+4. `0x07` + `0xA5` — Deep Sleep
+
+### Init Sequence (Full Refresh)
+1. Hardware reset (RST low 10ms, high 10ms)
+2. `0x01` — Power Setting: VGH=20V, VGL=-20V, VDH=15V, VDL=-15V, VDHR=4.2V
+3. `0x06` — Booster Soft Start: 0x17, 0x17, 0x28, 0x17
+4. `0x04` — Power On + 100ms delay + wait busy
+5. `0x00` — Panel Setting: `0x1F` (KW B/W mode)
+6. `0x61` — Resolution: 800×480
+7. `0x15` — DUSPI disabled
+8. `0x50` — VCOM: 0x10, 0x07
+9. `0x60` — TCON: 0x22
+10. `0xE3` — PWS: 0x22
+
+### Fast Refresh
+- `0xE0` → `0x02` (enable fast mode)
+- `0xE5` → `0x5A` (fast refresh timing)
+
+### Partial Update
+- Uses `0x91` (partial in) / `0x92` (partial out) + `0x90` (resolution setting)
+- Writes `~data` (inverted) to old layer to force transitions
+- Sets `0x50` → `0x21` (N2OCP disabled) for partial mode
+
+### 4-Level Grayscale
+- Requires different booster settings: `0x27, 0x27, 0x18, 0x17`
+- `0xE5` → `0x5F` for grayscale timing
+- Data encoding: 2 bits per pixel (0xC0=white, 0x00=black, 0x80=gray1, 0x40=gray2)
+- Old layer and new layer encode different bit planes, both inverted (`~temp3`)