1.8 inch TFT (ST7735): specs and pinout
ST7735S single-chip TFT controller and driver for small colour LCD panels, controlled over a serial or 8080-style parallel interface.
Specs
| Spec | Value | Source |
|---|---|---|
| System supply VDD (analog) | 2.5 V to 4.8 V (2.75 V typ) | source Section 7.2 DC Characteristic (p.29) |
| Interface supply VDDI (I/O) | 1.65 V to 3.7 V (1.8 V typ) | source Section 7.2 DC Characteristic (p.29); features (p.11) |
| Source voltage GVDD | 3.15 V to 5 V | source Features, on-chip power system (p.11) |
| Gate driver high level VGH | +10.0 V to +15 V | source Features, on-chip power system (p.11) |
| Controller frame memory and panel size | 132 RGB x 162 dots (GM = 00); 128 RGB x 160 mode (GM = 11) | source Cover page (p.1); section 9.9.3 (p.68) |
| Colour depth | 262K colours | source Cover page (p.1) |
Power
| Value | Source | |
|---|---|---|
| Supply | VDD 2.5-4.8 V; VDDI 1.65-3.7 V (chip ratings) | source Section 7.3 Power Consumption, Table 3 (p.30); values not given |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently. Module header labels come from the Compoden listing, not an official module schematic.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| VDD | Power supply for analog, digital system and booster circuit | 2.5-4.8 V (2.75 V typ) per Section 7.2 DC Characteristic | source Section 6 Pin Description (p.23-24); Section 7.2 (p.29) | |
| VDDI | Power supply for I/O system | 1.65-3.7 V (1.8 V typ); logic VIH min 0.7 x VDDI, VIL max 0.3 x VDDI | Logic input absolute max -0.3 V to VDDI + 0.3 V; 5 V SPI lines exceed this. | source Section 6 Pin Description (p.23-24); Section 7.1 Absolute Operation Range (p.28); Section 7.2 (p.29) |
| AGND / DGND | System ground for analog+booster / for I/O+digital system | 0 V | source Section 6 Pin Description (p.23-24) | |
| RESX | Reset, active LOW; must be applied to initialise | Logic input, max VDDI + 0.3 V | source Section 6 Pin Description (p.23-24) | |
| CSX | Chip select, low enable | Logic input, max VDDI + 0.3 V | source Section 6 Pin Description (p.23-24) | |
| D/CX (SCL) | Display data/command select in MCU interface; in serial interface used as SCL | Logic input, max VDDI + 0.3 V | source Section 6 Pin Description (p.23-24) | |
| WRX (D/CX) | Write enable in MCU parallel interface; in 4-line SPI used as D/CX (data/command) | Logic input, max VDDI + 0.3 V | source Section 6 Pin Description (p.23-24) | |
| D0 | Serial input/output signal in serial interface mode | Logic I/O, max VDDI + 0.3 V | In serial interface D[17:1] are not used and should be fixed at VDDI or DGND. | source Section 6 Pin Description (p.23-24) |
Common mistakes
- Driving 5 V logic into the module: the I/O supply VDDI is 1.65-3.7 V, so 5 V SCK, MOSI, CS or DC lines need a level shifter (source)
- Reading the 128 x 160 size as the controller's native size: the controller datasheet describes 132 x 162 RGB dots, with 128 x 160 as a selectable mode (source)
- Using the VDD range for a 3.3-5 V module: VDD is 2.5-4.8 V on the chip and the module's board supply is not in the datasheet (source)
What we could not confirm
- Controller variant of the module (ST7735R or ST7735S) is not identified; these values are ST7735S.
- Module-level 3.3-5 V supply: not in datasheet.
- Power consumption table (Table 3) values are not given on this page.
- Module header pins are not covered by the chip datasheet.
- Module header: the listing gives NO pin labels for this board (it says only 'needs at least 4 IO' and mentions an onboard microSD slot), so no module labels are given. The pin rows above are the CHIP's serial-interface pins; module pin names, order and the backlight/microSD pins are unsourced.
- Spec row 'Gate driver high level VGH +10.0 V to +15 V' differs from Section 7.2 DC characteristics in the datasheet (VGH 11 V min, 16 V max; VGL -13 to -7.5 V). Check the PDF for the exact figures.
- Chip logic is VDDI 1.65-3.7 V; the listing's '3.3-5V input' is a module-level claim and 5 V SPI signalling is not supported by the datasheet.
Sources
- link (Sitronix ST7735S Version 1.1, 2011-11-21; carries a Crystalfontz banner)
- Copy of the Sitronix ST7735S datasheet hosted by a hosted copy. The Sitronix site (link) has no direct PDF.
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