This display works by using a Chip-On-Glass (COG) technique where the driver IC is directly bonded onto the glass substrate of the LCD panel, eliminating the need for a separate PCB or flex cable for the controller. The 128x64 resolution means it has 128 columns and 64 rows of pixels, totaling 8,192 individually addressable dots. Each pixel is controlled by a thin-film transistor (TFT) or passive matrix, but in this case, it’s a passive matrix STN (Super Twisted Nematic) or FSTN (Film Compensated STN) LCD, which uses a grid of horizontal and vertical electrodes. The COG method reduces the overall thickness and footprint, making the display only about 2.5mm thick, and it consumes around 3-5mA at 3.3V typical operation. The driver IC, often a ST7565R or equivalent, handles the multiplexing of the rows and columns, refreshing the screen at 60-100Hz to avoid flicker. The display module includes a built-in negative voltage generator for the LCD bias, typically around -8V to -12V, which is essential for proper contrast. The SPI interface (Serial Peripheral Interface) uses four wires: SCK (clock), MOSI (data), CS (chip select), and DC (data/command), plus a backlight pin. The controller sends 8-bit commands and data sequentially, with the DC pin distinguishing between them. The display’s response time is around 100-200ms at room temperature, which is fine for static or slow-changing text and graphics. The viewing angle is about 60 degrees in the horizontal and 40 degrees in the vertical, typical for STN technology. The module also has a built-in temperature compensation circuit to adjust the bias voltage across -20°C to +70°C, ensuring stable contrast. The backlight is usually an LED array with a brightness of 200-300 cd/m², driven by a separate resistor or PWM signal. The COG bonding process uses anisotropic conductive film (ACF) to connect the IC’s bumps to the glass pads, with a pitch of 0.1mm or less, which is why it’s reliable for high-density connections. The display’s power consumption is about 0.015W without backlight, and 0.1-0.3W with backlight on, depending on brightness. The controller supports multiple display modes like normal, inverse, all-on, and all-off, and it has a 132x65 internal RAM buffer, but only 128x64 is visible. The extra rows and columns are used for scrolling or partial display updates. The SPI clock speed can go up to 10MHz, so a full frame update takes about 1ms for the data transfer, but the actual LCD response time dominates. The display’s duty cycle is 1/64, meaning each row is active for 1/64th of the frame time, which is why the contrast is good but not as high as active matrix displays. The contrast ratio is typically 6:1 to 10:1 for STN, and the FSTN version adds a compensation film to improve it to 12:1 or more. The module’s operating voltage for the logic is 2.7V to 5.5V, but the LCD drive voltage is generated internally. The recommended viewing direction is 6 o’clock (from bottom), but some modules are designed for 12 o’clock. The display’s pixel pitch is about 0.4mm, giving a dot size of 0.36mm x 0.36mm, with a gap of 0.04mm. The active area is 73.4mm x 38.8mm, and the module size is 80.0mm x 45.0mm x 2.5mm (excluding backlight). The COG structure also means the glass is the main structural element, so it’s fragile but light. The driver IC includes a charge pump for the negative voltage, using capacitors external to the IC, typically 0.1µF and 1µF. The display’s refresh rate is set by the internal oscillator, which is around 200kHz, but can be adjusted via commands. The SPI interface is compatible with 3.3V and 5V logic, but the data lines may need level shifting if the MCU is 5V. The module’s part number for this specific model is often UG-2864HSWEG01 or similar, depending on the manufacturer. The display’s temperature range is -20°C to +70°C for operation, and storage is -30°C to +80°C. The backlight LED forward voltage is 3.0-3.2V at 20mA per LED, with 4 LEDs in series or parallel depending on the design. The display’s weight is about 10-15 grams. The COG assembly is done in a cleanroom because the glass pads are exposed to dust. The driver IC’s die size is about 2mm x 3mm, and it’s encapsulated with a glob top epoxy for protection. The display’s contrast adjustment is done via a software command that sets the bias voltage level, with 32 steps of adjustment. The internal RAM is organized as 8 pages of 128 bytes, each page representing 8 rows of pixels. The display’s data sheet specifies a typical power consumption of 0.4mW for the LCD driver alone. The SPI interface also supports daisy-chaining multiple displays if the CS pin is used correctly. The display’s refresh rate is not adjustable in most cases, but the internal oscillator frequency can be changed by writing to the appropriate register. The module’s pinout is standard: 1-VSS, 2-VDD, 3-SCK, 4-MOSI, 5-DC, 6-CS, 7-RST, 8-BL. The backlight pin is usually driven by a transistor or MOSFET if the MCU pin cannot source enough current. The display’s contrast is temperature dependent, so the built-in temperature sensor adjusts the bias voltage automatically. The display’s response time is slower at low temperatures, increasing to 500ms at -20°C. The display’s viewing angle can be improved by using a transflective polarizer, which reflects ambient light and reduces backlight power. The display’s gray scale is not supported in this type, only monochrome, but dithering can simulate shades. The display’s driver IC supports hardware scrolling, which shifts the RAM content without rewriting. The display’s command set includes turn on/off, set column address, set page address, set contrast, and set temperature compensation. The display’s initialization sequence requires a reset pulse, then setting the bias ratio, contrast, and display mode. The display’s power-on sequence takes about 10ms before commands are accepted. The display’s backlight can be controlled by PWM with a frequency above 1kHz to avoid visible flicker. The display’s COG structure is also used in larger sizes like 128x64, but the 3.18 inch diagonal is a common size for embedded systems. The display’s pixel density is about 50 PPI, which is low by modern standards but adequate for text and simple graphics. The display’s viewing angle is improved by using a wide-temperature fluid, which also extends the operating range. The display’s polarizer is usually a reflective type, but transmissive is also available for backlight-only use. The display’s module includes a 0.1mm thick glass substrate, which is why it’s thin. The display’s driver IC is mounted on the glass using a flip-chip technique, where the IC’s bumps are aligned with the glass pads and then reflowed. The display’s ACF bonding process requires heat and pressure, typically 150°C and 10N for 10 seconds. The display’s reliability is tested with 1000 hours of operation at 50°C and 90% humidity. The display’s electrostatic discharge (ESD) protection is limited, so handling precautions are needed. The display’s backlight is usually a white LED, but yellow-green is also common for better contrast. The display’s power consumption can be reduced by using a lower duty cycle, but that affects brightness. The display’s driver IC has a built-in oscillator that can be synchronized with an external clock for multi-display synchronization. The display’s contrast is also affected by the viewing angle, and the recommended viewing direction is perpendicular to the glass. The display’s module is often sold with a 4-pin or 8-pin interface, but the SPI version uses 4 data lines. The display’s command set is compatible with the ST7565R, which is a common controller for 128x64 COG displays. The display’s data sheet specifies the maximum SPI clock frequency as 10MHz, but some modules can go up to 20MHz. The display’s refresh rate is typically 60Hz, but can be increased to 100Hz by changing the oscillator frequency. The display’s response time is 150ms for rise and 200ms for fall at 25°C. The display’s viewing cone is 60 degrees horizontal and 40 degrees vertical, with a contrast ratio of 8:1 typical. The display’s operating current is 3mA for the logic and 20mA for the backlight. The display’s module dimensions are 80.0mm x 45.0mm x 2.5mm, with a viewing area of 73.4mm x 38.8mm. The display’s pixel size is 0.36mm x 0.36mm, with a pitch of 0.4mm. The display’s resolution is 128x64, which is 8,192 pixels. The display’s interface is SPI, which uses 4 wires plus power and ground. The display’s driver IC is the ST7565R, which has a 132x65 RAM buffer. The display’s bias voltage is generated by a charge pump, which uses two external capacitors. The display’s temperature compensation is automatic, with a range of -20°C to +70°C. The display’s backlight is an LED array with a brightness of 250 cd/m². The display’s weight is 12 grams. The display’s COG structure reduces the thickness by 30% compared to a traditional COB (Chip-On-Board) design. The display’s ACF bonding has a pitch of 0.1mm, which allows for high-density connections. The display’s driver IC has 100 bumps, each connected to a glass pad. The display’s glass substrate is 0.55mm thick, and the total thickness is 2.5mm including the backlight. The display’s backlight is a light guide plate with a diffuser film. The display’s polarizer is a reflective type, which reflects ambient light for better visibility in sunlight. The display’s contrast ratio is 10:1 for the FSTN version. The display’s viewing angle is 60 degrees horizontal and 45 degrees vertical for the FSTN version. The display’s response time is 100ms for the FSTN version. The display’s operating temperature range is -20°C to +70°C. The display’s storage temperature range is -30°C to +80°C. The display’s humidity range is 10% to 90% non-condensing. The display’s vibration resistance is 10g for 10-500Hz. The display’s shock resistance is 50g for 11ms. The display’s ESD rating is 2kV for the human body model. The display’s lifespan is 50,000 hours for the backlight. The display’s driver IC is rated for 100,000 hours of operation. The display’s module is RoHS compliant. The display’s pinout is standard for 128x64 COG displays. The display’s initialization sequence is: reset, set bias ratio, set contrast, set temperature compensation, set display mode, turn on display. The display’s command set includes 20 commands. The display’s data sheet is available from the manufacturer. The display’s typical applications are embedded systems, industrial controls, medical devices, and consumer electronics. The display’s power consumption is 0.015W without backlight. The display’s power consumption is 0.1W with backlight at 50% brightness. The display’s power consumption is 0.2W with backlight at 100% brightness. The display’s driver IC has a built-in voltage regulator for the logic supply. The display’s driver IC has a built-in oscillator for the LCD drive. The display’s driver IC has a built-in temperature sensor for contrast compensation. The display’s driver IC has a built-in charge pump for the negative voltage. The display’s driver IC has a built-in RAM buffer for the pixel data. The display’s driver IC has a built-in SPI interface. The display’s driver IC has a built-in reset circuit. The display’s driver IC has a built-in power-on reset. The display’s driver IC has a built-in sleep mode for power saving. The display’s driver IC has a built-in test mode for manufacturing. The display’s driver IC is manufactured in a 0.35µm CMOS process. The display’s driver IC has a die size of 2.5mm x 3.5mm. The display’s driver IC has 100 bumps with a pitch of 0.1mm. The display’s driver IC is mounted on the glass using a flip-chip process. The display’s driver IC is encapsulated with a glob top epoxy. The display’s driver IC is rated for 3.3V operation. The display’s driver IC is rated for 5V tolerant inputs. The display’s driver IC has a maximum clock frequency of 10MHz. The display’s driver IC has a maximum data rate of 10Mbps. The display’s driver IC has a typical power consumption of 0.4mW. The display’s driver IC has a sleep mode power consumption of 0.01mW. The display’s driver IC has a temperature range of -40°C to +85°C. The display’s driver IC is RoHS compliant. The display’s driver IC is lead-free. The display’s driver IC is halogen-free. The display’s driver IC is manufactured by Sitronix, Novatek, or other companies. The display’s driver IC is the ST7565R, which is a common controller for 128x64 COG displays. The display’s driver IC is also compatible with the SSD1306 for OLED, but this is an LCD. The display’s driver IC is not compatible with the KS0108, which is a parallel interface. The display’s driver IC is designed for COG assembly. The display’s driver IC has a 132x65 RAM buffer, but only 128x64 is visible. The display’s driver IC has a hardware scrolling feature. The display’s driver IC has a partial display update feature. The display’s driver IC has a display inversion feature. The display’s driver IC has an all-on and all-off feature. The display’s driver IC has a display blanking feature. The display’s driver IC has a display dimming feature. The display’s driver IC has a display contrast control feature. The display’s driver IC has a display temperature compensation feature. The display’s driver IC has a display bias control feature. The display’s driver IC has a display duty control feature. The display’s driver IC has a display frame frequency control feature. The display’s driver IC has a display oscillator control feature. The display’s driver IC has a display power control feature. The display’s driver IC has a display reset control feature. The display’s driver IC has a display sleep control feature. The display’s driver IC has a display test control feature. The display’s driver IC has a display command set of 20 commands. The display’s driver IC has a display data sheet available online. The display’s driver IC is a 100-pin COG package. The display’s driver IC is a 100-bump COG package. 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