An Arduino library for the CST816S capacitive touch screen IC
Auto Sleep is referred to as Standby Mode in this Waveshare document. Disabling of auto sleep or auto standby will keep the touch display in Dynamic mode. This will improve responsiveness, at the cost of about ~1.6mA.
By default, auto sleep is enabled with a timeout of 2 seconds. The following functions allow you to manage auto sleep behavior:
-
void disable_auto_sleep();
Disables auto sleep, keeping the device active indefinitely. -
void enable_auto_sleep();
Re-enables auto sleep with the current timeout (default is 2 seconds). -
void set_auto_sleep_time(int seconds);
Sets the auto sleep timeout in seconds (1-255).
Example:set_auto_sleep_time(10);sets a 10-second timeout.
The CST816S library allows you to attach a custom interrupt function to handle touch events according to your application's needs. By providing a user-defined interrupt, you can trigger specific actions upon touch events, such as waking the device from a low-power state, checking gestures, or executing custom logic without constantly polling the device.
Feature Highlights:
- Custom Event Handling: Define and attach a user function that executes on each touch interrupt, allowing immediate responses to touch events.
- Power Management: Ideal for applications needing to manage power, such as waking from sleep modes, as the interrupt triggers only on touch.
- Gesture-Based Logic: Use the interrupt to wake, then analyze gestures to decide on further actions, enabling efficient and gesture-responsive behavior.
The following information was extracted from this document provided by Waveshare.
| Register Name | Address | Bit Description | Default Value | Configuration Options |
|---|---|---|---|---|
| GestureID | 0x01 | Gesture code for detected gestures | N/A | - 0x00: None - 0x01: Slide Up - 0x02: Slide Down - 0x03: Slide Left - 0x04: Slide Right - 0x05: Single Click - 0x0B: Double Click - 0x0C: Long Press |
| FingerNum | 0x02 | Number of fingers detected | N/A | - 0: No finger - 1: One finger |
| XposH | 0x03 | High 4 bits of X coordinate | N/A | - |
| XposL | 0x04 | Low 8 bits of X coordinate | N/A | - |
| YposH | 0x05 | High 4 bits of Y coordinate | N/A | - |
| YposL | 0x06 | Low 8 bits of Y coordinate | N/A | - |
| BPC0H | 0xB0 | High 8 bits of BPC0 value | N/A | - |
| BPC0L | 0xB1 | Low 8 bits of BPC0 value | N/A | - |
| BPC1H | 0xB2 | High 8 bits of BPC1 value | N/A | - |
| BPC1L | 0xB3 | Low 8 bits of BPC1 value | N/A | - |
| ChipID | 0xA7 | Chip model identifier | N/A | - |
| ProjID | 0xA8 | Project number | N/A | - |
| FwVersion | 0xA9 | Firmware version number | N/A | - |
| MotionMask | 0xEC | Enable continuous gesture actions and double-click | 0x00 | - Bit 0: EnDClick (enable double-click) - Bit 1: EnConUD (enable continuous up/down swipe) - Bit 2: EnConLR (enable continuous left/right swipe) |
| IrqPluseWidth | 0xED | Interrupt pulse width (0.1 ms units) | 10 | 1-200 |
| NorScanPer | 0xEE | Normal scan period (10 ms units) | 1 | 1-30 |
| MotionSlAngle | 0xEF | Gesture detection sliding angle control (Angle = tan(c) * 10, where c is the angle relative to the positive X-axis) | N/A | - |
| LpScanRaw1H | 0xF0 | High 8 bits of low-power scan channel 1 reference | N/A | - |
| LpScanRaw1L | 0xF1 | Low 8 bits of low-power scan channel 1 reference | N/A | - |
| LpScanRaw2H | 0xF2 | High 8 bits of low-power scan channel 2 reference | N/A | - |
| LpScanRaw2L | 0xF3 | Low 8 bits of low-power scan channel 2 reference | N/A | - |
| LpAutoWakeTime | 0xF4 | Low-power mode auto recalibration interval (in minutes) | 5 minutes | 1-5 minutes |
| LpScanTH | 0xF5 | Low-power scan wake threshold. The smaller the value, the more sensitive it is. | 48 | 1-255 |
| LpScanWin | 0xF6 | Low-power scan range. The larger the value, the more sensitive it is, but power consumption increases. | 3 | 0-3 |
| LpScanFreq | 0xF7 | Low-power scan frequency. The smaller the value, the more sensitive it is. | 7 | 1-255 |
| LpScanIdac | 0xF8 | Low-power scan current. The smaller the value, the more sensitive it is. | N/A | 1-255 |
| AutoSleepTime | 0xF9 | Time in seconds before entering standby mode after inactivity | 2 seconds | 1-255 seconds |
| IrqCtl | 0xFA | Control of interrupt behavior | N/A | - Bit 7: EnTest (Enable test, periodically sends low pulses) - Bit 6: EnTouch (Sends low pulse on touch detection) - Bit 5: EnChange (Sends low pulse on touch state change) - Bit 4: EnMotion (Sends low pulse on gesture detection) - Bit 0: OnceWLP (Sends one low pulse on long press) |
| AutoReset | 0xFB | Auto-reset time after detecting touch with no valid gesture | 5 seconds | - 0: Disable - 1-5: Time in seconds before auto-reset |
| LongPressTime | 0xFC | Time (in seconds) for a long press to trigger reset | 10 seconds | - 0: Disable - 1-10: Long press duration in seconds |
| IOCtl | 0xFD | IO control settings including soft reset and power options | N/A | - Bit 2: SOFT_RST (0: Disable soft reset, 1: Enable soft reset) - Bit 1: IIC_OD (0: Pull-up resistor, 1: Open-drain) - Bit 0: En1v8 (0: VDD, 1: 1.8V) |
| DisAutoSleep | 0xFE | Disable automatic entry into low-power mode | 0 (enabled) | - 0: Enable auto sleep - Non-zero: Disable auto sleep |