Files
crosspoint-reader-mod/lib/hal/HalGPIO.h
Xuan-Son Nguyen 6ec5fc5603 feat: lower CPU freq on idle, add HalPowerManager (#852)
## Summary

Continue my experiment from
https://github.com/crosspoint-reader/crosspoint-reader/pull/801

This PR add the ability to lower the CPU frequency on extended idle
period (currently set to 3 seconds). By default, the esp32c3 CPU is set
to 160MHz, and now on idle, we can reduce it to just 10MHz.

Note that while this functionality is already provided by [esp power
management](https://docs.espressif.com/projects/esp-idf/en/v4.3/esp32c3/api-reference/system/power_management.html),
the current Arduino build lacks of this, and enabling it is just too
complicated (not worth the effort compared to this PR)

Update: more info in
https://github.com/crosspoint-reader/crosspoint-reader/pull/852#issuecomment-3904562827

## Testing

Pre-condition for each test case: the battery is charged to 100%, and is
left plugged in after fully charged for an extra 1 hour.

The table below shows how much battery is **used** for a given duration:

| case / duration | 6 hrs | 12 hrs |
| --- | --- | --- |
| `delay(10)` | 26% | 48% |
| `delay(50)`, PR
https://github.com/crosspoint-reader/crosspoint-reader/pull/801 | 20% |
Not tested |
| `delay(50)` + low CPU freq (This PR) | Not tested | 25% |
| `delay(10)` + low CPU freq (1) | Not tested | Not tested |

(1) I decided not to test this case because it may not make sense. The
problem is that CPU frequency vs power consumption do not follow a
linear relationship, see
[this](https://www.arrow.com/en/research-and-events/articles/esp32-power-consumption-can-be-reduced-with-sleep-modes)
as an example. So, tight loop (10ms) + lower CPU freq significantly
impact battery life, because the active CPU time is now much higher
compared to the wall time.

**So in conclusion, this PR improves ~150% to ~200% battery use time per
charge.**

The projected battery life is now: ~36-48 hrs of reading time (normal
reading, no wifi)

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? **NO**
2026-02-18 17:12:29 +03:00

57 lines
1.5 KiB
C++

#pragma once
#include <Arduino.h>
#include <BatteryMonitor.h>
#include <InputManager.h>
// Display SPI pins (custom pins for XteinkX4, not hardware SPI defaults)
#define EPD_SCLK 8 // SPI Clock
#define EPD_MOSI 10 // SPI MOSI (Master Out Slave In)
#define EPD_CS 21 // Chip Select
#define EPD_DC 4 // Data/Command
#define EPD_RST 5 // Reset
#define EPD_BUSY 6 // Busy
#define SPI_MISO 7 // SPI MISO, shared between SD card and display (Master In Slave Out)
#define BAT_GPIO0 0 // Battery voltage
#define UART0_RXD 20 // Used for USB connection detection
class HalGPIO {
#if CROSSPOINT_EMULATED == 0
InputManager inputMgr;
#endif
public:
HalGPIO() = default;
// Start button GPIO and setup SPI for screen and SD card
void begin();
// Button input methods
void update();
bool isPressed(uint8_t buttonIndex) const;
bool wasPressed(uint8_t buttonIndex) const;
bool wasAnyPressed() const;
bool wasReleased(uint8_t buttonIndex) const;
bool wasAnyReleased() const;
unsigned long getHeldTime() const;
// Check if USB is connected
bool isUsbConnected() const;
enum class WakeupReason { PowerButton, AfterFlash, AfterUSBPower, Other };
WakeupReason getWakeupReason() const;
// Button indices
static constexpr uint8_t BTN_BACK = 0;
static constexpr uint8_t BTN_CONFIRM = 1;
static constexpr uint8_t BTN_LEFT = 2;
static constexpr uint8_t BTN_RIGHT = 3;
static constexpr uint8_t BTN_UP = 4;
static constexpr uint8_t BTN_DOWN = 5;
static constexpr uint8_t BTN_POWER = 6;
};