From ae0949895354340f6592113ce3bd15d2b1112fcd Mon Sep 17 00:00:00 2001
From: ZodiusInfuser <christopher.parrott2@gmail.com>
Date: Wed, 18 Aug 2021 12:16:51 +0100
Subject: [PATCH] Added analog class for plasma current reading

---
 drivers/CMakeLists.txt        |  1 +
 drivers/analog/CMakeLists.txt |  1 +
 drivers/analog/analog.cmake   | 11 +++++++++++
 drivers/analog/analog.cpp     | 18 ++++++++++++++++++
 drivers/analog/analog.hpp     | 31 +++++++++++++++++++++++++++++++
 5 files changed, 62 insertions(+)
 create mode 100644 drivers/analog/CMakeLists.txt
 create mode 100644 drivers/analog/analog.cmake
 create mode 100644 drivers/analog/analog.cpp
 create mode 100644 drivers/analog/analog.hpp

diff --git a/drivers/CMakeLists.txt b/drivers/CMakeLists.txt
index 58a2bbd3..88d0b099 100644
--- a/drivers/CMakeLists.txt
+++ b/drivers/CMakeLists.txt
@@ -1,3 +1,4 @@
+add_subdirectory(analog)
 add_subdirectory(esp32spi)
 add_subdirectory(ioexpander)
 add_subdirectory(ltp305)
diff --git a/drivers/analog/CMakeLists.txt b/drivers/analog/CMakeLists.txt
new file mode 100644
index 00000000..06d94443
--- /dev/null
+++ b/drivers/analog/CMakeLists.txt
@@ -0,0 +1 @@
+include(analog.cmake)
\ No newline at end of file
diff --git a/drivers/analog/analog.cmake b/drivers/analog/analog.cmake
new file mode 100644
index 00000000..69caf0a6
--- /dev/null
+++ b/drivers/analog/analog.cmake
@@ -0,0 +1,11 @@
+set(DRIVER_NAME analog)
+add_library(${DRIVER_NAME} INTERFACE)
+
+target_sources(${DRIVER_NAME} INTERFACE
+  ${CMAKE_CURRENT_LIST_DIR}/${DRIVER_NAME}.cpp
+)
+
+target_include_directories(${DRIVER_NAME} INTERFACE ${CMAKE_CURRENT_LIST_DIR})
+
+# Pull in pico libraries that we need
+target_link_libraries(${DRIVER_NAME} INTERFACE pico_stdlib hardware_adc)
\ No newline at end of file
diff --git a/drivers/analog/analog.cpp b/drivers/analog/analog.cpp
new file mode 100644
index 00000000..f3179a7e
--- /dev/null
+++ b/drivers/analog/analog.cpp
@@ -0,0 +1,18 @@
+#include "analog.hpp"
+
+namespace pimoroni {
+    uint16_t Analog::read_raw() {
+      return adc_read();
+    }
+
+    float Analog::read_voltage() {
+      return ((float)adc_read() * 3.3f) / (1 << 12) / amplifier_gain;
+    }
+
+    float Analog::read_current() {
+      if(resistor > 0.0f)
+        return read_voltage() / resistor;
+      else
+        return read_voltage();
+    }
+};
\ No newline at end of file
diff --git a/drivers/analog/analog.hpp b/drivers/analog/analog.hpp
new file mode 100644
index 00000000..cad26e46
--- /dev/null
+++ b/drivers/analog/analog.hpp
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <stdint.h>
+#include "pico/stdlib.h"
+#include "hardware/adc.h"
+#include "common/pimoroni_common.hpp"
+
+namespace pimoroni {
+
+  class Analog {
+  public:
+    Analog(uint pin, float amplifier_gain = 1.0f, float resistor = 0.0f) :
+    pin(pin), amplifier_gain(amplifier_gain), resistor(resistor) {
+      adc_init();
+
+      //Make sure GPIO is high-impedance, no pullups etc
+      adc_gpio_init(pin);
+
+      //Select ADC input 0 (GPIO26)
+      adc_select_input(pin - 26);
+    };
+    uint16_t read_raw();
+    float read_voltage();
+    float read_current();
+  private:
+    uint pin;
+    float amplifier_gain;
+    float resistor;
+  };
+
+}
\ No newline at end of file