Added AnalogMux to C++

drivers/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_subdirectory(analog)
+add_subdirectory(analogmux)
 add_subdirectory(esp32spi)
 add_subdirectory(ioexpander)
 add_subdirectory(ltp305)

drivers/analogmux/CMakeLists.txt

@@ -0,0 +1 @@
+include(analogmux.cmake)

drivers/analogmux/analogmux.cmake

@@ -0,0 +1,11 @@
+set(DRIVER_NAME analogmux)
+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)

drivers/analogmux/analogmux.cpp

@@ -0,0 +1,80 @@
+#include "analogmux.hpp"
+#include <cstdio>
+
+namespace pimoroni {
+  AnalogMux::AnalogMux(uint addr0_pin, uint addr1_pin, uint addr2_pin,
+                       uint en_pin, uint muxed_pin)
+  : addr0_pin(addr0_pin), addr1_pin(addr1_pin), addr2_pin(addr2_pin)
+  , en_pin(en_pin), muxed_pin(muxed_pin), pull_ups(0), pull_downs(0) {
+
+    gpio_init(addr0_pin);
+    gpio_set_dir(addr0_pin, GPIO_OUT);
+    max_address = 0b001;
+
+    if(addr1_pin != PIN_UNUSED) {
+      gpio_init(addr1_pin);
+      gpio_set_dir(addr1_pin, GPIO_OUT);
+      max_address = 0b011;
+
+      if(addr2_pin != PIN_UNUSED) {
+        gpio_init(addr2_pin);
+        gpio_set_dir(addr2_pin, GPIO_OUT);
+        max_address = 0b111;
+      }
+    }
+
+    if(en_pin != PIN_UNUSED) {
+      gpio_init(en_pin);
+      gpio_set_dir(en_pin, GPIO_OUT);
+    }
+  }
+
+  void AnalogMux::select(uint8_t address) {
+    if(address <= max_address) {
+      bool to_pull_up = (pull_ups & (1u << address));
+      bool to_pull_down = (pull_downs & (1u << address));
+      if((muxed_pin != PIN_UNUSED) && !(to_pull_up || to_pull_down)) {
+        gpio_disable_pulls(muxed_pin);
+      }
+
+      gpio_put(addr0_pin, address & 0b001);
+
+      if(addr1_pin != PIN_UNUSED) {
+        gpio_put(addr1_pin, address & 0b010);
+      }
+
+      if(addr2_pin != PIN_UNUSED) {
+        gpio_put(addr2_pin, address & 0b100);
+      }
+
+      if(en_pin != PIN_UNUSED) {
+        gpio_put(en_pin, true);
+      }
+
+      if((muxed_pin != PIN_UNUSED) && (to_pull_up || to_pull_down)) {
+        gpio_set_pulls(muxed_pin, to_pull_up, to_pull_down);
+      }
+      sleep_us(10); // Add a delay to let the pins settle before taking a reading
+    }
+  }
+
+  void AnalogMux::disable() {
+    if(en_pin != PIN_UNUSED) {
+      gpio_put(en_pin, false);
+    }
+  }
+
+  void AnalogMux::configure_pulls(uint8_t address, bool pullup, bool pulldown) {
+    if(address <= max_address) {
+      if(pullup)
+        pull_ups |= (1u << address);
+      else
+        pull_ups &= ~(1u << address);
+
+      if(pulldown)
+        pull_downs |= (1u << address);
+      else
+        pull_downs &= ~(1u << address);
+    }
+  }
+}

drivers/analogmux/analogmux.hpp

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <stdint.h>
+#include "pico/stdlib.h"
+#include "common/pimoroni_common.hpp"
+
+namespace pimoroni {
+
+  class AnalogMux {
+  public:
+    AnalogMux(uint addr0_pin, uint addr1_pin = PIN_UNUSED, uint addr2_pin = PIN_UNUSED,
+              uint en_pin = PIN_UNUSED, uint muxed_pin = PIN_UNUSED);
+
+    void select(uint8_t address);
+    void disable();
+    void configure_pulls(uint8_t address, bool pullup, bool pulldown);
+
+  private:
+    uint addr0_pin;
+    uint addr1_pin;
+    uint addr2_pin;
+    uint en_pin;
+    uint muxed_pin;
+    uint max_address;
+    uint8_t pull_ups;
+    uint8_t pull_downs;
+  };
+
+}