iterate on gpio expander bit flipping

main/gay-ipod-fw.cpp

@@ -12,7 +12,7 @@
 
 #define I2C_SDA_IO (GPIO_NUM_0)
 #define I2C_SCL_IO (GPIO_NUM_4)
-#define I2C_CLOCK_HZ (400000)
+#define I2C_CLOCK_HZ (100000)
 
 #define SPI_SDI_IO (GPIO_NUM_19)
 #define SPI_SDO_IO (GPIO_NUM_23)
@@ -38,7 +38,7 @@ esp_err_t init_i2c(void) {
     .master = {
       .clk_speed = I2C_CLOCK_HZ,
     },
-    // TODO: check flags
+    // No requirements for the clock.
     .clk_flags = 0,
   };
 
@@ -46,7 +46,6 @@ esp_err_t init_i2c(void) {
   ESP_ERROR_CHECK(i2c_driver_install(port, config.mode, 0, 0, 0));
 
   // TODO: INT line
-  // TODO: add devices to the bus (DAC and GPIO expander)
 
   return ESP_OK;
 }
@@ -84,10 +83,11 @@ extern "C" void app_main(void)
 {
   ESP_LOGI(TAG, "Initialising peripherals");
   init_i2c();
-  init_spi();
+  //init_spi();
 
+  ESP_LOGI(TAG, "Setting default GPIO state");
   gay_ipod::GpioExpander expander;
-  expander.Write();
+  ESP_ERROR_CHECK(expander.Write());
 
-  while (1) {}
+  ESP_LOGI(TAG, "Idling.");
 }

main/gpio-expander.cpp

@@ -38,8 +38,8 @@ esp_err_t GpioExpander::Read() {
   // it because that would indicate some really very badly wrong more generally.
   i2c_master_start(handle);
   i2c_master_write_byte(handle, (PCA8575_ADDRESS << 1 | I2C_MASTER_READ), true);
-  i2c_master_read_byte(handle, &input_a_, I2C_MASTER_ACK);
+  i2c_master_read_byte(handle, &port_a_, I2C_MASTER_ACK);
-  i2c_master_read_byte(handle, &input_b_, I2C_MASTER_LAST_NACK);
+  i2c_master_read_byte(handle, &port_b_, I2C_MASTER_LAST_NACK);
   i2c_master_stop(handle);
 
   esp_err_t ret = i2c_master_cmd_begin(I2C_NUM_0, handle, PCA8575_TIMEOUT);

main/gpio-expander.h

@@ -33,10 +33,10 @@ class GpioExpander {
     GpioExpander& operator=(const GpioExpander&) = delete;
 
   private:
-    // All power switches low, both CS pins high, active-low PWR_OK high.
+    // All power switches high, PWR_OK low (input), both CS pins high.
-    uint8_t port_a_ = 0b00001011;
+    uint8_t port_a_ = uint8_t{0b00001000};
-    // DAC mute output low, everything eelse is input and so held high.
+    // DAC mute output low, everything else is input and so low.
-    uint8_t port_b_ = 0b10111111;
+    uint8_t port_b_ = uint8_t{0b11111111};
 
     uint8_t input_a_ = 0;
     uint8_t input_b_ = 0;