Add logic to test VBus connectivity

2 files changed, 21 insertions, 0 deletions

diff --git a/include/fusb302b.h b/include/fusb302b.h
index ce473c5..ad41366 100644
--- a/include/fusb302b.h
+++ b/include/fusb302b.h
@@ -82,6 +82,9 @@ public:
 
   bool runCCLineSelection() const;
 
+  // Measure VBus with the MADC and check if its connected
+  bool isVBUSConnected() const;
+
 private:
   const uint8_t DeviceAddress; // I2C address for this device
   // I2C bus access functions, should return true if command worked
diff --git a/src/fusb302b.cpp b/src/fusb302b.cpp
index 10b5153..c2792f8 100644
--- a/src/fusb302b.cpp
+++ b/src/fusb302b.cpp
@@ -189,6 +189,24 @@ bool FUSB302::runCCLineSelection() const {
   }
   return true;
 }
+
+bool FUSB302::isVBUSConnected() const {
+  // So we want to set MEAS_VBUS to enable measuring the VBus signal
+  // Then check the status
+  uint8_t measureBackup  = fusb_read_byte(FUSB_MEASURE);
+  uint8_t switchesBackup = fusb_read_byte(FUSB_SWITCHES0);
+  // clear MEAS_CCx bits
+  fusb_write_byte(FUSB_SWITCHES0, switchesBackup & 0b11110011);
+  osDelay(10);
+  fusb_write_byte(FUSB_MEASURE, 0b01000000);
+  osDelay(100);
+  uint8_t status = fusb_read_byte(FUSB_STATUS0);
+  // Write back original value
+  fusb_write_byte(FUSB_MEASURE, measureBackup);
+  fusb_write_byte(FUSB_SWITCHES0, switchesBackup);
+  return (status & (0b00100000)) != 0;
+}
+
 bool FUSB302::fusb_get_status(fusb_status *status) const {
 
   /* Read the interrupt and status flags into status */