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Workaround for when USB CDC is unplugged #7583

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Merged
merged 4 commits into from
Dec 14, 2022
Merged

Workaround for when USB CDC is unplugged #7583

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f3ed691
Workaround for when USB CDC is unplugged
SuGlider Dec 12, 2022
88f7a5e
Considers default TX timeout
SuGlider Dec 13, 2022
f8ed7eb
fixed left over code
SuGlider Dec 13, 2022
4a2da36
Merge branch 'master' into USB-CDC-Unplugged
SuGlider Dec 13, 2022
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2 changes: 1 addition & 1 deletion cores/esp32/HWCDC.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ static uint8_t rx_data_buf[64];
static intr_handle_t intr_handle = NULL;
static volatile bool initial_empty = false;
static xSemaphoreHandle tx_lock = NULL;
static uint32_t tx_timeout_ms = 200;
static uint32_t tx_timeout_ms = 0; // workaround for when USB CDC is not connected
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with this being 0, it means that is the ring buffer is full, the code will not give it time to empty some space and will just discard the input. Maybe wait if the is not enough space? Fixing it for when USB is disconnected, but breaking it for when connected is not all that nice :)

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Waiting when there is no space (timeout) is exacty the issue... when the board is turned on with the USB unplugged. That is what causes the delay from the point when the RingBuffer gets full and it never is flushed because there is no USB connection.

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There is no event that tells the user that USB is or not plugged. Even the ARDUINO_HW_CDC_CONNECTED_EVENT works only the first time, but if we unplug the board, it doesn't tell anything.

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@me-no-dev - Added code to test if USB is plugged and the application has never changed Tx Timeout. In that case, it will set Tx Timeout to default 100ms.
Otherwise (USB has never been plugged or the Application has explicitly changed Tx Timeout Value), it will keep it zero or the new value set by the application.

static esp_event_loop_handle_t arduino_hw_cdc_event_loop_handle = NULL;

static esp_err_t arduino_hw_cdc_event_post(esp_event_base_t event_base, int32_t event_id, void *event_data, size_t event_data_size, BaseType_t *task_unblocked){
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