Turn transmit fifo overwritable in no DTR mode

1 files changed, 4 insertions, 1 deletions

diff --git a/src/class/cdc/cdc_device.c b/src/class/cdc/cdc_device.c
index 91799b2de..6c0f5fc7a 100644
--- a/src/class/cdc/cdc_device.c
+++ b/src/class/cdc/cdc_device.c
@@ -197,7 +197,7 @@ void cdcd_init(void)
 
     // config fifo
     tu_fifo_config(&p_cdc->rx_ff, p_cdc->rx_ff_buf, TU_ARRAY_SIZE(p_cdc->rx_ff_buf), 1, false);
-    tu_fifo_config(&p_cdc->tx_ff, p_cdc->tx_ff_buf, TU_ARRAY_SIZE(p_cdc->tx_ff_buf), 1, false);
+    tu_fifo_config(&p_cdc->tx_ff, p_cdc->tx_ff_buf, TU_ARRAY_SIZE(p_cdc->tx_ff_buf), 1, true);
 
 #if CFG_FIFO_MUTEX
     tu_fifo_config_mutex(&p_cdc->rx_ff, osal_mutex_create(&p_cdc->rx_ff_mutex));
@@ -355,6 +355,9 @@ bool cdcd_control_request(uint8_t rhport, tusb_control_request_t const * request
 
       p_cdc->line_state = (uint8_t) request->wValue;
 
+      // Disable fifo overwriting if DTR bit is set
+      p_cdc->tx_ff.overwritable = dtr ? false : true;
+
       TU_LOG2("  Set Control Line State: DTR = %d, RTS = %d\r\n", dtr, rts);
 
       tud_control_status(rhport, request);