USBD on nRF52840 dongle

[Gerry]

Hi,

I modified your USBD BLE UART Example by commenting out the button and LED code to run on a dongle with J-Link debugger soldered on.

I removed the bootloader and set NRF_UICR->REGOUT0 to 3.3V, to ensure proper voltage.

The example runs, all USBD-functions return NRF_SUCCESS when starting up. Also the virtual comport is listed on the PC.

When sending data from a terminal, nothing happens. the cdc_acm_user_ev_handler is never fired.

Is there someting I'm missing?

Working with nRF5_SDK_15.2.0 and debugging with SES.

Best regards

Gerry

[Einar Thorsrud]

Hi Gerry,

It is clear that many things work since the device enumerates correctly on the PC. Can you upload your project here so that I can see what you have modified from the example? I suspect we will find an error there, though I do not have any specific ideas without knowing more.

[Gerry]

Hi Einar

Thanks for your support. I've attached the modified example.

usbd_ble_uart.zip

[Einar Thorsrud]

Hi,

Diffing your code to the example I do not see anything obvious:

Fullscreen main.c.diff Download

diff --git a/examples/peripheral/usbd_ble_uart/main.c b/examples/peripheral/usbd_ble_uart/main.c
index d2c40e9..2b3a6ab 100644
--- a/examples/peripheral/usbd_ble_uart/main.c
+++ b/examples/peripheral/usbd_ble_uart/main.c
@@ -666,22 +666,22 @@ static void cdc_acm_user_ev_handler(app_usbd_class_inst_t const * p_inst,
             ret_code_t ret = app_usbd_cdc_acm_read(&m_app_cdc_acm,
                                                    m_cdc_data_array,
                                                    1);
-            UNUSED_VARIABLE(ret);
-            ret = app_timer_stop(m_blink_cdc);
-            APP_ERROR_CHECK(ret);
-            bsp_board_led_on(LED_CDC_ACM_CONN);
-            NRF_LOG_INFO("CDC ACM port opened");
+//            UNUSED_VARIABLE(ret);
+//            ret = app_timer_stop(m_blink_cdc);
+//            APP_ERROR_CHECK(ret);
+//            bsp_board_led_on(LED_CDC_ACM_CONN);
+//            NRF_LOG_INFO("CDC ACM port opened");
             break;
         }
 
         case APP_USBD_CDC_ACM_USER_EVT_PORT_CLOSE:
-            NRF_LOG_INFO("CDC ACM port closed");
+//            NRF_LOG_INFO("CDC ACM port closed");
             if (m_usb_connected)
             {
-                ret_code_t ret = app_timer_start(m_blink_cdc,
-                                                 APP_TIMER_TICKS(LED_BLINK_INTERVAL),
-                                                 (void *) LED_CDC_ACM_CONN);
-                APP_ERROR_CHECK(ret);
+//                ret_code_t ret = app_timer_start(m_blink_cdc,
+//                                                 APP_TIMER_TICKS(LED_BLINK_INTERVAL),
+//                                                 (void *) LED_CDC_ACM_CONN);
+//                APP_ERROR_CHECK(ret);
             }
             break;
 
@@ -702,9 +702,9 @@ static void cdc_acm_user_ev_handler(app_usbd_class_inst_t const * p_inst,
                 {
                     if (index > 1)
                     {
-                        bsp_board_led_invert(LED_CDC_ACM_RX);
-                        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
-                        NRF_LOG_HEXDUMP_DEBUG(m_cdc_data_array, index);
+//                        bsp_board_led_invert(LED_CDC_ACM_RX);
+//                        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
+//                        NRF_LOG_HEXDUMP_DEBUG(m_cdc_data_array, index);
 
                         do
                         {
@@ -715,20 +715,20 @@ static void cdc_acm_user_ev_handler(app_usbd_class_inst_t const * p_inst,
                                 length += sizeof(ENDLINE_STRING);
                             }
 
-                            ret = ble_nus_data_send(&m_nus,
-                                                    (uint8_t *) m_cdc_data_array,
-                                                    &length,
-                                                    m_conn_handle);
+//                            ret = ble_nus_data_send(&m_nus,
+//                                                    (uint8_t *) m_cdc_data_array,
+//                                                    &length,
+//                                                    m_conn_handle);
 
                             if (ret == NRF_ERROR_NOT_FOUND)
                             {
-                                NRF_LOG_INFO("BLE NUS unavailable, data received: %s", m_cdc_data_array);
+//                                NRF_LOG_INFO("BLE NUS unavailable, data received: %s", m_cdc_data_array);
                                 break;
                             }
 
                             if (ret == NRF_ERROR_RESOURCES)
                             {
-                                NRF_LOG_ERROR("BLE NUS Too many notifications queued.");
+//                                NRF_LOG_ERROR("BLE NUS Too many notifications queued.");
                                 break;
                             }
 
@@ -745,7 +745,7 @@ static void cdc_acm_user_ev_handler(app_usbd_class_inst_t const * p_inst,
 
                 /*Get amount of data transferred*/
                 size_t size = app_usbd_cdc_acm_rx_size(p_cdc_acm);
-                NRF_LOG_DEBUG("RX: size: %lu char: %c", size, m_cdc_data_array[index - 1]);
+//                NRF_LOG_DEBUG("RX: size: %lu char: %c", size, m_cdc_data_array[index - 1]);
 
                 /* Fetch data until internal buffer is empty */
                 ret = app_usbd_cdc_acm_read(&m_app_cdc_acm,
@@ -783,7 +783,7 @@ static void usbd_user_ev_handler(app_usbd_event_type_t event)
             break;
 
         case APP_USBD_EVT_POWER_DETECTED:
-            NRF_LOG_INFO("USB power detected");
+//            NRF_LOG_INFO("USB power detected");
 
             if (!nrf_drv_usbd_is_enabled())
             {
@@ -793,10 +793,10 @@ static void usbd_user_ev_handler(app_usbd_event_type_t event)
 
         case APP_USBD_EVT_POWER_REMOVED:
         {
-            NRF_LOG_INFO("USB power removed");
-            ret_code_t err_code = app_timer_stop(m_blink_cdc);
-            APP_ERROR_CHECK(err_code);
-            bsp_board_led_off(LED_CDC_ACM_CONN);
+//            NRF_LOG_INFO("USB power removed");
+//            ret_code_t err_code = app_timer_stop(m_blink_cdc);
+//            APP_ERROR_CHECK(err_code);
+//            bsp_board_led_off(LED_CDC_ACM_CONN);
             m_usb_connected = false;
             app_usbd_stop();
         }
@@ -804,11 +804,11 @@ static void usbd_user_ev_handler(app_usbd_event_type_t event)
 
         case APP_USBD_EVT_POWER_READY:
         {
-            NRF_LOG_INFO("USB ready");
-            ret_code_t err_code = app_timer_start(m_blink_cdc,
-                                                  APP_TIMER_TICKS(LED_BLINK_INTERVAL),
-                                                  (void *) LED_CDC_ACM_CONN);
-            APP_ERROR_CHECK(err_code);
+//            NRF_LOG_INFO("USB ready");
+//            ret_code_t err_code = app_timer_start(m_blink_cdc,
+//                                                  APP_TIMER_TICKS(LED_BLINK_INTERVAL),
+//                                                  (void *) LED_CDC_ACM_CONN);
+//            APP_ERROR_CHECK(err_code);
             m_usb_connected = true;
             app_usbd_start();
         }
@@ -824,15 +824,24 @@ static void usbd_user_ev_handler(app_usbd_event_type_t event)
 /** @brief Application main function. */
 int main(void)
 {
+    if (NRF_UICR->REGOUT0 != 0xFFFFFFFD) {
+	NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos;
+	while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}
+	NRF_UICR->REGOUT0 = 0xFFFFFFFD; //3.3V
+        while (NRF_NVMC->READY == NVMC_READY_READY_Busy) {}
+	NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos;
+	while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}
+    }
+
     ret_code_t ret;
     static const app_usbd_config_t usbd_config = {
         .ev_state_proc = usbd_user_ev_handler
     };
     // Initialize.
-    log_init();
+    //log_init();
     timers_init();
 
-    buttons_leds_init();
+    //buttons_leds_init();
 
     app_usbd_serial_num_generate();
 

You disable logging and do not use the BSP (for LEDs). Then you add code for setting the REG0 voltage to 3.3 V to compensate for not calling the BSP code that does this. The BSP implementation sets 3.0 V (see gpio_output_voltage_setup() in components\boards\boards.c), but that should not matter.

How have you verified that cdc_acm_user_ev_handler is never fired when it should? Could it be a problem with optimization or similar? What happens if you try to  toggle a GPIO in the event handler?

(One other thing I notice is that the way you check REGOUT0 before setting it, the device would continue to write to it and reset forever if it was for instance set to 3 V initially (last three bits 0x4 which is "100"), since only 1's are converted to 0's when writing to flash). So if you have not performed a full chip erase that might be a problem, as 3 V is used by the firmware it ships with. This does not seem relevant though since it is done at the beginning of main() and it seems the nRF enumerates correctly).

[Gerry]

Hi,

I now replaced the code for 3.0V with gpio_output_voltage_setup() in components\boards\boards.c and made a chip erase ("Erase all" in SES)

I also tried to toggle an LED in cdc_acm_user_ev_handler. This is really never fired.

After some more debugging, I found, that if I connect BLE with the Nordic UART App. and send some characters, I end up in the nus_data_handler. When app_usbd_cdc_acm_write is called there, it returns 8 = NRF_ERROR_INVALID_STATE

        // Send data through CDC ACM
        ret_code_t ret = app_usbd_cdc_acm_write(&m_app_cdc_acm,
                                                m_nus_data_array,
                                                length);
        if(ret != NRF_SUCCESS)
        {
            NRF_LOG_INFO("CDC ACM unavailable, data received: %s", m_nus_data_array);
        }

could it be a problem of the dongle? I have 2 brand new dongles here. Have you ever tried to run this on a nRF52840 dongle?

[Einar Thorsrud]

Hi,

I was not able to reproduce the exact error you describe here. However, I tested now and did get an obvious error when sending data from the PC over the USB-UART (CDC). You have commented out the call to ble_nus_data_send() in the handling of APP_USBD_CDC_ACM_USER_EVT_RX_DONE , but you continue to check the uninitialized ret variable repeatedly. This triggers an error in my test (though it might fail differently or not at all for you, depending on what happens to be in memory).

[Gerry]

Hi,

I changed this, thanks for the input. The behavior is still the same. I now tried with the original (unchanged) example on a nRF52840 DK and I have the exact same issue. When I send some characters to the virtual comport the terminal program gets stuck. Could this be a driver issue? I also tried another USB-port and uninstalled the driver. When I plug in USB, the driver is installed autom. and shows no errors. 

I'm using Windows10 and this terminal program

[Einar Thorsrud]

Hi,

It is expected that you get the same behavior using a DK and a dongle.

Gerry said:

When I send some characters to the virtual comport the terminal program gets stuck. Could this be a driver issue?

I am not sure. Is there a pattern? Always the same number of characters? Or something else?

Gerry said:

I'm using Windows10 and this terminal program

It should not matter, but could you test with PuTTY? 

[Gerry]

Hi,

PuTTY was a good idea. Everything works fine with PuTTY even on the dongle. Sadly, this seems to be the only terminal it's working with. I also have an own PC-application written in c# that works fine with my application on the nRF52840 DK, but not with the USBD BLE UART example.

In the end, I will have to communicate from/to that custom PC-application to the dongle.

Do you have an idea, what could cause this problem? There must be a difference in this virtual com ports right?

[Gerry]

Hi,

I finally found the cause of that problem. DTR of the terminal has to be set, see this post

Thanks for your support anyway.