Hi, a question may need your kind help. Just wonder if nRF52840's USB CDC ACM could support multiple instances? For example, would it support CLI as well as an another serial instance like for AT command? If could , how could I get these? Many thanks.
Hi
Yes, the USBD driver uses a modular structure that allows you to instantiate multiple different classes, the only limitation being the number of IN/OUT endpoints supported by the USBD interface.
I made a quick version of the usbd_cdc_acm example in nRF5 SDK v15.3.0 to demonstrate this, setting up two unique CDC instances, and you will find the main file below:
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#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include "nrf.h"
#include "nrf_drv_usbd.h"
#include "nrf_drv_clock.h"
#include "nrf_gpio.h"
#include "nrf_delay.h"
#include "nrf_drv_power.h"
#include "app_error.h"
#include "app_util.h"
#include "app_usbd_core.h"
#include "app_usbd.h"
#include "app_usbd_string_desc.h"
#include "app_usbd_cdc_acm.h"
#include "app_usbd_serial_num.h"
#include "boards.h"
#include "bsp.h"
#include "bsp_cli.h"
#include "nrf_cli.h"
#include "nrf_cli_uart.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
/**
* @brief CLI interface over UART
*/
NRF_CLI_UART_DEF(m_cli_uart_transport, 0, 64, 16);
NRF_CLI_DEF(m_cli_uart,
"uart_cli:~$ ",
&m_cli_uart_transport.transport,
'\r',
4);
/**@file
* @defgroup usbd_cdc_acm_example main.c
* @{
* @ingroup usbd_cdc_acm_example
* @brief USBD CDC ACM example
*
*/
#define LED_USB_RESUME (BSP_BOARD_LED_0)
#define LED_CDC_ACM_OPEN (BSP_BOARD_LED_1)
#define LED_CDC_ACM_RX (BSP_BOARD_LED_2)
#define LED_CDC_ACM_TX (BSP_BOARD_LED_3)
#define BTN_CDC_DATA_SEND 0
#define BTN_CDC_NOTIFY_SEND 1
#define BTN_CDC_DATA_KEY_RELEASE (bsp_event_t)(BSP_EVENT_KEY_LAST + 1)
/**
* @brief Enable power USB detection
*
* Configure if example supports USB port connection
*/
#ifndef USBD_POWER_DETECTION
#define USBD_POWER_DETECTION true
#endif
static void cdc_acm_user_ev_handler(app_usbd_class_inst_t const * p_inst,
app_usbd_cdc_acm_user_event_t event);
static void cdc_acm2_user_ev_handler(app_usbd_class_inst_t const * p_inst,
app_usbd_cdc_acm_user_event_t event);
#define CDC_ACM_COMM_INTERFACE 0
#define CDC_ACM_COMM_EPIN NRF_DRV_USBD_EPIN2
#define CDC_ACM_DATA_INTERFACE 1
#define CDC_ACM_DATA_EPIN NRF_DRV_USBD_EPIN1
#define CDC_ACM_DATA_EPOUT NRF_DRV_USBD_EPOUT1
#define CDC_ACM_COMM2_INTERFACE 2
#define CDC_ACM_COMM2_EPIN NRF_DRV_USBD_EPIN4
#define CDC_ACM_DATA2_INTERFACE 3
#define CDC_ACM_DATA2_EPIN NRF_DRV_USBD_EPIN3
#define CDC_ACM_DATA2_EPOUT NRF_DRV_USBD_EPOUT3
/**
* @brief CDC_ACM class instance
* */
APP_USBD_CDC_ACM_GLOBAL_DEF(m_app_cdc_acm,
cdc_acm_user_ev_handler,
CDC_ACM_COMM_INTERFACE,
CDC_ACM_DATA_INTERFACE,
CDC_ACM_COMM_EPIN,
CDC_ACM_DATA_EPIN,
CDC_ACM_DATA_EPOUT,
APP_USBD_CDC_COMM_PROTOCOL_AT_V250
);
/**
* @brief CDC_ACM class instance
* */
APP_USBD_CDC_ACM_GLOBAL_DEF(m_app_cdc_acm2,
cdc_acm2_user_ev_handler,
CDC_ACM_COMM2_INTERFACE,
CDC_ACM_DATA2_INTERFACE,
CDC_ACM_COMM2_EPIN,
CDC_ACM_DATA2_EPIN,
CDC_ACM_DATA2_EPOUT,
APP_USBD_CDC_COMM_PROTOCOL_AT_V250
);
#define READ_SIZE 1
static char m_rx_buffer[READ_SIZE];
static char m_tx_buffer[NRF_DRV_USBD_EPSIZE];
static bool m_send_flag = 0;
/**
* @brief User event handler @ref app_usbd_cdc_acm_user_ev_handler_t (headphones)
* */
static void cdc_acm_user_ev_handler(app_usbd_class_inst_t const * p_inst,
app_usbd_cdc_acm_user_event_t event)
{
app_usbd_cdc_acm_t const * p_cdc_acm = app_usbd_cdc_acm_class_get(p_inst);
switch (event)
{
case APP_USBD_CDC_ACM_USER_EVT_PORT_OPEN:
{
bsp_board_led_on(LED_CDC_ACM_OPEN);
/*Setup first transfer*/
ret_code_t ret = app_usbd_cdc_acm_read(&m_app_cdc_acm,
m_rx_buffer,
READ_SIZE);
UNUSED_VARIABLE(ret);
break;
}
case APP_USBD_CDC_ACM_USER_EVT_PORT_CLOSE:
bsp_board_led_off(LED_CDC_ACM_OPEN);
break;
case APP_USBD_CDC_ACM_USER_EVT_TX_DONE:
bsp_board_led_invert(LED_CDC_ACM_TX);
break;
case APP_USBD_CDC_ACM_USER_EVT_RX_DONE:
{
ret_code_t ret;
NRF_LOG_INFO("Bytes waiting: %d", app_usbd_cdc_acm_bytes_stored(p_cdc_acm));
do
{
/*Get amount of data transfered*/
size_t size = app_usbd_cdc_acm_rx_size(p_cdc_acm);
NRF_LOG_INFO("RX: size: %lu char: %c", size, m_rx_buffer[0]);
/* Fetch data until internal buffer is empty */
ret = app_usbd_cdc_acm_read(&m_app_cdc_acm,
m_rx_buffer,
READ_SIZE);
} while (ret == NRF_SUCCESS);
bsp_board_led_invert(LED_CDC_ACM_RX);
break;
}
default:
break;
}
}
/**
* @brief User event handler @ref app_usbd_cdc_acm_user_ev_handler_t (headphones)
* */
static void cdc_acm2_user_ev_handler(app_usbd_class_inst_t const * p_inst,
app_usbd_cdc_acm_user_event_t event)
{
app_usbd_cdc_acm_t const * p_cdc_acm = app_usbd_cdc_acm_class_get(p_inst);
switch (event)
{
case APP_USBD_CDC_ACM_USER_EVT_PORT_OPEN:
{
bsp_board_led_on(LED_CDC_ACM_OPEN);
/*Setup first transfer*/
ret_code_t ret = app_usbd_cdc_acm_read(&m_app_cdc_acm2,
m_rx_buffer,
READ_SIZE);
UNUSED_VARIABLE(ret);
break;
}
case APP_USBD_CDC_ACM_USER_EVT_PORT_CLOSE:
bsp_board_led_off(LED_CDC_ACM_OPEN);
break;
case APP_USBD_CDC_ACM_USER_EVT_TX_DONE:
bsp_board_led_invert(LED_CDC_ACM_TX);
break;
case APP_USBD_CDC_ACM_USER_EVT_RX_DONE:
{
ret_code_t ret;
NRF_LOG_INFO("Bytes waiting: %d", app_usbd_cdc_acm_bytes_stored(p_cdc_acm));
do
{
/*Get amount of data transfered*/
size_t size = app_usbd_cdc_acm_rx_size(p_cdc_acm);
NRF_LOG_INFO("RX: size: %lu char: %c", size, m_rx_buffer[0]);
/* Fetch data until internal buffer is empty */
ret = app_usbd_cdc_acm_read(&m_app_cdc_acm2,
m_rx_buffer,
READ_SIZE);
} while (ret == NRF_SUCCESS);
bsp_board_led_invert(LED_CDC_ACM_RX);
break;
}
default:
break;
}
}
static void usbd_user_ev_handler(app_usbd_event_type_t event)
{
switch (event)
{
case APP_USBD_EVT_DRV_SUSPEND:
bsp_board_led_off(LED_USB_RESUME);
break;
case APP_USBD_EVT_DRV_RESUME:
bsp_board_led_on(LED_USB_RESUME);
break;
case APP_USBD_EVT_STARTED:
break;
case APP_USBD_EVT_STOPPED:
app_usbd_disable();
bsp_board_leds_off();
break;
case APP_USBD_EVT_POWER_DETECTED:
NRF_LOG_INFO("USB power detected");
if (!nrf_drv_usbd_is_enabled())
{
app_usbd_enable();
}
break;
case APP_USBD_EVT_POWER_REMOVED:
NRF_LOG_INFO("USB power removed");
app_usbd_stop();
break;
case APP_USBD_EVT_POWER_READY:
NRF_LOG_INFO("USB ready");
app_usbd_start();
break;
default:
break;
}
}
static void bsp_event_callback(bsp_event_t ev)
{
ret_code_t ret;
switch ((unsigned int)ev)
{
case CONCAT_2(BSP_EVENT_KEY_, BTN_CDC_DATA_SEND):
{
m_send_flag = 1;
break;
}
case BTN_CDC_DATA_KEY_RELEASE :
{
m_send_flag = 0;
break;
}
case CONCAT_2(BSP_EVENT_KEY_, BTN_CDC_NOTIFY_SEND):
{
ret = app_usbd_cdc_acm_serial_state_notify(&m_app_cdc_acm,
APP_USBD_CDC_ACM_SERIAL_STATE_BREAK,
false);
UNUSED_VARIABLE(ret);
break;
}
default:
return; // no implementation needed
}
}
static void init_bsp(void)
{
ret_code_t ret;
ret = bsp_init(BSP_INIT_BUTTONS, bsp_event_callback);
APP_ERROR_CHECK(ret);
UNUSED_RETURN_VALUE(bsp_event_to_button_action_assign(BTN_CDC_DATA_SEND,
BSP_BUTTON_ACTION_RELEASE,
BTN_CDC_DATA_KEY_RELEASE));
/* Configure LEDs */
bsp_board_init(BSP_INIT_LEDS);
}
static void init_cli(void)
{
ret_code_t ret;
ret = bsp_cli_init(bsp_event_callback);
APP_ERROR_CHECK(ret);
nrf_drv_uart_config_t uart_config = NRF_DRV_UART_DEFAULT_CONFIG;
uart_config.pseltxd = TX_PIN_NUMBER;
uart_config.pselrxd = RX_PIN_NUMBER;
uart_config.hwfc = NRF_UART_HWFC_DISABLED;
ret = nrf_cli_init(&m_cli_uart, &uart_config, true, true, NRF_LOG_SEVERITY_INFO);
APP_ERROR_CHECK(ret);
ret = nrf_cli_start(&m_cli_uart);
APP_ERROR_CHECK(ret);
}
int main(void)
{
ret_code_t ret;
static const app_usbd_config_t usbd_config = {
.ev_state_proc = usbd_user_ev_handler
};
ret = NRF_LOG_INIT(NULL);
APP_ERROR_CHECK(ret);
ret = nrf_drv_clock_init();
APP_ERROR_CHECK(ret);
nrf_drv_clock_lfclk_request(NULL);
while(!nrf_drv_clock_lfclk_is_running())
{
/* Just waiting */
}
ret = app_timer_init();
APP_ERROR_CHECK(ret);
init_bsp();
init_cli();
app_usbd_serial_num_generate();
ret = app_usbd_init(&usbd_config);
APP_ERROR_CHECK(ret);
NRF_LOG_INFO("USBD CDC ACM example started.");
app_usbd_class_inst_t const * class_cdc_acm = app_usbd_cdc_acm_class_inst_get(&m_app_cdc_acm);
ret = app_usbd_class_append(class_cdc_acm);
APP_ERROR_CHECK(ret);
app_usbd_class_inst_t const * class_cdc_acm2 = app_usbd_cdc_acm_class_inst_get(&m_app_cdc_acm2);
ret = app_usbd_class_append(class_cdc_acm2);
APP_ERROR_CHECK(ret);
if (USBD_POWER_DETECTION)
{
ret = app_usbd_power_events_enable();
APP_ERROR_CHECK(ret);
}
else
{
NRF_LOG_INFO("No USB power detection enabled\r\nStarting USB now");
app_usbd_enable();
app_usbd_start();
}
while (true)
{
while (app_usbd_event_queue_process())
{
/* Nothing to do */
}
if(m_send_flag)
{
static int frame_counter;
size_t size = sprintf(m_tx_buffer, "Hello USB CDC FA demo: %u\r\n", frame_counter);
ret = app_usbd_cdc_acm_write(&m_app_cdc_acm, m_tx_buffer, size);
if (ret == NRF_SUCCESS)
{
++frame_counter;
}
}
nrf_cli_process(&m_cli_uart);
UNUSED_RETURN_VALUE(NRF_LOG_PROCESS());
/* Sleep CPU only if there was no interrupt since last loop processing */
__WFE();
}
}
/** @} */
Best regards
Torbjørn
Torbjörn:
I grabbed your example main file but alas it did not compile out of the box with the default parameters in the "CLI" demo. I added in app_usbd_serial_num.c and bsp_cli.c and removed "while (app_usbd_event_queue_process())" because first the function wasn't being built and then when I turned on APP_USBD_CONFIG_EVENT_QUEUE_ENABLE I got a compile error indicating
#error "Current CLI CDC implementation supports only USB with event queue disabled (see APP_USBD_CONFIG_EVENT_QUEUE_ENABLE)"
so I modded it not to do that call and do nrf_cli_process instead, for each instance. But alas things did not work properly.
Is there any chance you could zip up and attache complete working project? I would like (although don't *need*) to have two virtual comports between my PC and dongle for some debugging I need to do.
Hi Rob
You will find the full example attached:
238013_usbd_cdc_acm_dual_cdc.zip
Hopefully you will have more success with it.
Best regards
Torbjørn
Thank you, good sir.
I will try it today.
That worked quite well. But it confused Windows 7 a lot - W7 could only assign a driver to one of the CDC ports. W10 and Mac OS did fine, though. I wonder if W7 is confused because both are "CDC Test". Any idea how one would label one of them "CDC Data" and the other "CDC Commands"?
That worked quite well. But it confused Windows 7 a lot - W7 could only assign a driver to one of the CDC ports. W10 and Mac OS did fine, though. I wonder if W7 is confused because both are "CDC Test". Any idea how one would label one of them "CDC Data" and the other "CDC Commands"?
Hi Rob
I had a similar question earlier in Devzone, but unfortunately I was unable to find a good way to label the comports.
I have a suspicion it is related to the .inf file in Windows 7, but I haven't been able to confirm it.
"CDC test" is the product string, which you should be able to reference separately from each CDC instance, but we don't have any examples showing how to do this unfortunately (nor have we tested if this would work on Windows 7).
Best regards
Torbjørn
No problem. W7 is something I use less and less. I'm finding Linux to be more useful as a test platform these days.
Thanks for the example - I'll be able to do good things with it!
Hi Rob
Now that MS effectively deprecated W7 it's definitely not a recommended platform ;)
The best of luck with your project 
Best regards
Torbjørn