Copying USB vcom example on LPC11u24 - what am I doing wrong?

[matthollands]

New to the forum so hi!

I have developed my own board using an LPC11U24 chip and want to be able to have a USB virtual serial port so that I can communicate with the chip over USB. I have downloaded the LPCOpen libraries and if I build and flash the nxp_lpcxpresso_11u14_usbd_lib_cdc example to the chip then /dev/ttyACM0 appears on my PC and I can open a serial terminal and have my text echoed back.

But I have been trying to copy the code from nxp_lpcxpresso_11u14_usbd_lib_cdc into my own project and I am never able to get /dev/ttyACMx to appear. Specifically vcom_connected() always returns false in my application. I'm really not sure what I am missing!

Here is the code. As you can see, it is largely borrowed from the nxp_lpcxpresso_11u14_usbd_lib_cdc example so I'm not sure what I am missing. This has been doing my head in for weeks!

#include "chip.h"
#include "Pin.h" //my own thing
#include "PinAssignments.h" //my own thing
#include "SevenSegmentDriver.h" //my own thing
#include "Button.h" //my own thing
#include "LED.h" //my own thing
#include "TestFunctions.h" //my own thing
#include "app_usbd_cfg.h" //referencing nxp_lpcxpresso_11u14_usbd_lib_cdc
#include "cdc_vcom.h" //referencing nxp_lpcxpresso_11u14_usbd_lib_cdc
#include "cdc_vcom.c" //referencing nxp_lpcxpresso_11u14_usbd_lib_cdc
#include "cdc_desc.c" //referencing nxp_lpcxpresso_11u14_usbd_lib_cdc
#include <string.h>

//COPIED FROM nxp_lpcxpresso_11u14_usbd_lib_cdc

/*****************************************************************************
* Public types/enumerations/variables
****************************************************************************/

static USBD_HANDLE_T g_hUsb;
static uint8_t g_rxBuff[256];

extern const USBD_HW_API_T hw_api;
extern const USBD_CORE_API_T core_api;
extern const USBD_CDC_API_T cdc_api;
/* Since this example only uses CDC class link functions for that clas only */
static const USBD_API_T g_usbApi = {
&hw_api,
&core_api,
0,
0,
0,
&cdc_api,
0,
0x02221101,
};

const USBD_API_T *g_pUsbApi = &g_usbApi;

/*****************************************************************************
* Private functions
****************************************************************************/

/* Initialize pin and clocks for USB0/USB1 port */
static void usb_pin_clk_init(void)
{
/* enable USB main clock */
Chip_Clock_SetUSBClockSource(SYSCTL_USBCLKSRC_PLLOUT, 1);
/* Enable AHB clock to the USB block and USB RAM. */
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_USB);
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_USBRAM);
/* power UP USB Phy */
Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_USBPAD_PD);
}

/*****************************************************************************
* Public functions
****************************************************************************/

/**
* @brief Handle interrupt from USB0
* @return Nothing
*/
void USB_IRQHandler(void)
{
USBD_API->hw->ISR(g_hUsb);
}

/* Find the address of interface descriptor for given class type. */
USB_INTERFACE_DESCRIPTOR *find_IntfDesc(const uint8_t *pDesc, uint32_t intfClass)
{
USB_COMMON_DESCRIPTOR *pD;
USB_INTERFACE_DESCRIPTOR *pIntfDesc = 0;
uint32_t next_desc_adr;

pD = (USB_COMMON_DESCRIPTOR *) pDesc;
next_desc_adr = (uint32_t) pDesc;

while (pD->bLength) {
/* is it interface descriptor */
if (pD->bDescriptorType == USB_INTERFACE_DESCRIPTOR_TYPE) {

pIntfDesc = (USB_INTERFACE_DESCRIPTOR *) pD;
/* did we find the right interface descriptor */
if (pIntfDesc->bInterfaceClass == intfClass) {
break;
}
}
pIntfDesc = 0;
next_desc_adr = (uint32_t) pD + pD->bLength;
pD = (USB_COMMON_DESCRIPTOR *) next_desc_adr;
}

return pIntfDesc;
}

int main(void) {
USBD_API_INIT_PARAM_T usb_param;
USB_CORE_DESCS_T desc;
ErrorCode_t ret = LPC_OK;
uint32_t prompt = 0, rdCnt = 0;

SystemCoreClockUpdate();

/* Initialize board and chip */
Chip_GPIO_Init(LPC_GPIO);
Chip_IOCON_PinMuxSet(LPC_IOCON, 0, 11, 1); //set red led pin function to IO

/* enable clocks and pinmux */
usb_pin_clk_init();

/* initilize call back structures */
memset((void *) &usb_param, 0, sizeof(USBD_API_INIT_PARAM_T));
usb_param.usb_reg_base = LPC_USB0_BASE;
usb_param.max_num_ep = 3;
usb_param.mem_base = USB_STACK_MEM_BASE;
usb_param.mem_size = USB_STACK_MEM_SIZE;

/* Set the USB descriptors */
desc.device_desc = (uint8_t *) &USB_DeviceDescriptor[0];
desc.string_desc = (uint8_t *) &USB_StringDescriptor[0];
/* Note, to pass USBCV test full-speed only devices should have both
descriptor arrays point to same location and device_qualifier set to 0.
*/
desc.high_speed_desc = (uint8_t *) &USB_FsConfigDescriptor[0];
desc.full_speed_desc = (uint8_t *) &USB_FsConfigDescriptor[0];
desc.device_qualifier = 0;

//LEDS
LED yellowLED(LEDPins[0]);
LED redLED(LEDPins[1]);
yellowLED = 0;
redLED = 1;

/* USB Initialization */
ret = USBD_API->hw->Init(&g_hUsb, &desc, &usb_param);
if (ret == LPC_OK) {
/* Init VCOM interface */
ret = vcom_init(g_hUsb, &desc, &usb_param);
if (ret == LPC_OK) {
/* enable USB interrrupts */
NVIC_EnableIRQ(USB0_IRQn);
/* now connect */
USBD_API->hw->Connect(g_hUsb, 1);
}

}

redLED = 0;

while (1) {
/* Check if host has connected and opened the VCOM port */
//if ((vcom_connected() != 0) && (prompt == 0)) {
// vcom_write("Hello World!!\r\n", 15);
// prompt = 1;
//}
yellowLED = vcom_connected();
/* If VCOM port is opened echo whatever we receive back to host. */
if (1==1 || prompt) {
rdCnt = vcom_bread(&g_rxBuff[0], 256);
if (rdCnt) {
vcom_write(&g_rxBuff[0], rdCnt);
}
}
/* Sleep until next IRQ happens */
__WFI();
}
}

[lpcxpresso_supp]

Despite what jeremyzhou says - you definitely don't want to use the LPCOpen package for LPC11U68 for development with LPC11U24. The LPC11U1x/2x/3x family are very different to the later LPC11U6x family.

Regards,

LPCXpresso Support

[jeremyzhou]

Hi Matt Hollands,

Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.

According to your description, I think the enumeration fail cause the issue, so I've attached a tool to illustrate the details of the enumeration, then you can figure out which step fails.

And I'd also recommend you to refer to the USB demos which are from lpcopen_2_12_lpcxpresso_nxp_lpcxpresso_11u68, these demos are based on the USB ROM drivers and these drivers are available on LPC11U2x, however it's unavailable for the LPC11U1x.

Hope it helps.

Have a great day!

Ping

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