DK-TM4C123g OTG USB_Dev_Serial

Hello Thomas,

If the device is showing up as a unknown device then most probably the device descriptor is faulty. Is the project a hand written project or is it derived from one of the existing DK-TM4C123 project? Please do the share the code.

Regards
Amit

Hi Thomas,
The USB example uses an interrupt vector routine to determine the OTG attached peripheral modes (device/host). That interrupt vector must be added to statup_ccs.c. or the Windows CDM device driver will not receive the descriptor as Amit pointed out.

Thanks for the replies.

I've have made some progress. I added the following lines of code to the example per the "usb_dev_serial example, change UART module not work" forum thread.

ROM_GPIOPinConfigure(GPIO_UARTRX);
ROM_GPIOPinConfigure(GPIO_UARTTX);

I also found that there was some conflict on my computer with the drivers that I had installed.

I can now see the USB serial port on my PC. I can also send characters to the serial port on the PC if I use USBBufferWrite in the application. The last issue that I have is that I've been trying to resolve is why I cannot use the UARTCharPut call as opposed the USBBufferWrite. When I call UARTCharPut , nothing is transmitted and the interrupt eventually get disabled

Is there anything else that I would need to change on UART3 to make it behave like UART0 in the example?

Here is the code that I've changed from the DK-TM4C123G example.


// usb_dev_serial.c - Main routines for the USB CDC serial example.
....
//*****************************************************************************
//
// The base address, peripheral ID and interrupt ID of the UART that is to
// be redirected.
//
//*****************************************************************************

//*****************************************************************************
//
// Defines required to redirect UART3 via USB.
//
//*****************************************************************************
#define USB_UART_BASE UART3_BASE // UART0_BASE
#define USB_UART_PERIPH SYSCTL_PERIPH_UART3 // SYSCTL_PERIPH_UART0
#define USB_UART_INT INT_UART3 // INT_UART0

....
//*****************************************************************************
//
// GPIO peripherals and pins muxed with the redirected UART. These will depend
// upon the IC in use and the UART selected in USB_UART_BASE. Be careful that
// these settings all agree with the hardware you are using.
//
//*****************************************************************************

//*****************************************************************************
//
// Defines required to redirect UART0 via USB.
//
//*****************************************************************************
#define TX_GPIO_BASE GPIO_PORTC_BASE
#define TX_GPIO_PERIPH SYSCTL_PERIPH_GPIOC
#define TX_GPIO_PIN GPIO_PIN_7
#define GPIO_UARTTX GPIO_PC7_U3TX

#define RX_GPIO_BASE GPIO_PORTC_BASE
#define RX_GPIO_PERIPH SYSCTL_PERIPH_GPIOC
#define RX_GPIO_PIN GPIO_PIN_7
#define GPIO_UARTRX GPIO_PC6_U3RX

....
//*****************************************************************************
//
// This is the main application entry function.
//
//*****************************************************************************
int
main(void)
{
uint32_t ui32TxCount;
uint32_t ui32RxCount;
tRectangle sRect;
char pcBuffer[16];
uint32_t ui32Fullness;
const char message[] = "Hello World!";
size_t messageLength;
uint8_t messageIndex = 0;

messageLength = strlen(message);
//
// Enable lazy stacking for interrupt handlers. This allows floating-point
// instructions to be used within interrupt handlers, but at the expense of
// extra stack usage.
//
ROM_FPULazyStackingEnable();

//
// Set the clocking to run from the PLL at 50MHz
//
ROM_SysCtlClockSet(SYSCTL_SYSDIV_4 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);

//
// Configure the required pins for USB operation.
//
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

/*
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOG);
ROM_GPIOPinConfigure(GPIO_PG4_USB0EPEN);
ROM_GPIOPinTypeUSBDigital(GPIO_PORTG_BASE, GPIO_PIN_4);
*/

ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOL);
ROM_GPIOPinTypeUSBAnalog(GPIO_PORTL_BASE, GPIO_PIN_6 | GPIO_PIN_7);
ROM_GPIOPinTypeUSBAnalog(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);

...

//
// Enable the UART that we will be redirecting.
//
ROM_SysCtlPeripheralEnable(USB_UART_PERIPH);

//
// Enable and configure the UART RX and TX pins
//
ROM_SysCtlPeripheralEnable(TX_GPIO_PERIPH);
ROM_SysCtlPeripheralEnable(RX_GPIO_PERIPH);

ROM_GPIOPinConfigure(GPIO_UARTRX);
ROM_GPIOPinConfigure(GPIO_UARTTX);

ROM_GPIOPinTypeUART(TX_GPIO_BASE, TX_GPIO_PIN);
ROM_GPIOPinTypeUART(RX_GPIO_BASE, RX_GPIO_PIN);

...
//
// Main application loop.
//
while(1)
{

if (g_bUSBConfigured== true)
{
// USBBufferWrite((tUSBBuffer *)&g_sTxBuffer, (uint8_t *)message, messageLength);
if (messageIndex == (messageLength-1))
{
messageIndex = 0;
}
UARTCharPut(USB_UART_BASE, message[messageIndex++]);
}
....
}
}

Hello Thomas,

How is UART3 connected to the PC Serial Console. Is there a USB2UART Converter? UART0 is connected to the PC via the ICDI chip.

Regards
Amit