UART - Virtual COM bridge causes a system freeze

embedded_eng_ — Sun, 01 Aug 2021 15:29:17 GMT

Hi,

I changed the lpcxpresso55s16_dev_composite_cdc_msc_bm example to bridge the virtual com with UART (Flexcomm 1).

The UART part is based on interrupts.

UART to virtual COM:

UART init:

#define FLEXCOMM1_PERIPHERAL USART1 #define FLEXCOMM1_CLOCK_SOURCE 12000000UL #define FLEXCOMM1_FLEXCOMM_IRQN FLEXCOMM1_IRQn #define FLEXCOMM1_FLEXCOMM_IRQHANDLER FLEXCOMM1_IRQHandler usart_config_t config; USART_GetDefaultConfig(&config); config.baudRate_Bps = BOARD_DEBUG_UART_BAUDRATE; config.enableTx = true; config.enableRx = true; USART_Init(FLEXCOMM1_PERIPHERAL, &config, FLEXCOMM1_CLOCK_SOURCE); USART_EnableInterrupts(FLEXCOMM1_PERIPHERAL, kUSART_RxLevelInterruptEnable | kUSART_RxErrorInterruptEnable); EnableIRQ(FLEXCOMM1_FLEXCOMM_IRQN);

UART interrupt handler:

void FLEXCOMM1_IRQHandler(void) { uint8_t data; /* If new data arrived. */ if ((kUSART_RxFifoNotEmptyFlag | kUSART_RxError) & USART_GetStatusFlags(FLEXCOMM1_PERIPHERAL)) { data = USART_ReadByte(FLEXCOMM1_PERIPHERAL); send_to_virtual_com(data); } SDK_ISR_EXIT_BARRIER; }

The function that actually send the data to the virtual com:

void send_to_virtual_com(uint8_t byte) { if ((1 == g_deviceComposite->cdcVcom.attach) && (1 == g_deviceComposite->cdcVcom.startTransactions)) { uint8_t *buf = &byte; USB_DeviceCdcAcmSend(g_deviceComposite->cdcVcom.cdcAcmHandle, USB_CDC_VCOM_DIC_BULK_IN_ENDPOINT, buf, 1); g_deviceComposite->cdcVcomRecvSize = 0; g_deviceComposite->cdcVcomSendSize = 0; } }

Virtual COM to UART:

The following code is part of the infinite loop in main function:

if ((1 == g_deviceComposite->cdcVcom.attach) && (1 == g_deviceComposite->cdcVcom.startTransactions)) { /* User Code */ /* endpoint callback length is USB_CANCELLED_TRANSFER_LENGTH (0xFFFFFFFFU) when transfer is canceled */ if ((0 != g_deviceComposite->cdcVcomRecvSize) && (USB_CANCELLED_TRANSFER_LENGTH != g_deviceComposite->cdcVcomRecvSize)) { int32_t i; /* Copy Buffer to Send Buff */ for (i = 0; i < g_deviceComposite->cdcVcomRecvSize; i++) { s_currSendBuf[g_deviceComposite->cdcVcomSendSize++] = s_currRecvBuf[i]; } g_deviceComposite->cdcVcomRecvSize = 0; } if (g_deviceComposite->cdcVcomSendSize) { uint32_t size = g_deviceComposite->cdcVcomSendSize; g_deviceComposite->cdcVcomSendSize = 0; sendToUart(s_currSendBuf); if (error != kStatus_USB_Success) { } } }

The function that actually send the data to the UART:

void sendToUart(uint8_t *buf) { USART_WriteBlocking(FLEXCOMM1_PERIPHERAL, buf, (sizeof(buf) / sizeof(buf[0])) - 1); }

The problem I have is that after ~7000 bytes sent from UART to the virtual COM, the whole system freezes.

Maybe someone can help?

Re: UART - Virtual COM bridge causes a system freeze

embedded_eng_ — Mon, 02 Aug 2021 07:16:30 GMT

I found the problem.

seems that kUSART_RxErrorInterruptEnable flag caused it.

The bridge works fine without the flag.

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UART - Virtual COM bridge causes a system freeze

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