LPC 822 UART RX with DMA : How can I initialize or advance the descriptor?

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LPC 822 UART RX with DMA : How can I initialize or advance the descriptor?

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友妃代渡辺
Contributor I

I am using LPC822.

C: \ nxp \ LPCXpresso_8.2.2_650 \ lpcxpresso \ Examples \ LPCOpen \ lpcopen_3 _ 02 _ lpcxpresso _ nxp _ lpc xpresso _ 824. Zip \ periph _ dma _ uart

As in this example, four descriptors are used, and DMA_UART is performed only on RX by ping-pong operation.

Received data is always 8 bytes of uint, but there are occasional drops.

I improved it by adding delay so that it does not get lost, but when I miss it, I want to discard the data and capture it at the beginning of the next descriptor, how can it be done?

Or how do I initialize the descriptor?

Now 2 bytes of the next 8 bytes are included in the continuation area of the missing data (eg 6 bytes).


For example, suppose that data "01234567" "89 ABCDEF" is continuously received

descriptor 1: 01234589 (I missed "67")
descriptor 2: ABCDEF00

Because it becomes like this, I want to do as follows.

descriptor 1: 012345  (Discard this data)
descriptor 2: 89 ABCDEF

or

descriptor 1: 012345
Discard this data, initialize the descriptor

descriptor 1: 89 ABCDEF
descriptor 2: 00000000


I want to capture like this.


Thank you.

Yukiyo Watanabe.

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kerryzhou
NXP TechSupport
NXP TechSupport

Hi 友妃代 渡辺,

    Today, I test the project which you mentioned.

    That project cr_startup_lpc82x.c g_pfnVectors have the problems, it doesn't add the DMA interrupt, so you need to add the DMA_IRQHandler, handler at first:

extern void (* const g_pfnVectors[])(void);
__attribute__ ((section(".isr_vector")))
void (* const g_pfnVectors[])(void) = {
    // Core Level - CM0plus
    &_vStackTop, // The initial stack pointer
    ResetISR,                               // The reset handler
    NMI_Handler,                            // The NMI handler
    HardFault_Handler,                      // The hard fault handler
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    SVC_Handler,                            // SVCall handler
    0,                                      // Reserved
    0,                                      // Reserved
    PendSV_Handler,                         // The PendSV handler
    SysTick_Handler,                        // The SysTick handler

    // Chip Level - LPC8xx
    SPI0_IRQHandler,                         // SPI0 controller
    SPI1_IRQHandler,                         // SPI1 controller
    0,                                       // Reserved
    UART0_IRQHandler,                        // UART0
    UART1_IRQHandler,                        // UART1
    UART2_IRQHandler,                        // UART2
    0,                                       // Reserved
    0,                                       // Reserved
    I2C_IRQHandler,                          // I2C controller
    SCT_IRQHandler,                          // Smart Counter Timer
    MRT_IRQHandler,                          // Multi-Rate Timer
    CMP_IRQHandler,                          // Comparator
    WDT_IRQHandler,                          // Watchdog
    BOD_IRQHandler,                          // Brown Out Detect
    0,                                       // Reserved
    WKT_IRQHandler,                          // Wakeup timer
    0,                                       // Reserved
    0,                                       // Reserved
    0,                                       // Reserved
    0,                                       // Reserved
     DMA_IRQHandler,                                       // Reserved
    0,                                       // Reserved
    0,                                       // Reserved
    0,                                       // Reserved
    PININT0_IRQHandler,                      // PIO INT0
    PININT1_IRQHandler,                      // PIO INT1
    PININT2_IRQHandler,                      // PIO INT2
    PININT3_IRQHandler,                      // PIO INT3
    PININT4_IRQHandler,                      // PIO INT4
    PININT5_IRQHandler,                      // PIO INT5
    PININT6_IRQHandler,                      // PIO INT6
    PININT7_IRQHandler,                      // PIO INT7
}; /* End of g_pfnVectors */
‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

void DMA_IRQHandler(void) ALIAS(IntDefaultHandler);

Actually, it't better to refer to the following vector table add the whole vector tables.

extern void (* const g_pfnVectors[])(void);
__attribute__ ((used,section(".isr_vector")))
void (* const g_pfnVectors[])(void) = {
    // Core Level - CM0plus
    &_vStackTop, // The initial stack pointer
    ResetISR,                               // The reset handler
    NMI_Handler,                            // The NMI handler
    HardFault_Handler,                      // The hard fault handler
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    __valid_user_code_checksum,             // LPC MCU Checksum
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    SVC_Handler,                            // SVCall handler
    0,                                      // Reserved
    0,                                      // Reserved
    PendSV_Handler,                         // The PendSV handler
    SysTick_Handler,                        // The SysTick handler

    // Chip Level - LPC82x
    SPI0_IRQHandler,                         // SPI0 controller
    SPI1_IRQHandler,                         // SPI1 controller
    0,                                       // Reserved
    UART0_IRQHandler,                        // UART0
    UART1_IRQHandler,                        // UART1
    UART2_IRQHandler,                        // UART2
    0,                                       // Reserved
    I2C1_IRQHandler,                         // I2C1 controller
    I2C0_IRQHandler,                         // I2C0 controller
    SCT_IRQHandler,                          // Smart Counter Timer
    MRT_IRQHandler,                          // Multi-Rate Timer
    CMP_IRQHandler,                          // Comparator
    WDT_IRQHandler,                          // Watchdog
    BOD_IRQHandler,                          // Brown Out Detect
    FLASH_IRQHandler,                        // Flash Interrupt
    WKT_IRQHandler,                          // Wakeup timer
    ADC_SEQA_IRQHandler,                     // ADC sequence A completion
    ADC_SEQB_IRQHandler,                     // ADC sequence B completion
    ADC_THCMP_IRQHandler,                    // ADC threshold compare
    ADC_OVR_IRQHandler,                      // ADC overrun
    DMA_IRQHandler,                          // DMA
    I2C2_IRQHandler,                         // I2C2 controller
    I2C3_IRQHandler,                         // I2C3 controller
    0,                                       // Reserved
    PININT0_IRQHandler,                      // PIO INT0
    PININT1_IRQHandler,                      // PIO INT1
    PININT2_IRQHandler,                      // PIO INT2
    PININT3_IRQHandler,                      // PIO INT3
    PININT4_IRQHandler,                      // PIO INT4
    PININT5_IRQHandler,                      // PIO INT5
    PININT6_IRQHandler,                      // PIO INT6
    PININT7_IRQHandler,                      // PIO INT7
}; /* End of g_pfnVectors */‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Then build the periph_dma_uart project and run it again.

This is my test result:

pastedImage_1.png

You can find, after several times send, I can receive the correct data.

Just from the received result, I didn't meet the problem which you mentioned, I didn't add the delay code, just comment the __WFI(); code.

My test board is the LPCXpresso824-MAX board, associated with the TTL-USB tool.

So, do you have the official board, can you also use the official board to reflect the problem? If you also can use the official board to reproduce it, please tell me the reproduce steps, thank you!


Have a great day,
Kerry

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友妃代渡辺
Contributor I

Hi, Kerry


Thank you very much.
I'm sorry for the late reply.

It is "g_pfnVectors" of "cr_startup_lpc82x.c" that you taught, but I have already used the one that was fixed.


In my program, it is judged whether or not the following 1. exists in while (1) {} of int main (void), and 2. It executes the following.

1. Receive "command to send version information" from FPGA every certain period (A few tens of seconds).
2. Send Version information from the LPC822 to the FPGA
3. Receive "command to send voltage data" from FPGA
4. Send "command to send voltage data" by UART to microcomputer of other device 1
5. Receive voltage data from microcomputer of other device 1
6. Send the voltage data of the device 1 from the LPC822 to the FPGA
7. Send "command to send voltage data" by UART to the microcomputer of other device 2
8. Receive voltage data from microcomputer of other device 2
9. Send the voltage data of the device 2 from the LPC822 to the FPGA

(All commands here are uint 8 byte.)

I repeat this flow all the while.
However 3 to 5 days later, the command data of 8 bytes is cut off by several bytes, and the next 8 bytes will be inserted in succession.
(The environment uses the debug mode of LPCXpresso v8.2.2)

Since it takes a long time to test, we want to make it a good flow even if this phenomenon occurs.
I want to discard the lost data and put the next data from the beginning of the next descriptor.

Can not you do something like that?

(I am using the original board.
Since there are peripheral devices, exactly the same environment can not be reproduced using LPCXpresso 824-MAX board, but I will try to test whether to reproduce using LPCXpresso 824-MAX board. )


Thank you.

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