MicroEJ UART and other GPIO interrupt with STM32F746G-DISCO

Question

I need to know how to use UART interrupt in MicroEJ(when data receive ,do my job) . I dont want use a thread with while(true) (forever loop) to read input stream. we have these functions in C

LLCOMM_UART_callback and LLCOMM_BUFFERED_CONNECTION_dataReceived

//main uart interrupt

void USART6_IRQHandler(void)
{
    LLCOMM_UART_callback(&LLCOMM_UARTs[UART6_INDEX]);
}
/* Interrupt callback --------------------------------------------------------*/
void LLCOMM_UART_callback(LLCOMM_UART* llcomm)
{
    // retrieve LLCOM environment for given comIndex
    LLCOMM_BUFFERED_CONNECTION* env = &llcomm->header;
    UART_HandleTypeDef* handle = &llcomm->hal_uart_handle;

    uint8_t leave = interrupt_enter();

    // check RX
    if (__HAL_UART_GET_IT(handle, UART_IT_RXNE))
    {
        // read data, clear the interrupt and send data to MicroEJ framework
        LLCOMM_BUFFERED_CONNECTION_dataReceived(env, handle->Instance->RDR);
    }
}

but i cant find how to implement these interface to java ?

the 2nd part is how to use input pins interrupt and interface them to java? is there any API for this??

Thanks

There are several libraries for the use of serial ports in java. See: stackoverflow.com/questions/900950/… — B.Letz
Sry, I guess I misread your question. Hope you'll get helpful answers soon. — B.Letz
No pb , do you know to how to use interface(like what we have in java classes) in c to call a java interface? @B.Letz — Biftor

Gaëtan Harel Gaëtan Harel · Accepted Answer · 2019-05-29T12:16:05

Implementing the LLCOM_UART native interface will allow you to use ECOM COMM in Java.

The UART interrupt is handled by the underlying BSP (in C) caching the data received in a buffer until the Java thread is awake to get back the data of the read. So there is no choice between an interrupt handling or a "loop forever", it is:

interrupt handling in C, data read then cached into a buffer
Java thread periodically waking up and checking if there is data in the buffer

Pins configuration and interrupts handling for UART are not done in Java but in C at the BSP level, using the UART in Java only as a Java stream.

You can find an example of use of the Java comm connectors in our GitHub [1].

As for implementing the LL_UART C side you can take a look at how it was done for an existing platform [2]. Inside the archive you will find an implementation of BSP for STM32F7476G-DISCO, this BSP contains a LL_UART implementation (in platformSource\STM32F746GDISCO-846SI-platformSource.zip\STM32F746GDISCO-846SI-3.1.5-bsp\Projects\STM32746G-Discovery\Applications\MicroEJ\src-comm).

For GPIOs a HAL library exists [3].

Gaëtan

[1] https://github.com/MicroEJ/Example-Standalone-Foundation-Libraries/tree/master/com.microej.example.foundation.ecom.reader

[2] http://developer.microej.com/packages/referenceimplementations/846SI/3.1.5/STM32F746GDISCO-846SI-fullPackaging-eval-3.1.5.zip

[3] https://developer.microej.com/javadoc/microej_4.1/foundation/ej/hal/gpio/package-summary.html

MicroEJ UART and other GPIO interrupt with STM32F746G-DISCO

1 Answers