[En-Nut-Discussion] Writting a new UART device -- I solved the problem , very weird

[Avex]

Hi Harald, 

I solved the problem I mentioned before.
I modified the file ifstream.h, however, I still dont know WHY ?

The code I modified :

struct _IFSTREAM {
    int  (*if_input)(NUTDEVICE *);  
    int  (*if_output)(NUTDEVICE *);
    int  (*if_flush)(NUTDEVICE *);  
    volatile u_char if_rx_idx;      
    u_char if_rd_idx;               
    volatile u_char if_tx_idx;   
    u_char if_wr_idx;               
    volatile u_char if_tx_act;    
    u_char if_last_eol;             
    u_char if_rx_buf[64];         <-- I changed the number from 256 to 64
    u_char if_tx_buf[256];       <-- To change this digit made the same problem
};

Would you kindly to tell me why ?  :  )

Avex

> Hi Harald Kipp ,
> 
> I am writting a 4-port driver using st16c554 chip on ethernut 
> platform. I refer to uartavr.c & uarts.c and wrote a program
> following the format like these 2 files.  However, I found, I 
> can't open 4 ports at the same time. To describe it clearly, I
> couldn't open more than 2 ports concurrently. 2 ports is the 
> limitation which I can open at the same time.To open the 
> ports of uart one by one , the operation is correct. However,
>  if I open it more than 2, it means opening 3 ports concurrently, 
> it went wrong. 
> 
> I trace it and I found the problem is at 
> NutHeapAllocClear(sizeof(IFSTREAM));  , shown as follow.
> 
> int UartStInit(NUTDEVICE *dev)
> {
>     volatile IFSTREAM *ifs;
>     volatile UARTSTDCB *dcb;
>     volatile u_char lcr_byte  = 0;
>      volatile u_char fifo_byte = 0;
>      volatile u_char *base;    // reference: dev\eth0rtl.c
> 
>     // Check for valid device.
>     if (dev->dev_type != IFTYP_STREAM)
>         return -1;
> 
> //  #define COMA 0x8000 , int0
> //  #define COMB 0x8008 , int1
> //  #define COMC 0x8010 , int2
> //  #define COMD 0x8018 , int3
>     base = (u_char *)(dev->dev_base); // reference: dev\eth0rtl.c
> 
>     // Initialize interface control block.
>     if (dev->dev_icb == 0)  
>         // Problem : If  I alloc more then 2 times, the data which ports send out will
>         // not be correct 
>         dev->dev_icb = NutHeapAllocClear(sizeof(IFSTREAM));    <-- this line, The Problems
> 
>     ifs = dev->dev_icb;
>     ifs->if_input  = UartStInput;
>     ifs->if_output = UartStOutput;
>     ifs->if_flush  = UartStFlush;
>     // Initialize driver control block.
> .................................................................
> 
>     return 0;
> }


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