I am sure the might help, if the ISR was called in the first place.
But it isn't.
Also, according to the user manual I have,, it states that only U0IIR
must be accessed to clear the IRQ (for TXRE anyways).
--Peter
--- In lpc2000@yahoogroups.com, "Pete" <peterbrown_abroad@y...> wrote:
>
> In an interrupt service routine:
> in order to exit it properly you must, Clear the interrupt flag that
> triggered it (write a 1 to the flag?) eg:
> U0IIR = 0x0000000A; //Clear the interrupt register
>
> anyway, most importantly you also need to write to teh vector
> address register:
> eg:
> VICVectAddr = 0x00000000;//Dummy write to signal end of interrupt
>
> failure to do these will lead to continuous interrupts.....
>
>
> Does this help???
>
> rgds
> pete
>
>
> --- In lpc2000@yahoogroups.com, "peterburdine" <lordofdawn@h...>
> wrote:
> >
> > I think I may be missing something stupid, but can anyone help me?
> > I am tring to write to UART0, but it doesn't seem to work. I am
> > trying to write a software buffer to help out the one byte hardware
> > buffer. Specifically I am using the LPC 2294. Below is my code.
> >
> > I am using the Keil toolset (compiler/debugger/simulator). The
> code
> > works perfectly fine when running it on the simulator, but when I
> try
> > to run it on the chip, I will only get "ho" instead of "hello". I
> put
> > some break points in it when using JTAG to debug, but the ISR is
> never
> > called when running on the real hardware, it is called on the
> > simulator. Also, when I debug on JTAG I never se the THRE or TEMT
> > clear. Can you see anything obviously wrong? I think I put in
> > everything that you need to compile it.
> >
> > #include <stdio.h>
> > #define TX_BUFFER_LENGTH 64
> > #define UART0_THRE (U0LSR & 0x20)
> > #define PINSEL0_00_TxD (0x01)
> > #define PINSEL0_01_GPIO (0x00 << 2)
> > #define U0RBR (*((volatile unsigned char *) 0xE000C000))
> > #define U0THR (*((volatile unsigned char *) 0xE000C000))
> > #define U0IER (*((volatile unsigned char *) 0xE000C004))
> > #define U0IIR (*((volatile unsigned char *) 0xE000C008))
> > #define U0FCR (*((volatile unsigned char *) 0xE000C008))
> > #define U0LCR (*((volatile unsigned char *) 0xE000C00C))
> > #define U0MCR (*((volatile unsigned char *) 0xE000C010))
> > #define U0LSR (*((volatile unsigned char *) 0xE000C014))
> > #define U0MSR (*((volatile unsigned char *) 0xE000C018))
> > #define U0SCR (*((volatile unsigned char *) 0xE000C01C))
> > #define U0DLL (*((volatile unsigned char *) 0xE000C000))
> > #define U0DLM (*((volatile unsigned char *) 0xE000C004))
> > #define VICVectAddr6 (*((volatile unsigned long *) 0xFFFFF118))
> > #define VICVectCntl6 (*((volatile unsigned long *) 0xFFFFF218))
> > #define VICIntSelect (*((volatile unsigned long *) 0xFFFFF00C))
> > #define VICIntEnable (*((volatile unsigned long *) 0xFFFFF010))
> > #define VICIntEnClr (*((volatile unsigned long *) 0xFFFFF014))
> > static Uint16 txBytes = 0;
> > static Uint16 txRdPos = 0;
> > static Uint16 txWrPos = 0;
> > static Uint16 txBuffer[TX_BUFFER_LENGTH];
> >
> > void uart0_config (void);
> > void uart0_isr (void);
> > void uart0_sendByte (Uint8);
> > int putchar(int);
> > int main (void);
> >
> > void uart0_config (void) {
> > // Setup UART 0
> > U0LCR = 0x80; // Enable DLAB
> > U0DLL = 0x16; // Setup BGR
> > U0DLM = 0x05; // ~2400 Bit/s @ 50 Mhz
> > U0LCR = 0x03; // Enable UART 0, 8 bits, no parity, 1 stop bit
> >
> > // Reset the FIFOs
> > U0FCR = 0xC7; // RX FIFO trigger level 8 chars, reset tx and
> rx fifo,
> > enable fifos
> >
> > // Setup Interrupts for UART0
> > U0IER = 0x7;
> > VICIntSelect &= 0x0;
> > VICVectCntl6 = 0x20 | 6;
> > VICVectAddr6 = (unsigned long) uart0_isr;
> > VICIntEnable |= (0x1 << 6); // Enable Uart0 Interrupt
> > }
> >
> > void uart0_isr (void) __irq {
> > switch((U0IIR>>1)&0x7) {
> > // THRE
> > case 001:
> > if(txBytes != 0) {
> > U0THR = txBuffer[txRdPos];
> > txRdPos++;
> > txRdPos = (txRdPos ==
> TX_BUFFER_LENGTH)?0:txRdPos;
> > txBytes--;
> > }
> > break;
> > }
> > }
> >
> > void uart0_sendByte(Uint8 byte) {
> > // Wait until there is room in the buffer
> > while(txBytes == TX_BUFFER_LENGTH);
> > VICIntEnClr |= (1 << 6);
> > if(!UART0_THRE) { // Put it in the software buffer
> > txBuffer[txWrPos] = byte;
> > txWrPos++;
> > txWrPos = (txWrPos == TX_BUFFER_LENGTH)?0:txWrPos;
> > txBytes++;
> > }
> > else { // If the chip buffer is empty, put it there
> > U0THR = byte;
> > }
> > VICIntEnable |= (1 << 6);
> > }
> >
> > int putchar(int a) {
> > uart0_sendByte((int)a);
> > }
> >
> > int main (void) {
> > PINSEL0 = PINSEL0_00_TxD | PINSEL0_01_RxD;
> > printf("hello");
> > }Message
Re: Problems w/ UART
2004-10-07 by peterburdine
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