Lpc2000

--- In lpc2000@yahoogroups.com, "peterburdine" <lordofdawn@h...> wrote:
> 
> I know I've asked this question many many times, but I still can't
> figure out what is wrong.  I've tried some of the code on the forums,
> and that seemed to work.  When I cut and paste it into my project it
> no longer seems to work.  I've reduced this to as simple as I can get
> it, can anyone see some thing wrong?
> 
> The main.c there in full, you should just be able to compile it if you
> use Keil's (if you have gcc, it might need a minor modification).  I
> believe that this should send out an infinite number of 'a's, which of
> course it does on the simulator, but not in real life.  When I debug
> it via JTAG in uVision3, I see the THRE interrupt for a short while,
> but then it dissappears, but the ISR is never called (as seen by the
> LED still being on).  Yes I have tested the LED code, it works.
> 
> Hear is some code from my startup.s (I'm using Keil's)
> 
> // Enter Supervisor Mode and set its Stack Pointer
>                	MSR     CPSR_c, #Mode_SVC|I_Bit|F_Bit
>                	MOV     SP, R0
>                	SUB     R0, R0, #SVC_Stack_Size
> 
> 		// Stay in supervisor mode, IRQ and FIQ
> 		MSR 	CPSR_c, #Mode_SVC
> 
> // Enter the C code
>                 LDR     R0,=main
>                 TST     R0,#1       ; Bit-0 set: main is Thumb
>                 LDREQ   LR,=exit?A  ; ARM Mode
>                 LDRNE   LR,=exit?T  ; Thumb Mode
>                 BX      R0
>                 ENDP
> 
> 
> Here is my main.c
> 
> #define		PINSEL0 		(*((volatile unsigned long *) 0xE002C000))
> #define		VICIntSelect  	(*((volatile unsigned long *) 0xFFFFF00C))
> #define		VICIntEnable  	(*((volatile unsigned long *) 0xFFFFF010))
> #define		VICIntEnClr		(*((volatile unsigned long *) 0xFFFFF014))
> #define		VICVectAddr		(*((volatile unsigned long *) 0xFFFFF030))
> #define		VICVectAddr0	(*((volatile unsigned long *) 0xFFFFF100))
> #define		VICVectCntl0	(*((volatile unsigned long *) 0xFFFFF200))
> #define		VICVectAddr1	(*((volatile unsigned long *) 0xFFFFF104))
> #define		VICVectCntl2	(*((volatile unsigned long *) 0xFFFFF204))
> 
> #define		U0THR			(*((volatile unsigned long *) 0xE000C000))
> #define		U0RBR			(*((volatile unsigned long *) 0xE000C000))
> #define		U0DLL			(*((volatile unsigned long *) 0xE000C000))
> #define		U0DLM			(*((volatile unsigned long *) 0xE000C004))
> #define		U0IER			(*((volatile unsigned long *) 0xE000C004))
> #define		U0IIR			(*((volatile unsigned long *) 0xE000C008))
> #define		U0FCR			(*((volatile unsigned long *) 0xE000C008))
> #define		U0LCR			(*((volatile unsigned long *) 0xE000C00C))
> #define		U0LSR			(*((volatile unsigned long *) 0xE000C014))
> #define		U0SCR			(*((volatile unsigned long *) 0xE000C01C))
> 
> #define		IO0PIN		 	(*((volatile unsigned long *) 0xE0028000))
> #define		IO0SET		 	(*((volatile unsigned long *) 0xE0028004))
> #define		IO0DIR		 	(*((volatile unsigned long *) 0xE0028008))
> #define		IO0CLR		 	(*((volatile unsigned long *) 0xE002800C))
> 
> #define LED_PIN				0x00000100
> #define LED_OFF				(IO0SET = LED_PIN)
> #define LED_ON				(IO0CLR = LED_PIN)
> 
> #define 	PCLK			(60000000)
> #define 	UART_BAUD(baud)	((unsigned short)((PCLK / ((baud) * 16.0)) +
> 0.5))
> 
> void main (void);
> void uart_isr (void);
> 
> static int irq_occured = 0;
> 
> void main(void) {
> 	unsigned short uart_divisor;
> 	volatile unsigned char dummy;	
> 	unsigned int x = 0;
> 
> 	IO0DIR = LED_PIN;	/* enable as output */
> 	LED_ON;
> 
> 	PINSEL0 = 0x00000005;
> 
> 	// Setup UART
> 	U0IER = 0x00;
> 	dummy = U0IIR;
> 	dummy = U0IIR;
> 	dummy = U0DLM;
> 
> 	U0LCR = 0x80; // Enable DLAB
> 	uart_divisor = ((unsigned short)((PCLK / ((19200) * 16.0)))+0.5);
> 	U0DLL = uart_divisor&0xff;
> 	U0DLM = 0;
> 	U0LCR &= 0x7F;  // Disable DLAB
> 	U0LCR = 0x03; // Enable DLAB
> 	U0IER = 0x07;
> 
> 	// Setup interrrupts
> 	VICIntSelect = 0x00000000; // No FIQs
> 	VICIntEnable = (0x1 << 6);  // 6 = Uart 0
> 	VICVectCntl0 = 0x20 | 6;
> 	VICVectAddr0 = (unsigned long)uart_isr;
> 
> 	U0THR = '1';
> 	U0THR = '2';
> 	U0THR = '3';
> 	U0THR = '4';
> 	U0THR = '5';
> 	U0THR = '6';
> 
> 	while(1);
> }
> 
> void uart_isr (void) __irq {
> 	volatile char dummy;
> 
> 	LED_OFF;
> 	dummy = U0IIR;
> 	dummy = U0LSR;	
> 	U0THR = 'a';
> 
> 	VICVectAddr = 0;
> }

I also noticed something else.  The last character that was sent was
being corrupted.  If I removed the interrupt code that would not
happen.  I noticed this when trying to add a timer interrupt (which
also works in Keil's simulator but not when I put it on the chip).