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//******************************************************************************
// MSP430x24x Demo - Reset on Invalid Address fetch, Toggle P1.0
//
// Description: This program demonstrates how a reset is executed if the CPU
// tries to fetch instructions from within the module register memory address
// range (0x0000 --0x01FF) or from within unused address ranges. Toggle P1.0
// by xor'ing P1.0 inside of a software loop that ends with TAR loaded with
// 3FFFh - op-code for "jmp $". This simulates a code error. The MSP430F229
// will force a reset because it will not allow a fetch from within the address
// range of the peripheral memory, as is seen by return to the mainloop and
// LED flash.
// ACLK = n/a, MCLK = SMCLK = default DCO ~1.045Mhz
//
// MSP430F249
// -----------------
// /|\| XIN|-
// | | |
// --|RST XOUT|-
// | |
// | P1.0|-->LED
//
// B. Nisarga
// Texas Instruments Inc.
// September 2007
// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.42A
//******************************************************************************
#include "msp430x24x.h"
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
P1DIR |= 0x01; // Set P1.0 to output direction
TAR = 0x3FFF; // Valid opcode (for "jmp $")
for (;;)
{
volatile unsigned int i;
P1OUT ^= 0x01; // Toggle P1.0 using exclusive-OR
i = 50000; // Delay
do (i--);
while (i != 0);
// C code to directly call an address location
((void (*)())0x170)(); // Invalid fetch ("call #0170h")
/* 0x170 is address of TAR register and is within the module register memory
address range (0x0000 --0x01FF) */
} // ** Should never get here **
}
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