Texas Instruments MSP50C6xx manual File init.asm, Applications6-5

Initializing the MSP50C6xx

6.2.1File init.asm

;****************************************************************

;INIT.ASM

;Revision 1.04

;Modified from revision 1.03: if not CRO, we check port 0x2F

;	to distinguish between P and
;	C parts.
;

;Turn off TIMER 2 rather than leave it running.

;Modified to cope with 6 bit trim value. Top 5 bits go to bits

;15–11 in ClkSpdCtrl, LSB of trim goes to bit 9 in ClkSpdCtrl.

;A fairly basic but compact initialization routine for the 614.

;This sets the 614 to run at 8 MHz, 10 bit DAC at 8 kHz.

;

;Geoff Martindale, BP

;May 2000 ;****************************************************************

;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

;!!!!!!!!!!!!!!!!!!!!!! WARNING !!!!!!!!!!!!!!!!!!!!!!!!!!!

;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

;! FOR RESISTOR TRIM USERS:

;! DO NOT WRITE TO PORT G PRIOR TO READING THE RTRIM VALUE! ;! THIS PRESERVES THE ZERO VALUE AT PORT 0x2F WHEN READING THE ;! TRIM VALUE (should be zero if P part, should be non–zero if ;! C part). ;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

;!!!!!!!!!!!!!!!!!!!!!! WARNING !!!!!!!!!!!!!!!!!!!!!!!!!!!

;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

;****************************************************************

;Start off by clearing all the RAM (and tags) and then zero

;every register. The status register (STAT) must be cleared

;immediately upon power up. ;**************************************************************** init614

zac a0	;clear a0
mov *0x001,a0		;clear second RAM location, leave first for C––
mov STAT,*0x001		;clear status register
mov STR,32–2		;set string register to loop 32 times
zacs	a0	;clear all accumulators
out IFR,a0		;clear pending interrupts
out IntGenCtrl,a0		;clear all interrupt mask bits, disable timers
mov r0,0x000		;point to beginning of RAM
mov r4,RAM_SIZE – 2		;do a loop RAM_SIZE times
BEGLOOP
rtag	*r0	;reset tag
mov *r0++,a0		;clear the RAM
ENDLOOP
mov STR,0		;clear string register

Applications6-5