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Rockbox mail archiveSubject: Re: Baud rate calculationsRe: Baud rate calculations
From: Paul Suade <paul.suade_at_laposte.net>
Date: Mon, 10 Dec 2001 12:02:35 +0100 GOT IT ! setup_sci1 (int baudrate /* r4 */) : 0x000047A8: mov r4,r5 ; r5 = r4 0x000047AA: mov.l _at_(0x078,pc),r4 ; 0x00004820 (0x00B71B00 --> 12000000 !) ... 0x000047B8: mov #0x00,r6 ; r6 = 0 0x000047BA: mov.w r1,_at_r3 ; PBCR1 &= 0xff0f; |= 0xa0 0x000047BC: shll2 r5 0x000047BE: mov.b r6,_at_r8 ; SCR1 = 0; 0x000047C0: add r5,r5 0x000047C2: mov.l _at_(0x06C,pc),r1 ; 0x0000482C (0x05FFFEC8) 0x000047C4: shll2 r5 ; r5 = r5*32 --> r5 = baudrate *32 ! 0x000047C6: mov.b r6,_at_r1 0x000047C8: jsr _at_r7 ; r0 = r4/r5 0x000047CA: nop 0x000047CC: mov r0,r7 ; r7 = 12000000 / (baudrate*32) ! 0x000047CE: mov r7,r1 0x000047D0: add #0xFF,r1 ; r1 = (12000000 / (baudrate*32))-1 ! 0x000047D2: mov.l _at_(0x060,pc),r0 ; 0x00004830 (0x05FFFEC9) BRR1 0x000047D4: mov.b r1,_at_r0 ; BRR1 = (12000000 / (baudrate*32))-1 ! ... ----- Original Message ----- From: Björn Stenberg <bjorn_at_haxx.se> To: Jukebox development <jukebox_at_cool.haxx.se> Sent: Monday, December 10, 2001 10:45 AM Subject: RE: Baud rate calculations > Nielsen Linus (ext) wrote: > > > No it doesn't set it to 255. The 0xff Björn is referring to > > is a subtraction (using add #0xff). The BRR value is dynamically > > calculated. > > Ah, yes! So I was right, I did sleep too little. :-) > > Well spotted. > > /Björn Received on 2001-12-10 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |