1 ; Various functions: init, (RAM) disk, mmc, timer
3 ; Copyright (C) 2010 Sprite_tm
4 ; Copyright (C) 2010 Leo C.
6 ; This file is part of avrcpm.
8 ; avrcpm is free software: you can redistribute it and/or modify it
9 ; under the terms of the GNU General Public License as published by
10 ; the Free Software Foundation, either version 3 of the License, or
11 ; (at your option) any later version.
13 ; avrcpm is distributed in the hope that it will be useful,
14 ; but WITHOUT ANY WARRANTY; without even the implied warranty of
15 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 ; GNU General Public License for more details.
18 ; You should have received a copy of the GNU General Public License
19 ; along with avrcpm. If not, see <http://www.gnu.org/licenses/>.
24 #define REFR_PRE 8 /* timer prescale factor 1/8 */
25 #define REFR_CS 0x02 /* timer clock select for 1/8 */
26 #define REFR_CNT F_CPU / REFR_RATE / REFR_PRE
31 .db 0xFE,0xFC ; _RAS0 _CAS0
32 .db 0xF8,0xF4 ; _OE _WE
37 ldi temp,low(RAMEND) ; top of memory
38 out SPL,temp ; init stack pointer
39 ldi temp,high(RAMEND) ; top of memory
40 out SPH,temp ; init stack pointer
42 ; - Load some registers with constant values
48 cpi zl,low(regval_tab_e*2)
56 ldi temp,(1<<WDCE) | (1<<WDE)
63 ldi temp,(1<<PUD) ;disable pullups
65 out PORTD,_255 ;all pins high
68 out DDRD,_255 ; all outputs
71 cbi P_RXD-1,RXD ; RXD pin is input
81 ldi temp2,high(ramtop)
89 ; Init clock/timer system
91 ; Init timer 1 as 1 ms system clock tick.
93 ldi temp, low (F_CPU/1000)
94 ldi temp2,high(F_CPU/1000)
97 ldi temp,(1<<ICNC1)|(1<<CS10) ;Noise cancel, fall. edge, Normal Mode, clk/1
100 ori temp,(1<<OCIE1B) ;Enable 1ms int.
107 ;Init timer2. Refresh-call should happen every (8ms/512)=312 cycles.
109 ldi temp,REFR_CNT*2 ; 2 cycles per int
112 ori temp,(1<<WGM21) ;CTC mode
115 ori temp,REFR_CS ;clk/REFR_PRE
118 ori temp, (1<<OCIE2A)
131 .db 13,13,"CPM on an AVR, v"
132 db_version VMAJOR, VMINOR
133 printstring " r" SVN_REVSTR
137 printstring "Testing RAM: fill..."
146 printstring "wait..."
155 printstring "reread..."
159 clr temp3 ;Error counter
163 ; ori temp,0x04 ;simulate error
173 printstring "Addr xx yy "
206 tst temp3 ;any errors?
209 printstring " System halted!"
211 rjmp halted_loop ;keep AVR in an endless loop
226 ;----------------------------------------------------------------------------
230 printstring "Initing mmc..."
232 lcall mgr_init_partitions
236 printstring "No bootable CP/M disk found! Please change MMC/SD-Card."
248 lcall mgr_prnt_parttbl
250 printstring "Partinit done."
252 lcall dsk_inval_hostbuf ;init (de)blocking buffer
254 ; Read first sector of first CP/M partition (ipl)