avrcpm/avr/dram-refresh.asm

   1 ;    DRAM refresh
   2 ;
   3 ;    Copyright (C) 2010 Sprite_tm
   4 ;    Copyright (C) 2010 Leo C.
   5 ;
   6 ;    This file is part of avrcpm.
   7 ;
   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.
  12 ;
  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.
  17 ;
  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/>.
  20 ;
  21 ;    $Id: remainders.asm 108 2010-10-01 09:34:19Z leo $
  22 ;
  23
  24
  25 ; ------------------- DRAM Refresh Interrupt --------------------
  26
  27         .cseg
  28
  29         INTERRUPT OC2Aaddr
  30
  31         sbis    P_RAS,ram_ras   ;2
  32         reti
  33                                 ;       CAS  RAS
  34         cbi     P_CAS,ram_cas   ;2       1|   1|
  35                                 ;        1|   1|
  36         cbi     P_RAS,ram_ras   ;2      |0    1|
  37                                 ;       |0    1|
  38         nop                     ;1      |0   |0
  39 ;       nop                     ;1      |0   |0
  40         sbi     P_RAS,ram_ras   ;2      |0   |0
  41                                 ;       |0   |0
  42         dram_wait DRAM_WAITSTATES-1 ;   |    |
  43 ;       nop                     ;1      |0   |0
  44         cbi     P_RAS,ram_ras   ;2      |0    1|
  45                                 ;       |0    1|
  46         sbi     P_CAS,ram_cas   ;2      |0   |0
  47                                 ;       |0   |0
  48         sbi     P_RAS,ram_ras   ;2       1|  |0
  49                                 ;        1|   1|
  50         reti                    ;4  --> 21 cycles
  51
  52
  53 ; vim:set ts=8 noet nowrap
  54