projects / avrcpm.git / blame
| Commit | Line | Data |
|---|---|---|
| 9c15f366 L |
1 | ; DRAM interface for 2 RAM chips. Supports up to 4 Mbyte of DRAM. |
| 2 | ; This is part of the Z80-CP/M emulator written by Sprite_tm. | |
| 3 | ||
| 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 | ; $Id$ | |
| 22 | ; | |
| 23 | ||
| 24 | .cseg | |
| 25 | ||
| 26 | ; ------------------ DRAM routines ------------- | |
| 27 | ||
| 28 | ;Loads the byte on address xh:xl into temp. | |
| 29 | ;must not alter xh:xl | |
| 30 | ||
| 31 | dram_read: | |
| 32 | cli ; | |
| 33 | out PORTD,xh ;1 | |
| 34 | out PORTC,_RAS0 ;1 | |
| 35 | out PORTD,xl ;1 | |
| 36 | out PORTC,_CAS0 ;1 | |
| 37 | out DDRD,_0 ;1 | |
| 38 | out PORTC,_OE ;1 | |
| 39 | rjmp PC+1 ;2 | |
| 40 | dram_wait DRAM_WAITSTATES ; | |
| 41 | in temp,PIND ;1 | |
| 42 | out PORTC,_255 ;1 | |
| 43 | out DDRD,_255 ;1 | |
| 44 | sei ; | |
| 45 | ret | |
| 46 | ||
| 47 | ||
| 48 | ||
| 49 | ;Writes the byte in temp to xh:xl | |
| 50 | ;must not alter xh:xl | |
| 51 | ||
| 52 | dram_write: | |
| 53 | cli | |
| 54 | out PORTD,xh ;1 | |
| 55 | out PORTC,_RAS0 ;1 | |
| 56 | out PORTD,xl ;1 | |
| 57 | out PORTC,_CAS0 ;1 | |
| 58 | out PORTD,temp ;1 | |
| 59 | out PORTC,_WE ;1 | |
| 60 | out PORTC,_255 ;1 = 7 | |
| 61 | sei | |
| 62 | ret | |
| 63 | ||
| 4675c141 L |
64 | ; ------------------------------------------------------------------- |
| 65 | ||
| 66 | dram_readw_pp: | |
| 67 | rcall dram_read | |
| 68 | adiw x,1 | |
| 69 | push temp | |
| 70 | rcall dram_read | |
| 71 | adiw x,1 | |
| 72 | mov temp2,temp | |
| 73 | pop temp | |
| 74 | ret | |
| 75 | ||
| 76 | dram_read_pp: | |
| 77 | rcall dram_read | |
| 78 | adiw x,1 | |
| 79 | ret | |
| 80 | ||
| 81 | ; ------------------------------------------------------------------- | |
| 82 | ||
| 83 | dram_writew_pp: | |
| 84 | rcall dram_write | |
| 85 | adiw x,1 | |
| 86 | mov temp,temp2 | |
| 87 | dram_write_pp: | |
| 88 | rcall dram_write | |
| 89 | adiw x,1 | |
| 90 | ret | |
| 91 | ||
| 92 | ||
| 93 | ; ------------------------------------------------------------------- | |
| 94 | ; vim:set ts=8 noet nowrap | |
| 9c15f366 | 95 |