1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
/*
* slow_status_flash.s
*
* Copyright © 2018 Thomas White <taw@bitwiz.org.uk>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
@ vim:ft=armv5
.section .text
.global flash_status_led
flash_status_led:
LDR R8, =0x3f200000
LDR R1, [R8, #0x04] @ GPFSEL1
ORR R1, R1, #1<<18 @ GPIO pin 16 is output
BIC R1, R1, #3<<21 @ GPIO pin 17 is input
ORR R1, R1, #1<<24 @ GPIO pin 18 is output
STR R1, [R8, #0x04] @ GPFSEL1
forever:
MRC P15, 0, R0, C0, C0, 5
AND R0, R0, #0x0f
flashred:
MOV R1, #1<<29
STR R1, [R8, #0x1c] @ GPSET0
BL longpause
MOV R1, #1<<29
STR R1, [R8, #0x28] @ GPCLR0
BL longpause
SUBS R0, R0, #1
BNE flashred
BL longpause
BL longpause
BL longpause
B forever
longpause:
MOV R2, #0x3f0000
1:
SUBS R2, R2, #1
BNE 1b
MOV PC, LR
|
