This library lets you control the addressable RGB LED strips from Pololu Robotics. Forked to add selectable colour order (Support RGB or GRB Leds)
Fork of PololuLedStrip by
led_strip_write_color.s@21:87fd6273e0ff, 2013-11-26 (annotated)
- Committer:
- DavidEGrayson
- Date:
- Tue Nov 26 23:05:08 2013 +0000
- Revision:
- 21:87fd6273e0ff
- Parent:
- 20:656bbcb64e3b
- Child:
- 22:5368af3ff07d
fixed a comment
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
DavidEGrayson | 0:06475317f283 | 1 | AREA asm_func, CODE, READONLY |
DavidEGrayson | 0:06475317f283 | 2 | EXPORT led_strip_write_color |
DavidEGrayson | 6:9d0530b7dae2 | 3 | IMPORT led_strip_write_delays |
DavidEGrayson | 0:06475317f283 | 4 | |
DavidEGrayson | 7:9a088f042ee0 | 5 | MACRO |
DavidEGrayson | 7:9a088f042ee0 | 6 | delay $id |
DavidEGrayson | 7:9a088f042ee0 | 7 | ldr r5, =led_strip_write_delays |
DavidEGrayson | 7:9a088f042ee0 | 8 | ldrb r5, [r5, $id] |
DavidEGrayson | 7:9a088f042ee0 | 9 | ldr r4, =delay_region_end |
DavidEGrayson | 9:6ffb85d69eaf | 10 | subs r4, r4, r5 |
DavidEGrayson | 7:9a088f042ee0 | 11 | blx r4 |
DavidEGrayson | 7:9a088f042ee0 | 12 | MEND |
DavidEGrayson | 7:9a088f042ee0 | 13 | |
DavidEGrayson | 0:06475317f283 | 14 | led_strip_write_color |
DavidEGrayson | 5:690fdfb595de | 15 | ; Register usage: |
DavidEGrayson | 5:690fdfb595de | 16 | ; These are the first 4 arguments to the method: |
DavidEGrayson | 5:690fdfb595de | 17 | ; R0: pointer to the color to send |
DavidEGrayson | 5:690fdfb595de | 18 | ; R1: pointer to the register for setting the pin |
DavidEGrayson | 5:690fdfb595de | 19 | ; R2: pointer to the register for clearing the pin |
DavidEGrayson | 5:690fdfb595de | 20 | ; R3: pin mask |
DavidEGrayson | 5:690fdfb595de | 21 | ; Additionally, we use these registers: |
DavidEGrayson | 5:690fdfb595de | 22 | ; R4: temporary register |
DavidEGrayson | 6:9d0530b7dae2 | 23 | ; R5: temporary register |
DavidEGrayson | 20:656bbcb64e3b | 24 | ; R6: shift register that holds the 24-bit color |
DavidEGrayson | 5:690fdfb595de | 25 | ; R7: the number of bits we still need to send |
DavidEGrayson | 5:690fdfb595de | 26 | ; R13: Link Register, holds return addresses. |
DavidEGrayson | 7:9a088f042ee0 | 27 | |
DavidEGrayson | 9:6ffb85d69eaf | 28 | ; Push those registers so we can restore them later. |
DavidEGrayson | 11:e00ba70ac54c | 29 | push {r4, r5, r6, r7, lr} |
DavidEGrayson | 10:f1bb84b97788 | 30 | |
DavidEGrayson | 20:656bbcb64e3b | 31 | ldrb r6, [r0, #1] ; Load green. |
DavidEGrayson | 20:656bbcb64e3b | 32 | lsls r6, r6, #24 ; Put green in MSB of r6. |
DavidEGrayson | 9:6ffb85d69eaf | 33 | ldrb r4, [r0, #0] ; Load red. |
DavidEGrayson | 9:6ffb85d69eaf | 34 | lsls r4, r4, #16 |
DavidEGrayson | 20:656bbcb64e3b | 35 | orrs r6, r6, r4 ; Put red in r6. |
DavidEGrayson | 9:6ffb85d69eaf | 36 | ldrb r4, [r0, #2] ; Load blue. |
DavidEGrayson | 9:6ffb85d69eaf | 37 | lsls r4, r4, #8 |
DavidEGrayson | 21:87fd6273e0ff | 38 | orrs r6, r6, r4 ; Put blue in r6. |
DavidEGrayson | 9:6ffb85d69eaf | 39 | |
DavidEGrayson | 21:87fd6273e0ff | 40 | ; On the Cortex-M3 we simply did: |
DavidEGrayson | 9:6ffb85d69eaf | 41 | ; ldr r6, [r0] ; Read the color. Now we have: xxBbGgRr |
DavidEGrayson | 9:6ffb85d69eaf | 42 | ; rbit r6, r6 ; Reverse the order of the bits: rRgGbBxx |
DavidEGrayson | 9:6ffb85d69eaf | 43 | ; rev r6, r6 ; Reverse the order of the bytes: xxbBgGrR |
DavidEGrayson | 9:6ffb85d69eaf | 44 | ; and then we used rrxs for shifting to the right through carry. |
DavidEGrayson | 9:6ffb85d69eaf | 45 | |
DavidEGrayson | 9:6ffb85d69eaf | 46 | ldr r7, =24 ; Initialize the loop counter register. |
DavidEGrayson | 0:06475317f283 | 47 | |
DavidEGrayson | 0:06475317f283 | 48 | send_led_strip_bit |
DavidEGrayson | 0:06475317f283 | 49 | str r3, [r1] ; Drive the line high. |
DavidEGrayson | 0:06475317f283 | 50 | |
DavidEGrayson | 19:46d7ab0ba3e7 | 51 | ; It doesn't really matter exactly how long we delay here as long as it is |
DavidEGrayson | 19:46d7ab0ba3e7 | 52 | ; less than 540 microseconds. |
DavidEGrayson | 19:46d7ab0ba3e7 | 53 | nop |
DavidEGrayson | 19:46d7ab0ba3e7 | 54 | nop |
DavidEGrayson | 19:46d7ab0ba3e7 | 55 | nop |
DavidEGrayson | 19:46d7ab0ba3e7 | 56 | nop |
DavidEGrayson | 19:46d7ab0ba3e7 | 57 | nop |
DavidEGrayson | 19:46d7ab0ba3e7 | 58 | nop |
DavidEGrayson | 0:06475317f283 | 59 | |
DavidEGrayson | 9:6ffb85d69eaf | 60 | ldr r4, =0x80000000 |
DavidEGrayson | 9:6ffb85d69eaf | 61 | tst r6, r4 |
DavidEGrayson | 19:46d7ab0ba3e7 | 62 | bne delay0 |
DavidEGrayson | 12:b6df8ac053c8 | 63 | str r3, [r2] ; If the bit to send it 0, drive the line low. |
DavidEGrayson | 19:46d7ab0ba3e7 | 64 | delay0 |
DavidEGrayson | 0:06475317f283 | 65 | |
DavidEGrayson | 19:46d7ab0ba3e7 | 66 | delay #0 |
DavidEGrayson | 0:06475317f283 | 67 | |
DavidEGrayson | 21:87fd6273e0ff | 68 | tst r6, r8 |
DavidEGrayson | 9:6ffb85d69eaf | 69 | ldr r4, =0x80000000 |
DavidEGrayson | 9:6ffb85d69eaf | 70 | tst r6, r4 |
DavidEGrayson | 19:46d7ab0ba3e7 | 71 | beq delay1 |
DavidEGrayson | 12:b6df8ac053c8 | 72 | str r3, [r2] ; If the bit to send is 1, drive the line low. |
DavidEGrayson | 19:46d7ab0ba3e7 | 73 | delay1 |
DavidEGrayson | 0:06475317f283 | 74 | |
DavidEGrayson | 19:46d7ab0ba3e7 | 75 | delay #1 |
DavidEGrayson | 4:d3b60bd43811 | 76 | |
DavidEGrayson | 12:b6df8ac053c8 | 77 | lsls r6, r6, #1 ; Shift color bits. |
DavidEGrayson | 6:9d0530b7dae2 | 78 | subs r7, r7, #1 ; Decrement the loop counter. |
DavidEGrayson | 12:b6df8ac053c8 | 79 | bne send_led_strip_bit ; Send another bit if we have not reached zero. |
DavidEGrayson | 12:b6df8ac053c8 | 80 | pop {r4, r5, r6, r7, pc} ; Otherwise, restore the registers and return. |
DavidEGrayson | 19:46d7ab0ba3e7 | 81 | bx lr; |
DavidEGrayson | 4:d3b60bd43811 | 82 | |
DavidEGrayson | 4:d3b60bd43811 | 83 | delay_region |
DavidEGrayson | 5:690fdfb595de | 84 | ; The following is 128 nops. |
DavidEGrayson | 0:06475317f283 | 85 | nop |
DavidEGrayson | 0:06475317f283 | 86 | nop |
DavidEGrayson | 0:06475317f283 | 87 | nop |
DavidEGrayson | 0:06475317f283 | 88 | nop |
DavidEGrayson | 0:06475317f283 | 89 | nop |
DavidEGrayson | 0:06475317f283 | 90 | nop |
DavidEGrayson | 0:06475317f283 | 91 | nop |
DavidEGrayson | 0:06475317f283 | 92 | nop |
DavidEGrayson | 0:06475317f283 | 93 | nop |
DavidEGrayson | 0:06475317f283 | 94 | nop |
DavidEGrayson | 0:06475317f283 | 95 | nop |
DavidEGrayson | 0:06475317f283 | 96 | nop |
DavidEGrayson | 0:06475317f283 | 97 | nop |
DavidEGrayson | 4:d3b60bd43811 | 98 | nop |
DavidEGrayson | 4:d3b60bd43811 | 99 | nop |
DavidEGrayson | 4:d3b60bd43811 | 100 | nop |
DavidEGrayson | 4:d3b60bd43811 | 101 | |
DavidEGrayson | 0:06475317f283 | 102 | nop |
DavidEGrayson | 0:06475317f283 | 103 | nop |
DavidEGrayson | 0:06475317f283 | 104 | nop |
DavidEGrayson | 0:06475317f283 | 105 | nop |
DavidEGrayson | 0:06475317f283 | 106 | nop |
DavidEGrayson | 0:06475317f283 | 107 | nop |
DavidEGrayson | 0:06475317f283 | 108 | nop |
DavidEGrayson | 0:06475317f283 | 109 | nop |
DavidEGrayson | 0:06475317f283 | 110 | nop |
DavidEGrayson | 0:06475317f283 | 111 | nop |
DavidEGrayson | 0:06475317f283 | 112 | nop |
DavidEGrayson | 0:06475317f283 | 113 | nop |
DavidEGrayson | 0:06475317f283 | 114 | nop |
DavidEGrayson | 0:06475317f283 | 115 | nop |
DavidEGrayson | 0:06475317f283 | 116 | nop |
DavidEGrayson | 0:06475317f283 | 117 | nop |
DavidEGrayson | 4:d3b60bd43811 | 118 | |
DavidEGrayson | 0:06475317f283 | 119 | nop |
DavidEGrayson | 0:06475317f283 | 120 | nop |
DavidEGrayson | 0:06475317f283 | 121 | nop |
DavidEGrayson | 0:06475317f283 | 122 | nop |
DavidEGrayson | 4:d3b60bd43811 | 123 | nop |
DavidEGrayson | 4:d3b60bd43811 | 124 | nop |
DavidEGrayson | 0:06475317f283 | 125 | nop |
DavidEGrayson | 0:06475317f283 | 126 | nop |
DavidEGrayson | 0:06475317f283 | 127 | nop |
DavidEGrayson | 0:06475317f283 | 128 | nop |
DavidEGrayson | 0:06475317f283 | 129 | nop |
DavidEGrayson | 0:06475317f283 | 130 | nop |
DavidEGrayson | 0:06475317f283 | 131 | nop |
DavidEGrayson | 0:06475317f283 | 132 | nop |
DavidEGrayson | 0:06475317f283 | 133 | nop |
DavidEGrayson | 0:06475317f283 | 134 | nop |
DavidEGrayson | 0:06475317f283 | 135 | |
DavidEGrayson | 0:06475317f283 | 136 | nop |
DavidEGrayson | 0:06475317f283 | 137 | nop |
DavidEGrayson | 0:06475317f283 | 138 | nop |
DavidEGrayson | 0:06475317f283 | 139 | nop |
DavidEGrayson | 0:06475317f283 | 140 | nop |
DavidEGrayson | 0:06475317f283 | 141 | nop |
DavidEGrayson | 0:06475317f283 | 142 | nop |
DavidEGrayson | 0:06475317f283 | 143 | nop |
DavidEGrayson | 0:06475317f283 | 144 | nop |
DavidEGrayson | 0:06475317f283 | 145 | nop |
DavidEGrayson | 4:d3b60bd43811 | 146 | nop |
DavidEGrayson | 4:d3b60bd43811 | 147 | nop |
DavidEGrayson | 4:d3b60bd43811 | 148 | nop |
DavidEGrayson | 4:d3b60bd43811 | 149 | nop |
DavidEGrayson | 4:d3b60bd43811 | 150 | nop |
DavidEGrayson | 4:d3b60bd43811 | 151 | nop |
DavidEGrayson | 0:06475317f283 | 152 | |
DavidEGrayson | 0:06475317f283 | 153 | nop |
DavidEGrayson | 0:06475317f283 | 154 | nop |
DavidEGrayson | 0:06475317f283 | 155 | nop |
DavidEGrayson | 0:06475317f283 | 156 | nop |
DavidEGrayson | 0:06475317f283 | 157 | nop |
DavidEGrayson | 0:06475317f283 | 158 | nop |
DavidEGrayson | 0:06475317f283 | 159 | nop |
DavidEGrayson | 0:06475317f283 | 160 | nop |
DavidEGrayson | 0:06475317f283 | 161 | nop |
DavidEGrayson | 0:06475317f283 | 162 | nop |
DavidEGrayson | 4:d3b60bd43811 | 163 | nop |
DavidEGrayson | 4:d3b60bd43811 | 164 | nop |
DavidEGrayson | 4:d3b60bd43811 | 165 | nop |
DavidEGrayson | 4:d3b60bd43811 | 166 | nop |
DavidEGrayson | 4:d3b60bd43811 | 167 | nop |
DavidEGrayson | 4:d3b60bd43811 | 168 | nop |
DavidEGrayson | 0:06475317f283 | 169 | |
DavidEGrayson | 0:06475317f283 | 170 | nop |
DavidEGrayson | 0:06475317f283 | 171 | nop |
DavidEGrayson | 0:06475317f283 | 172 | nop |
DavidEGrayson | 0:06475317f283 | 173 | nop |
DavidEGrayson | 0:06475317f283 | 174 | nop |
DavidEGrayson | 0:06475317f283 | 175 | nop |
DavidEGrayson | 0:06475317f283 | 176 | nop |
DavidEGrayson | 0:06475317f283 | 177 | nop |
DavidEGrayson | 0:06475317f283 | 178 | nop |
DavidEGrayson | 0:06475317f283 | 179 | nop |
DavidEGrayson | 0:06475317f283 | 180 | nop |
DavidEGrayson | 0:06475317f283 | 181 | nop |
DavidEGrayson | 0:06475317f283 | 182 | nop |
DavidEGrayson | 0:06475317f283 | 183 | nop |
DavidEGrayson | 0:06475317f283 | 184 | nop |
DavidEGrayson | 0:06475317f283 | 185 | nop |
DavidEGrayson | 0:06475317f283 | 186 | |
DavidEGrayson | 0:06475317f283 | 187 | nop |
DavidEGrayson | 0:06475317f283 | 188 | nop |
DavidEGrayson | 0:06475317f283 | 189 | nop |
DavidEGrayson | 0:06475317f283 | 190 | nop |
DavidEGrayson | 0:06475317f283 | 191 | nop |
DavidEGrayson | 0:06475317f283 | 192 | nop |
DavidEGrayson | 0:06475317f283 | 193 | nop |
DavidEGrayson | 0:06475317f283 | 194 | nop |
DavidEGrayson | 0:06475317f283 | 195 | nop |
DavidEGrayson | 0:06475317f283 | 196 | nop |
DavidEGrayson | 4:d3b60bd43811 | 197 | nop |
DavidEGrayson | 4:d3b60bd43811 | 198 | nop |
DavidEGrayson | 4:d3b60bd43811 | 199 | nop |
DavidEGrayson | 4:d3b60bd43811 | 200 | nop |
DavidEGrayson | 4:d3b60bd43811 | 201 | nop |
DavidEGrayson | 4:d3b60bd43811 | 202 | nop |
DavidEGrayson | 4:d3b60bd43811 | 203 | |
DavidEGrayson | 0:06475317f283 | 204 | nop |
DavidEGrayson | 0:06475317f283 | 205 | nop |
DavidEGrayson | 0:06475317f283 | 206 | nop |
DavidEGrayson | 0:06475317f283 | 207 | nop |
DavidEGrayson | 0:06475317f283 | 208 | nop |
DavidEGrayson | 0:06475317f283 | 209 | nop |
DavidEGrayson | 4:d3b60bd43811 | 210 | nop |
DavidEGrayson | 4:d3b60bd43811 | 211 | nop |
DavidEGrayson | 4:d3b60bd43811 | 212 | nop |
DavidEGrayson | 4:d3b60bd43811 | 213 | nop |
DavidEGrayson | 4:d3b60bd43811 | 214 | nop |
DavidEGrayson | 4:d3b60bd43811 | 215 | nop |
DavidEGrayson | 4:d3b60bd43811 | 216 | nop |
DavidEGrayson | 4:d3b60bd43811 | 217 | nop |
DavidEGrayson | 4:d3b60bd43811 | 218 | nop |
DavidEGrayson | 4:d3b60bd43811 | 219 | nop |
DavidEGrayson | 5:690fdfb595de | 220 | delay_region_end |
DavidEGrayson | 4:d3b60bd43811 | 221 | bx lr ; return |
DavidEGrayson | 0:06475317f283 | 222 | |
DavidEGrayson | 0:06475317f283 | 223 | END |