Tomás Vega / PololuLedStrip

Forked PololuLedStrip and modified it to work with the KL25Z. Renamed it to Adafruit_NeoPixel.

Fork of PololuLedStrip by David Grayson

led_strip_write_color.s@11:e00ba70ac54c, 2013-03-01 (annotated)

Committer:
DavidEGrayson
Date:
Fri Mar 01 04:16:44 2013 +0000
Revision:
11:e00ba70ac54c
Parent:
10:f1bb84b97788
Child:
12:b6df8ac053c8
Simplified the pushing and popping of LR.

Who changed what in which revision?

UserRevisionLine numberNew 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 8:1578776ceac5 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 9:6ffb85d69eaf 31 ldrb r4, [r0, #0] ; Load red.
DavidEGrayson 9:6ffb85d69eaf 32 lsls r4, r4, #24
DavidEGrayson 9:6ffb85d69eaf 33 mov r6, r4 ; Put red in MSB of r6.
DavidEGrayson 9:6ffb85d69eaf 34 ldrb r4, [r0, #1] ; Load green.
DavidEGrayson 9:6ffb85d69eaf 35 lsls r4, r4, #16
DavidEGrayson 10:f1bb84b97788 36 orrs r6, r6, r4 ; Put green in r6.
DavidEGrayson 9:6ffb85d69eaf 37 ldrb r4, [r0, #2] ; Load blue.
DavidEGrayson 9:6ffb85d69eaf 38 lsls r4, r4, #8
DavidEGrayson 10:f1bb84b97788 39 orrs r6, r6, r4 ; Put blue in MSB of r6.
DavidEGrayson 9:6ffb85d69eaf 40
DavidEGrayson 9:6ffb85d69eaf 41 ; On the Cortex M0 we simply did:
DavidEGrayson 9:6ffb85d69eaf 42 ; ldr r6, [r0] ; Read the color. Now we have: xxBbGgRr
DavidEGrayson 9:6ffb85d69eaf 43 ; rbit r6, r6 ; Reverse the order of the bits: rRgGbBxx
DavidEGrayson 9:6ffb85d69eaf 44 ; rev r6, r6 ; Reverse the order of the bytes: xxbBgGrR
DavidEGrayson 9:6ffb85d69eaf 45 ; and then we used rrxs for shifting to the right through carry.
DavidEGrayson 9:6ffb85d69eaf 46
DavidEGrayson 9:6ffb85d69eaf 47 ldr r7, =24 ; Initialize the loop counter register.
DavidEGrayson 0:06475317f283 48
DavidEGrayson 0:06475317f283 49 send_led_strip_bit
DavidEGrayson 0:06475317f283 50 str r3, [r1] ; Drive the line high.
DavidEGrayson 0:06475317f283 51
DavidEGrayson 7:9a088f042ee0 52 delay #0
DavidEGrayson 0:06475317f283 53
DavidEGrayson 9:6ffb85d69eaf 54 ldr r4, =0x80000000
DavidEGrayson 9:6ffb85d69eaf 55 tst r6, r4
DavidEGrayson 9:6ffb85d69eaf 56 bne delay1
DavidEGrayson 9:6ffb85d69eaf 57 str r3, [r2] ; If the bit to send it 0, drive the line low.
DavidEGrayson 9:6ffb85d69eaf 58 delay1
DavidEGrayson 0:06475317f283 59
DavidEGrayson 7:9a088f042ee0 60 delay #1
DavidEGrayson 0:06475317f283 61
DavidEGrayson 9:6ffb85d69eaf 62 ldr r4, =0x80000000
DavidEGrayson 9:6ffb85d69eaf 63 tst r6, r4
DavidEGrayson 9:6ffb85d69eaf 64 beq delay2
DavidEGrayson 9:6ffb85d69eaf 65 str r3, [r2] ; If the bit to send is 1, drive the line low.
DavidEGrayson 9:6ffb85d69eaf 66 delay2
DavidEGrayson 0:06475317f283 67
DavidEGrayson 7:9a088f042ee0 68 delay #2
DavidEGrayson 4:d3b60bd43811 69
DavidEGrayson 10:f1bb84b97788 70 lsls r6, r6, #1 ; Shift color bits.
DavidEGrayson 6:9d0530b7dae2 71 subs r7, r7, #1 ; Decrement the loop counter.
DavidEGrayson 5:690fdfb595de 72 bne send_led_strip_bit ; Send another bit if we have not reached zero.
DavidEGrayson 4:d3b60bd43811 73
DavidEGrayson 4:d3b60bd43811 74 led_strip_asm_end
DavidEGrayson 11:e00ba70ac54c 75 pop {r4, r5, r6, r7, pc}
DavidEGrayson 4:d3b60bd43811 76
DavidEGrayson 4:d3b60bd43811 77
DavidEGrayson 4:d3b60bd43811 78 delay_region
DavidEGrayson 5:690fdfb595de 79 ; The following is 128 nops.
DavidEGrayson 0:06475317f283 80 nop
DavidEGrayson 0:06475317f283 81 nop
DavidEGrayson 0:06475317f283 82 nop
DavidEGrayson 0:06475317f283 83 nop
DavidEGrayson 0:06475317f283 84 nop
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 4:d3b60bd43811 93 nop
DavidEGrayson 4:d3b60bd43811 94 nop
DavidEGrayson 4:d3b60bd43811 95 nop
DavidEGrayson 4:d3b60bd43811 96
DavidEGrayson 0:06475317f283 97 nop
DavidEGrayson 0:06475317f283 98 nop
DavidEGrayson 0:06475317f283 99 nop
DavidEGrayson 0:06475317f283 100 nop
DavidEGrayson 0:06475317f283 101 nop
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 4:d3b60bd43811 113
DavidEGrayson 0:06475317f283 114 nop
DavidEGrayson 0:06475317f283 115 nop
DavidEGrayson 0:06475317f283 116 nop
DavidEGrayson 0:06475317f283 117 nop
DavidEGrayson 4:d3b60bd43811 118 nop
DavidEGrayson 4:d3b60bd43811 119 nop
DavidEGrayson 0:06475317f283 120 nop
DavidEGrayson 0:06475317f283 121 nop
DavidEGrayson 0:06475317f283 122 nop
DavidEGrayson 0:06475317f283 123 nop
DavidEGrayson 0:06475317f283 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
DavidEGrayson 0:06475317f283 131 nop
DavidEGrayson 0:06475317f283 132 nop
DavidEGrayson 0:06475317f283 133 nop
DavidEGrayson 0:06475317f283 134 nop
DavidEGrayson 0:06475317f283 135 nop
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 4:d3b60bd43811 141 nop
DavidEGrayson 4:d3b60bd43811 142 nop
DavidEGrayson 4:d3b60bd43811 143 nop
DavidEGrayson 4:d3b60bd43811 144 nop
DavidEGrayson 4:d3b60bd43811 145 nop
DavidEGrayson 4:d3b60bd43811 146 nop
DavidEGrayson 0:06475317f283 147
DavidEGrayson 0:06475317f283 148 nop
DavidEGrayson 0:06475317f283 149 nop
DavidEGrayson 0:06475317f283 150 nop
DavidEGrayson 0:06475317f283 151 nop
DavidEGrayson 0:06475317f283 152 nop
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 4:d3b60bd43811 158 nop
DavidEGrayson 4:d3b60bd43811 159 nop
DavidEGrayson 4:d3b60bd43811 160 nop
DavidEGrayson 4:d3b60bd43811 161 nop
DavidEGrayson 4:d3b60bd43811 162 nop
DavidEGrayson 4:d3b60bd43811 163 nop
DavidEGrayson 0:06475317f283 164
DavidEGrayson 0:06475317f283 165 nop
DavidEGrayson 0:06475317f283 166 nop
DavidEGrayson 0:06475317f283 167 nop
DavidEGrayson 0:06475317f283 168 nop
DavidEGrayson 0:06475317f283 169 nop
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
DavidEGrayson 0:06475317f283 182 nop
DavidEGrayson 0:06475317f283 183 nop
DavidEGrayson 0:06475317f283 184 nop
DavidEGrayson 0:06475317f283 185 nop
DavidEGrayson 0:06475317f283 186 nop
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 4:d3b60bd43811 192 nop
DavidEGrayson 4:d3b60bd43811 193 nop
DavidEGrayson 4:d3b60bd43811 194 nop
DavidEGrayson 4:d3b60bd43811 195 nop
DavidEGrayson 4:d3b60bd43811 196 nop
DavidEGrayson 4:d3b60bd43811 197 nop
DavidEGrayson 4:d3b60bd43811 198
DavidEGrayson 0:06475317f283 199 nop
DavidEGrayson 0:06475317f283 200 nop
DavidEGrayson 0:06475317f283 201 nop
DavidEGrayson 0:06475317f283 202 nop
DavidEGrayson 0:06475317f283 203 nop
DavidEGrayson 0:06475317f283 204 nop
DavidEGrayson 4:d3b60bd43811 205 nop
DavidEGrayson 4:d3b60bd43811 206 nop
DavidEGrayson 4:d3b60bd43811 207 nop
DavidEGrayson 4:d3b60bd43811 208 nop
DavidEGrayson 4:d3b60bd43811 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 5:690fdfb595de 215 delay_region_end
DavidEGrayson 4:d3b60bd43811 216 bx lr ; return
DavidEGrayson 0:06475317f283 217
DavidEGrayson 0:06475317f283 218 END