David Knight / PololuLedStrip

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 David Grayson

led_strip_write_color.s@6:9d0530b7dae2, 2013-03-01 (annotated)

Committer:
DavidEGrayson
Date:
Fri Mar 01 00:31:24 2013 +0000
Revision:
6:9d0530b7dae2
Parent:
5:690fdfb595de
Child:
7:9a088f042ee0
Successfully read the delay amount from a table.

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 0:06475317f283 5 led_strip_write_color
DavidEGrayson 5:690fdfb595de 6 ; Register usage:
DavidEGrayson 5:690fdfb595de 7 ; These are the first 4 arguments to the method:
DavidEGrayson 5:690fdfb595de 8 ; R0: pointer to the color to send
DavidEGrayson 5:690fdfb595de 9 ; R1: pointer to the register for setting the pin
DavidEGrayson 5:690fdfb595de 10 ; R2: pointer to the register for clearing the pin
DavidEGrayson 5:690fdfb595de 11 ; R3: pin mask
DavidEGrayson 5:690fdfb595de 12 ; Additionally, we use these registers:
DavidEGrayson 5:690fdfb595de 13 ; R4: temporary register
DavidEGrayson 6:9d0530b7dae2 14 ; R5: temporary register
DavidEGrayson 5:690fdfb595de 15 ; R7: the number of bits we still need to send
DavidEGrayson 5:690fdfb595de 16 ; R12: shift register that holds the 24-bit color
DavidEGrayson 5:690fdfb595de 17 ; R13: Link Register, holds return addresses.
DavidEGrayson 5:690fdfb595de 18
DavidEGrayson 5:690fdfb595de 19
DavidEGrayson 6:9d0530b7dae2 20 push {r4, r5, r12, r7, lr}
DavidEGrayson 0:06475317f283 21
DavidEGrayson 0:06475317f283 22 ldr r12, [r0] ; Read the next color.
DavidEGrayson 0:06475317f283 23 rbit r12, r12 ; Reverse the order of the bits.
DavidEGrayson 0:06475317f283 24 rev r12, r12 ; Reverse the order of the bytes.
DavidEGrayson 0:06475317f283 25 mov r7, #24 ; Initialize the loop counter register.
DavidEGrayson 0:06475317f283 26
DavidEGrayson 0:06475317f283 27 send_led_strip_bit
DavidEGrayson 0:06475317f283 28 str r3, [r1] ; Drive the line high.
DavidEGrayson 0:06475317f283 29 rrxs r12, r12 ; Rotate right through carry.
DavidEGrayson 0:06475317f283 30
DavidEGrayson 6:9d0530b7dae2 31 ldr r5, =led_strip_write_delays
DavidEGrayson 6:9d0530b7dae2 32 ldrb r5, [r5, #0]
DavidEGrayson 6:9d0530b7dae2 33 lsl r5, r5, #1
DavidEGrayson 5:690fdfb595de 34 ldr r4, =delay_region_end
DavidEGrayson 6:9d0530b7dae2 35 sub r4, r4, r5
DavidEGrayson 5:690fdfb595de 36 blx r4
DavidEGrayson 0:06475317f283 37
DavidEGrayson 0:06475317f283 38 it cc ; If the bit to send it 0...
DavidEGrayson 0:06475317f283 39 strcc r3, [r2] ; Drive the line low.
DavidEGrayson 0:06475317f283 40
DavidEGrayson 5:690fdfb595de 41 ldr r4, =delay_region_end
DavidEGrayson 5:690fdfb595de 42 sub r4, r4, #59*2
DavidEGrayson 5:690fdfb595de 43 blx r4
DavidEGrayson 0:06475317f283 44
DavidEGrayson 0:06475317f283 45 it cs ; If the bit to send is 1...
DavidEGrayson 0:06475317f283 46 strcs r3, [r2] ; Drive the line low.
DavidEGrayson 0:06475317f283 47
DavidEGrayson 4:d3b60bd43811 48 ldr r4, =delay_region
DavidEGrayson 5:690fdfb595de 49 add r4, r4, #68
DavidEGrayson 4:d3b60bd43811 50 blx r4
DavidEGrayson 4:d3b60bd43811 51
DavidEGrayson 6:9d0530b7dae2 52 subs r7, r7, #1 ; Decrement the loop counter.
DavidEGrayson 5:690fdfb595de 53 bne send_led_strip_bit ; Send another bit if we have not reached zero.
DavidEGrayson 4:d3b60bd43811 54
DavidEGrayson 4:d3b60bd43811 55 led_strip_asm_end
DavidEGrayson 6:9d0530b7dae2 56 pop {r4, r5, r12, r7, lr}
DavidEGrayson 4:d3b60bd43811 57 bx lr
DavidEGrayson 4:d3b60bd43811 58
DavidEGrayson 4:d3b60bd43811 59
DavidEGrayson 4:d3b60bd43811 60 delay_region
DavidEGrayson 5:690fdfb595de 61 ; The following is 128 nops.
DavidEGrayson 0:06475317f283 62 nop
DavidEGrayson 0:06475317f283 63 nop
DavidEGrayson 0:06475317f283 64 nop
DavidEGrayson 0:06475317f283 65 nop
DavidEGrayson 0:06475317f283 66 nop
DavidEGrayson 0:06475317f283 67 nop
DavidEGrayson 0:06475317f283 68 nop
DavidEGrayson 0:06475317f283 69 nop
DavidEGrayson 0:06475317f283 70 nop
DavidEGrayson 0:06475317f283 71 nop
DavidEGrayson 0:06475317f283 72 nop
DavidEGrayson 0:06475317f283 73 nop
DavidEGrayson 0:06475317f283 74 nop
DavidEGrayson 4:d3b60bd43811 75 nop
DavidEGrayson 4:d3b60bd43811 76 nop
DavidEGrayson 4:d3b60bd43811 77 nop
DavidEGrayson 4:d3b60bd43811 78
DavidEGrayson 0:06475317f283 79 nop
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 0:06475317f283 93 nop
DavidEGrayson 0:06475317f283 94 nop
DavidEGrayson 4:d3b60bd43811 95
DavidEGrayson 0:06475317f283 96 nop
DavidEGrayson 0:06475317f283 97 nop
DavidEGrayson 0:06475317f283 98 nop
DavidEGrayson 0:06475317f283 99 nop
DavidEGrayson 4:d3b60bd43811 100 nop
DavidEGrayson 4:d3b60bd43811 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
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 0:06475317f283 118 nop
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 4:d3b60bd43811 125 nop
DavidEGrayson 4:d3b60bd43811 126 nop
DavidEGrayson 4:d3b60bd43811 127 nop
DavidEGrayson 4:d3b60bd43811 128 nop
DavidEGrayson 0:06475317f283 129
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 nop
DavidEGrayson 0:06475317f283 136 nop
DavidEGrayson 0:06475317f283 137 nop
DavidEGrayson 0:06475317f283 138 nop
DavidEGrayson 0:06475317f283 139 nop
DavidEGrayson 4:d3b60bd43811 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 0:06475317f283 146
DavidEGrayson 0:06475317f283 147 nop
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 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 0:06475317f283 163
DavidEGrayson 0:06475317f283 164 nop
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 4:d3b60bd43811 174 nop
DavidEGrayson 4:d3b60bd43811 175 nop
DavidEGrayson 4:d3b60bd43811 176 nop
DavidEGrayson 4:d3b60bd43811 177 nop
DavidEGrayson 4:d3b60bd43811 178 nop
DavidEGrayson 4:d3b60bd43811 179 nop
DavidEGrayson 4:d3b60bd43811 180
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 nop
DavidEGrayson 4:d3b60bd43811 187 nop
DavidEGrayson 4:d3b60bd43811 188 nop
DavidEGrayson 4:d3b60bd43811 189 nop
DavidEGrayson 4:d3b60bd43811 190 nop
DavidEGrayson 4:d3b60bd43811 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 5:690fdfb595de 197 delay_region_end
DavidEGrayson 4:d3b60bd43811 198 bx lr ; return
DavidEGrayson 0:06475317f283 199
DavidEGrayson 0:06475317f283 200 END