Michael Koster / PololuLedStrip_r8

debug

Fork of PololuLedStripx by Michael Koster

PololuLedStrip.cpp@8:1578776ceac5, 2013-03-01 (annotated)

Committer:
DavidEGrayson
Date:
Fri Mar 01 02:05:21 2013 +0000
Revision:
8:1578776ceac5
Parent:
7:9a088f042ee0
Child:
9:6ffb85d69eaf
Changed the registers so that the push and pop commands can work on the Cortex M0 (LPC 11U24).  There are still more things to fix though.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
DavidEGrayson 1:102307d9b701 1 #include "PololuLedStrip.h"
DavidEGrayson 1:102307d9b701 2
DavidEGrayson 1:102307d9b701 3 bool PololuLedStrip::interruptFriendly = false;
DavidEGrayson 1:102307d9b701 4
DavidEGrayson 7:9a088f042ee0 5 uint8_t led_strip_write_delays[3];
DavidEGrayson 4:d3b60bd43811 6
DavidEGrayson 7:9a088f042ee0 7 void PololuLedStrip::calculateDelays()
DavidEGrayson 7:9a088f042ee0 8 {
DavidEGrayson 8:1578776ceac5 9 // Get the clock frequency in MHz.
DavidEGrayson 8:1578776ceac5 10 int f_mhz = SystemCoreClock / 1000000;
DavidEGrayson 8:1578776ceac5 11
DavidEGrayson 8:1578776ceac5 12 // Arrange for a 700 nanosecond delay between the rise time and the fall time for a 0 bit.
DavidEGrayson 8:1578776ceac5 13 led_strip_write_delays[0] = 700*f_mhz/1000 - 25;
DavidEGrayson 8:1578776ceac5 14
DavidEGrayson 8:1578776ceac5 15 // Arrange for a 600 nanosecond delay between the fall time for a 0 bit and the fall time for a 1 bit.
DavidEGrayson 8:1578776ceac5 16 // This means the pulses representing a 1 will be 700+600 = 1300 nanoseconds.
DavidEGrayson 8:1578776ceac5 17 led_strip_write_delays[1] = 600*f_mhz/1000 - 19;
DavidEGrayson 8:1578776ceac5 18
DavidEGrayson 8:1578776ceac5 19 // Arrange for a 1200 nanosecond delay between the fall time for a 1 bit and rise time of the next bit.
DavidEGrayson 8:1578776ceac5 20 // This means the period of the signal will be 2500 nanoseconds.
DavidEGrayson 8:1578776ceac5 21 led_strip_write_delays[2] = 1200*f_mhz/1000 - 24;
DavidEGrayson 7:9a088f042ee0 22 }
DavidEGrayson 6:9d0530b7dae2 23
DavidEGrayson 1:102307d9b701 24 PololuLedStrip::PololuLedStrip(PinName pinName)
DavidEGrayson 1:102307d9b701 25 {
DavidEGrayson 1:102307d9b701 26 gpio_init(&gpio, pinName, PIN_OUTPUT);
DavidEGrayson 1:102307d9b701 27 }
DavidEGrayson 1:102307d9b701 28
DavidEGrayson 1:102307d9b701 29 void PololuLedStrip::write(rgb_color * colors, unsigned int count)
DavidEGrayson 1:102307d9b701 30 {
DavidEGrayson 8:1578776ceac5 31 calculateDelays();
DavidEGrayson 8:1578776ceac5 32
DavidEGrayson 1:102307d9b701 33 __disable_irq(); // Disable interrupts temporarily because we don't want our pulse timing to be messed up.
DavidEGrayson 7:9a088f042ee0 34
DavidEGrayson 1:102307d9b701 35 while(count--)
DavidEGrayson 1:102307d9b701 36 {
DavidEGrayson 1:102307d9b701 37 led_strip_write_color(colors++, gpio.reg_set, gpio.reg_clr, gpio.mask);
DavidEGrayson 1:102307d9b701 38
DavidEGrayson 1:102307d9b701 39 if (interruptFriendly)
DavidEGrayson 1:102307d9b701 40 {
DavidEGrayson 1:102307d9b701 41 __enable_irq();
DavidEGrayson 1:102307d9b701 42 __nop();
DavidEGrayson 1:102307d9b701 43 __nop();
DavidEGrayson 1:102307d9b701 44 __nop();
DavidEGrayson 1:102307d9b701 45 __disable_irq();
DavidEGrayson 1:102307d9b701 46 }
DavidEGrayson 1:102307d9b701 47 }
DavidEGrayson 1:102307d9b701 48
DavidEGrayson 1:102307d9b701 49 __enable_irq(); // Re-enable interrupts now that we are done.
DavidEGrayson 1:102307d9b701 50 wait_us(24); // Hold the line low for 24 microseconds to send the reset signal.
DavidEGrayson 1:102307d9b701 51 }