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// This is a mash-up of the Due show() code + insights from Michael Miller's
// ESP8266 work for the NeoPixelBus library: github.com/Makuna/NeoPixelBus
// Needs to be a separate .c file to enforce ICACHE_RAM_ATTR execution.
#if defined(K210)
#define KENDRYTE_K210 1
#endif
#if defined(KENDRYTE_K210)
#include "sysctl.h"
#include <Arduino.h>
void k210Show(uint8_t pin, uint8_t *pixels, uint32_t numBytes,
boolean is800KHz) {
#define CYCLES_800_T0H \
(sysctl_clock_get_freq(SYSCTL_CLOCK_CPU) / 2500000) // 0.4us
#define CYCLES_800_T1H \
(sysctl_clock_get_freq(SYSCTL_CLOCK_CPU) / 1250000) // 0.8us
#define CYCLES_800 \
(sysctl_clock_get_freq(SYSCTL_CLOCK_CPU) / 800000) // 1.25us per bit
#define CYCLES_400_T0H \
(sysctl_clock_get_freq(SYSCTL_CLOCK_CPU) / 2000000) // 0.5uS
#define CYCLES_400_T1H \
(sysctl_clock_get_freq(SYSCTL_CLOCK_CPU) / 833333) // 1.2us
#define CYCLES_400 \
(sysctl_clock_get_freq(SYSCTL_CLOCK_CPU) / 400000) // 2.5us per bit
uint8_t *p, *end, pix, mask;
uint32_t t, time0, time1, period, c, startTime;
p = pixels;
end = p + numBytes;
pix = *p++;
mask = 0x80;
startTime = 0;
#ifdef NEO_KHZ400
if (is800KHz) {
#endif
time0 = CYCLES_800_T0H;
time1 = CYCLES_800_T1H;
period = CYCLES_800;
#ifdef NEO_KHZ400
} else { // 400 KHz bitstream
time0 = CYCLES_400_T0H;
time1 = CYCLES_400_T1H;
period = CYCLES_400;
}
#endif
for (t = time0;; t = time0) {
if (pix & mask)
t = time1; // Bit high duration
while (((c = read_cycle()) - startTime) < period)
; // Wait for bit start
digitalWrite(pin, HIGH);
startTime = c; // Save start time
while (((c = read_cycle()) - startTime) < t)
; // Wait high duration
digitalWrite(pin, LOW);
if (!(mask >>= 1)) { // Next bit/byte
if (p >= end)
break;
pix = *p++;
mask = 0x80;
}
}
while ((read_cycle() - startTime) < period)
; // Wait for last bit
}
#endif // KENDRYTE_K210
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