Sorry, I forgot to include the current sketch used.
I should also add that I've been using a baud of 1000000 without any errors.
Here it is:
#include "FastLED.h"
#define NUM_LEDS 104 // Max LED count
#define LED_PIN 6 // arduino output pin
#define GROUND_PIN 10
#define BRIGHTNESS 255 // maximum brightness
// #define SPEED 115200 // virtual serial port speed, must be the same in boblight_config
#define SPEED 1000000 // appears to work, used for over a month without FPS drop
CRGB leds[NUM_LEDS];
uint8_t * ledsRaw = (uint8_t *)leds;
// A 'magic word' (along with LED count & checksum) precedes each block
// of LED data; this assists the microcontroller in syncing up with the
// host-side software and properly issuing the latch (host I/O is
// likely buffered, making usleep() unreliable for latch). You may see
// an initial glitchy frame or two until the two come into alignment.
// The magic word can be whatever sequence you like, but each character
// should be unique, and frequent pixel values like 0 and 255 are
// avoided -- fewer false positives. The host software will need to
// generate a compatible header: immediately following the magic word
// are three bytes: a 16-bit count of the number of LEDs (high byte
// first) followed by a simple checksum value (high byte XOR low byte
// XOR 0x55). LED data follows, 3 bytes per LED, in order R, G, B,
// where 0 = off and 255 = max brightness.
static const uint8_t magic[] = {
'A','d','a'};
#define MAGICSIZE sizeof(magic)
#define HEADERSIZE (MAGICSIZE + 3)
#define MODE_HEADER 0
#define MODE_DATA 2
// If no serial data is received for a while, the LEDs are shut off
// automatically. This avoids the annoying "stuck pixel" look when
// quitting LED display programs on the host computer.
static const unsigned long serialTimeout = 150000; // 150 seconds
void setup()
{
pinMode(GROUND_PIN, OUTPUT);
digitalWrite(GROUND_PIN, LOW);
FastLED.addLeds<WS2812B, LED_PIN, GRB>(leds, NUM_LEDS);
// Dirty trick: the circular buffer for serial data is 256 bytes,
// and the "in" and "out" indices are unsigned 8-bit types -- this
// much simplifies the cases where in/out need to "wrap around" the
// beginning/end of the buffer. Otherwise there'd be a ton of bit-
// masking and/or conditional code every time one of these indices
// needs to change, slowing things down tremendously.
uint8_t
buffer[256],
indexIn = 0,
indexOut = 0,
mode = MODE_HEADER,
hi, lo, chk, i, spiFlag;
int16_t
bytesBuffered = 0,
hold = 0,
c;
int32_t
bytesRemaining;
unsigned long
startTime,
lastByteTime,
lastAckTime,
t;
int32_t outPos = 0;
Serial.begin(SPEED); // Teensy/32u4 disregards baud rate; is OK!
Serial.print("Ada\n"); // Send ACK string to host
startTime = micros();
lastByteTime = lastAckTime = millis();
// loop() is avoided as even that small bit of function overhead
// has a measurable impact on this code's overall throughput.
for(;;) {
// Implementation is a simple finite-state machine.
// Regardless of mode, check for serial input each time:
t = millis();
if((bytesBuffered < 256) && ((c = Serial.read()) >= 0)) {
buffer[indexIn++] = c;
bytesBuffered++;
lastByteTime = lastAckTime = t; // Reset timeout counters
}
else {
// No data received. If this persists, send an ACK packet
// to host once every second to alert it to our presence.
if((t - lastAckTime) > 1000) {
Serial.print("Ada\n"); // Send ACK string to host
lastAckTime = t; // Reset counter
}
// If no data received for an extended time, turn off all LEDs.
if((t - lastByteTime) > serialTimeout) {
memset(leds, 0, NUM_LEDS * sizeof(struct CRGB)); //filling Led array by zeroes
FastLED.show();
lastByteTime = t; // Reset counter
}
}
switch(mode) {
case MODE_HEADER:
// In header-seeking mode. Is there enough data to check?
if(bytesBuffered >= HEADERSIZE) {
// Indeed. Check for a 'magic word' match.
for(i=0; (i<MAGICSIZE) && (buffer[indexOut++] == magic[i++]););
if(i == MAGICSIZE) {
// Magic word matches. Now how about the checksum?
hi = buffer[indexOut++];
lo = buffer[indexOut++];
chk = buffer[indexOut++];
if(chk == (hi ^ lo ^ 0x55)) {
// Checksum looks valid. Get 16-bit LED count, add 1
// (# LEDs is always > 0) and multiply by 3 for R,G,B.
bytesRemaining = 3L * (256L * (long)hi + (long)lo + 1L);
bytesBuffered -= 3;
outPos = 0;
memset(leds, 0, NUM_LEDS * sizeof(struct CRGB));
mode = MODE_DATA; // Proceed to latch wait mode
}
else {
// Checksum didn't match; search resumes after magic word.
indexOut -= 3; // Rewind
}
} // else no header match. Resume at first mismatched byte.
bytesBuffered -= i;
}
break;
case MODE_DATA:
if(bytesRemaining > 0) {
if(bytesBuffered > 0) {
if (outPos < sizeof(leds))
ledsRaw[outPos++] = buffer[indexOut++]; // Issue next byte
bytesBuffered--;
bytesRemaining--;
}
// If serial buffer is threatening to underrun, start
// introducing progressively longer pauses to allow more
// data to arrive (up to a point).
}
else {
// End of data -- issue latch:
startTime = micros();
mode = MODE_HEADER; // Begin next header search
FastLED.show();
/// This part drains the buffer and stops flicker, not included with standard file
while(Serial.available()>0){ Serial.read(); }
}
} // end switch
} // end for(;;)
}
void loop()
{
// Not used. See note in setup() function.
}
