[goggles] / ws2811.c

#include <stdint.h>
#include <stdbool.h>

#include "user.h"

#include "ws2811.h"

/* this holds the G R B bytes for the entire string */
unsigned char rgbdata[RGB_COUNT];


/* These values are placed in common memory so that they can be accessed
 * quickly without a bank switch by the routines below, THIS IS IMPORTANT,
 * it will not run properly without it */
volatile uint8_t rgb_sample @ 0x7B;
volatile uint8_t rgb_byte @ 0x7C;
volatile uint8_t rgb_bit @ 0x7D;

// send the whole pile of data
static void ws2811_send(void)
{
#asm
    // copy the led colour array location into FSR0 for fast access
    MOVLW HIGH _rgbdata
    MOVWF FSR0H
    MOVLW LOW _rgbdata
    MOVWF FSR0L

    // load next byte from array into working reg
ws2811_nextbyte:
    MOVIW FSR0++
    MOVWF _rgb_sample
    MOVLW 8 // reset bit count
    MOVWF _rgb_bit

ws2811_sendbit:
    // you assume its a zero then test if its one
//    MOVLW 0xC0 ;11000000B
    MOVLW 0x80 ;10000000B
    
    RLF _rgb_sample,f
    BTFSC STATUS,0  // CARRY
    //asm("MOVLW 0xF8 "); // 11111000B
    MOVLW 0xF0      // 11110000B

    BANKSEL (SSP1BUF)
    MOVWF BANKMASK(SSP1BUF)

    // any more bits
    DECFSZ _rgb_bit,f
    BRA ws2811_delay

    // any more bytes
    DECFSZ _rgb_byte,f
    BRA ws2811_nextbyte
    BRA ws2811_end

ws2811_delay:
    NOP
    NOP
    NOP
    BRA ws2811_sendbit

ws2811_end:


#endasm

    // all done
}

#if _XTAL_FREQ != 32000000L
#error "This code requires 32MHz system clock or above"
#endif

void ws2811_init(void)
{
    // SPI is on RA0
    TRISAbits.TRISA0 = 0; // SDO is RA0
    ANSELAbits.ANSA0 = 0; // not analog

    // SCK (SPI Clock) is RA1
    // SDI (SPI In) is RA2
    APFCONbits.SDOSEL = 0; // use RA0 not RA4 for output

    // at 8MHz Tclk   0 = 2 bits, 1 = 6 bits.
    // write to SSP1BUF
    SSP1CON1bits.SSPM = 0b0000; // SPI Master Fosc/4
    SSP1CON1bits.SSPEN = 1; // enable MSSP
}

void ws2811_transmit(void)
{
    rgb_byte = RGB_COUNT;
    ws2811_send(); // send the first bit
}
Commit	Line	Data
	1	#include <stdint.h>
	2	#include <stdbool.h>
	3
	4	#include "user.h"
	5
	6	#include "ws2811.h"
	7
	8	/* this holds the G R B bytes for the entire string */
	9	unsigned char rgbdata[RGB_COUNT];
	10
	11
	12	/* These values are placed in common memory so that they can be accessed
	13	* quickly without a bank switch by the routines below, THIS IS IMPORTANT,
	14	* it will not run properly without it */
	15	volatile uint8_t rgb_sample @ 0x7B;
	16	volatile uint8_t rgb_byte @ 0x7C;
	17	volatile uint8_t rgb_bit @ 0x7D;
	18
	19	// send the whole pile of data
	20	static void ws2811_send(void)
	21	{
	22	#asm
	23	// copy the led colour array location into FSR0 for fast access
	24	MOVLW HIGH _rgbdata
	25	MOVWF FSR0H
	26	MOVLW LOW _rgbdata
	27	MOVWF FSR0L
	28
	29	// load next byte from array into working reg
	30	ws2811_nextbyte:
	31	MOVIW FSR0++
	32	MOVWF _rgb_sample
	33	MOVLW 8 // reset bit count
	34	MOVWF _rgb_bit
	35
	36	ws2811_sendbit:
	37	// you assume its a zero then test if its one
	38	// MOVLW 0xC0 ;11000000B
	39	MOVLW 0x80 ;10000000B
	40
	41	RLF _rgb_sample,f
	42	BTFSC STATUS,0 // CARRY
	43	//asm("MOVLW 0xF8 "); // 11111000B
	44	MOVLW 0xF0 // 11110000B
	45
	46	BANKSEL (SSP1BUF)
	47	MOVWF BANKMASK(SSP1BUF)
	48
	49	// any more bits
	50	DECFSZ _rgb_bit,f
	51	BRA ws2811_delay
	52
	53	// any more bytes
	54	DECFSZ _rgb_byte,f
	55	BRA ws2811_nextbyte
	56	BRA ws2811_end
	57
	58	ws2811_delay:
	59	NOP
	60	NOP
	61	NOP
	62	BRA ws2811_sendbit
	63
	64	ws2811_end:
	65
	66
	67	#endasm
	68
	69	// all done
	70	}
	71
	72	#if _XTAL_FREQ != 32000000L
	73	#error "This code requires 32MHz system clock or above"
	74	#endif
	75
	76	void ws2811_init(void)
	77	{
	78	// SPI is on RA0
	79	TRISAbits.TRISA0 = 0; // SDO is RA0
	80	ANSELAbits.ANSA0 = 0; // not analog
	81
	82	// SCK (SPI Clock) is RA1
	83	// SDI (SPI In) is RA2
	84	APFCONbits.SDOSEL = 0; // use RA0 not RA4 for output
	85
	86	// at 8MHz Tclk 0 = 2 bits, 1 = 6 bits.
	87	// write to SSP1BUF
	88	SSP1CON1bits.SSPM = 0b0000; // SPI Master Fosc/4
	89	SSP1CON1bits.SSPEN = 1; // enable MSSP
	90	}
	91
	92	void ws2811_transmit(void)
	93	{
	94	rgb_byte = RGB_COUNT;
	95	ws2811_send(); // send the first bit
	96	}