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2 mjames 1 
/*
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 * leds.c
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 *
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 *  Created on: 7 Jul 2019
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 *      Author: Mike
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 */
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#include "main.h"
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#include "leds.h"
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// Target clock rate 800 kHz
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#define SPICLOCK 9000000UL
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// one clock of SPI is 166nS
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#define TSPI (1000000000UL/SPICLOCK)
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// reset period is 50000nS
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#define TRESET 50000
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// total bit period is 1250nS or 1/800kHz
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#define TBIT  1250
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// to produce '0' value go high for 400nS, low for 850nS
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#define T0H    400
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#define T0L    850
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// to produce '1' value go high for 850nS, low for 400nS
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#define T1H    850
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#define T1L    400
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#define BUFFER_SIZE 1000
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uint8_t buffer [BUFFER_SIZE];
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// byte pointer
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unsigned bufPtr;
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// bit index pointer
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uint8_t bitPtr;
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// bit transmission time offset from start of transmission
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unsigned SPItime = 0;
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DMX_State_t DMX_State = DMX_IDLE;
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unsigned RealTime = 0;
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static volatile uint8_t busy = 0;
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void initCode(void)
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{
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        bufPtr = 0;
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        bitPtr = 0;
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        SPItime  = 0;
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        RealTime = 0;
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}
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// send a '1' or '0' on SPI bus
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void codeBit(uint8_t val, unsigned until)
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{
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        // calculate true limit time
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        RealTime += until;
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        while(SPItime< RealTime)
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        {
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        if(val)
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          buffer[bufPtr] |= (1<<bitPtr);
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        else
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      buffer[bufPtr] &= ~(1<<bitPtr);
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        bitPtr++;
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        if(bitPtr == 8)
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        {
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                bitPtr = 0;
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                bufPtr ++;
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        }
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        // accumulate transmission time on SPI bus
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        SPItime += TSPI;
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        if(bufPtr >= BUFFER_SIZE)
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                bufPtr = BUFFER_SIZE-1; // limit
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        }
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}
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void codeReset (void)
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{
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                codeBit(0,TRESET);
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}
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// send a single Run Length code bit
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void codeRL(uint8_t bit)
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{
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        unsigned lim = bit ? T1H : T0H;
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        codeBit(1,lim);
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        codeBit(0,TBIT-lim);
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}
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// code a byte using the RL code
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void codeRLByte(uint8_t val)
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{
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        uint8_t i;
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                for (i=0; i<8; i++)
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                {
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                        codeRL(val & 0x80);
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                        val<<=1;
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                }
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}
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void codeFRGB(frgb_t led )
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{
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                codeRLByte(((uint16_t)(led.green) * led.fader)/256);
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                codeRLByte(((uint16_t)(led.red) * led.fader)/256);
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                codeRLByte(((uint16_t)(led.blue) * led.fader)/256);
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}
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frgb_t led0 = { 128, 0, 0, 0 };
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frgb_t ledZ = { 0,0,0,0 };
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void sendLeds()
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{
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        initCode();
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        codeReset();
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    led0.green++;
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        led0.fader++;
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    if(led0.green %4 == 0)
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                led0.red --;
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        if(led0.green %55 == 0)
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                led0.blue +=123;
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        codeFRGB(led0);
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        // send terminal
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        codeFRGB(ledZ);
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     busy= 1;
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        HAL_SPI_Transmit_DMA(&hspi1,buffer,bufPtr+1);
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  //
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        while(busy) {};
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}
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void HAL_SPI_TxCpltCallback( SPI_HandleTypeDef * hspi)
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{
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        (void ) hspi;
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        busy = 0;
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}
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