diff options
Diffstat (limited to 'olsndot/firmware/main.c')
| -rw-r--r-- | olsndot/firmware/main.c | 387 |
1 files changed, 240 insertions, 147 deletions
diff --git a/olsndot/firmware/main.c b/olsndot/firmware/main.c index 5d6c2be..a7cbbef 100644 --- a/olsndot/firmware/main.c +++ b/olsndot/firmware/main.c @@ -1,82 +1,83 @@ +/* OpenStep 2 + * Copyright (C) 2017 Sebastian Götte <code@jaseg.net> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +/* Preliminary remarks. + * + * This code is intended to run on an ARM Cortex-M0 microcontroller made by ST, part number STM32F030F4C6 + * + * Some terminology: + * + * * The term "raw channel" refers to a single output of the 32 outputs provided by the driver board. It corresponds to + * a single color sub-channel of one RGBW output. One RGBW output consists of four raw channels. + * + * * The term "logical channel" refers to one RGBW output of four individual colors handled by a group of four raw + * channels. + */ #include <stm32f0xx.h> #include <stdint.h> #include <system_stm32f0xx.h> #include <stm32f0xx_ll_utils.h> #include <math.h> -/* - * Part number: STM32F030F4C6 + +/* Bit count of this device. Note that to change this you will also have to adapt the per-bit timer period lookup table + * below. */ +#define NBITS 14 -#define NBITS 12 -void do_transpose(void); -uint32_t brightness[32]; -uint32_t sys_time = 0; -uint32_t sys_time_seconds = 0; -volatile uint32_t brightness_by_bit[NBITS]; +/* Maximum bit count supported by serial command protocol. The brightness data is assumed to be of this bit width, but + * only the uppermost NBITS bits are used. */ +#define MAX_BITS 16 -unsigned int stk_start(void) { - return SysTick->VAL; -} +void do_transpose(void); -unsigned int stk_end(unsigned int start) { - return (start - SysTick->VAL) & 0xffffff; -} +/* Right-aligned integer raw channel brightness values like so: + * + * bit index 31 ... 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 + * | (MSB) serial data put *here* (LSB) | + * |<-utterly ignored->| |<-----------------MAX_BITS------------------>| + * |<----------------NBITS---------------->| |<>|--ignored + * | (MSB) brightness data (LSB) | |<>|--ignored + */ +uint32_t brightness[32] = { 0 }; -unsigned int stk_microseconds(void) { - return sys_time*1000 + (1000 - (SysTick->VAL / (SystemCoreClock/1000000))); -} +/* Bit-golfed modulation data generated from the above values by the main loop, ready to be sent out to the shift + * registers. + */ +volatile uint32_t brightness_by_bit[NBITS] = { 0 }; -void hsv_set(int idx, int hue, int white) { - int i = hue>>NBITS; - int j = hue & (~(-1<<NBITS)); - int r=0, g=0, b=0; - switch (i) { - case 0: - r = (1<<NBITS)-1; - g = 0; - b = j; - break; - case 1: - r = (1<<NBITS)-1-j; - g = 0; - b = (1<<NBITS)-1; - break; - case 2: - r = 0; - g = j; - b = (1<<NBITS)-1; - break; - case 3: - r = 0; - g = (1<<NBITS)-1; - b = (1<<NBITS)-1-j; - break; - case 4: - r = j; - g = (1<<NBITS)-1; - b = 0; - break; - case 5: - r = (1<<NBITS)-1; - g = (1<<NBITS)-1-j; - b = 0; - break; - } - brightness[idx*4 + 0] = white; - brightness[idx*4 + 1] = r; - brightness[idx*4 + 2] = g; - brightness[idx*4 + 3] = b; -} +/* Global systick timing variables */ +uint32_t sys_time = 0; +uint32_t sys_time_seconds = 0; -int hue; int main(void) { + /* Get all the good clocks and PLLs on this thing up and running. We're running from an external 16MHz crystal, + * which we're first dividing down by 2 to get 8MHz, then PLL'ing up by 4 to get 32MHz as our main system clock. + * + * The busses are all run directly from these 32MHz because why not. + * + * Be careful in mucking around with this code since you can kind of semi-brick the chip if you do it wrong. + */ RCC->CR |= RCC_CR_HSEON; while (!(RCC->CR&RCC_CR_HSERDY)); RCC->CFGR &= ~RCC_CFGR_PLLMUL_Msk & ~RCC_CFGR_SW_Msk & ~RCC_CFGR_PPRE_Msk & ~RCC_CFGR_HPRE_Msk; - RCC->CFGR |= (2<<RCC_CFGR_PLLMUL_Pos) | RCC_CFGR_PLLSRC_HSE_PREDIV; /* PLL x4 -> 50.0MHz */ + RCC->CFGR |= (2<<RCC_CFGR_PLLMUL_Pos) | RCC_CFGR_PLLSRC_HSE_PREDIV; /* PLL x4 -> 32.0MHz */ RCC->CFGR2 &= ~RCC_CFGR2_PREDIV_Msk; - RCC->CFGR2 |= RCC_CFGR2_PREDIV_DIV2; /* prediv :2 -> 12.5MHz */ + RCC->CFGR2 |= RCC_CFGR2_PREDIV_DIV2; /* prediv :2 -> 8.0MHz */ RCC->CR |= RCC_CR_PLLON; while (!(RCC->CR&RCC_CR_PLLRDY)); RCC->CFGR |= (2<<RCC_CFGR_SW_Pos); @@ -84,10 +85,12 @@ int main(void) { SysTick_Config(SystemCoreClock/1000); /* 1ms interval */ + /* Enable all the periphery we need */ RCC->AHBENR |= RCC_AHBENR_GPIOAEN | RCC_AHBENR_GPIOBEN; RCC->APB2ENR |= RCC_APB2ENR_SPI1EN | RCC_APB2ENR_TIM1EN | RCC_APB2ENR_USART1EN | RCC_APB2ENR_ADCEN; RCC->APB1ENR |= RCC_APB1ENR_TIM3EN; + /* Configure all the GPIOs */ GPIOA->MODER |= (3<<GPIO_MODER_MODER0_Pos) /* PA0 - Current measurement analog input */ | (1<<GPIO_MODER_MODER1_Pos) /* PA1 - RS485 TX enable */ @@ -114,6 +117,7 @@ int main(void) { GPIOB->OSPEEDR |= (3<<GPIO_OSPEEDR_OSPEEDR1_Pos); /* Clear */ + /* Alternate function settings */ GPIOA->AFR[0] |= (1<<GPIO_AFRL_AFRL2_Pos) /* USART1_TX */ | (1<<GPIO_AFRL_AFRL3_Pos) /* USART1_RX */ @@ -125,35 +129,42 @@ int main(void) { (2<<GPIO_AFRL_AFRL1_Pos); /* TIM1_CH3N */ /* Configure SPI controller */ - /* CPOL=0, CPHA=0, prescaler=8 -> 1MBd */ + /* CPOL=0, CPHA=0, prescaler=2 -> 16MBd */ SPI1->CR1 = SPI_CR1_BIDIMODE | SPI_CR1_BIDIOE | SPI_CR1_SSM | SPI_CR1_SSI | SPI_CR1_SPE | (0<<SPI_CR1_BR_Pos) | SPI_CR1_MSTR; SPI1->CR2 = (0xf<<SPI_CR2_DS_Pos); /* Configure TIM1 for display strobe generation */ - TIM1->CR1 = TIM_CR1_ARPE; // | TIM_CR1_OPM; // | TIM_CR1_URS; + TIM1->CR1 = TIM_CR1_ARPE; - TIM1->PSC = 1; // debug + TIM1->PSC = 1; /* Prescale by 2, resulting in a 16MHz timer frequency and 62.5ns timer step size. */ /* CH2 - clear/!MR, CH3 - strobe/STCP */ - TIM1->CCMR2 = (6<<TIM_CCMR2_OC3M_Pos); // | TIM_CCMR2_OC3PE; + TIM1->CCMR2 = (6<<TIM_CCMR2_OC3M_Pos) | TIM_CCMR2_OC3PE; TIM1->CCER |= TIM_CCER_CC3E | TIM_CCER_CC3NE | TIM_CCER_CC3P | TIM_CCER_CC3NP; - TIM1->BDTR = TIM_BDTR_MOE | (8<<TIM_BDTR_DTG_Pos); /* 1us dead time */ - TIM1->DIER = TIM_DIER_UIE; + TIM1->BDTR = TIM_BDTR_MOE | (1<<TIM_BDTR_DTG_Pos); /* really short dead time */ + TIM1->DIER = TIM_DIER_UIE; /* Enable update (overrun) interrupt */ TIM1->ARR = 1; TIM1->CR1 |= TIM_CR1_CEN; + /* Configure Timer 1 update (overrun) interrupt on NVIC. + * Used only for update (overrun) for strobe timing. */ NVIC_EnableIRQ(TIM1_BRK_UP_TRG_COM_IRQn); NVIC_SetPriority(TIM1_BRK_UP_TRG_COM_IRQn, 2); + /* Pre-load initial values, kick of first interrupt */ TIM1->EGR |= TIM_EGR_UG; + /* Configure TIM3 for USART timeout handing */ TIM3->CR1 = TIM_CR1_OPM; TIM3->DIER = TIM_DIER_UIE; TIM3->PSC = 31; TIM3->ARR = 1000; + /* Configure Timer 3 update (overrun) interrupt on NVIC. + * Used only for update (overrun) for USART timeout handling. */ NVIC_EnableIRQ(TIM3_IRQn); NVIC_SetPriority(TIM3_IRQn, 2); + /* Pre-load initial values */ TIM3->EGR |= TIM_EGR_UG; /* Configure UART for RS485 comm */ @@ -169,47 +180,34 @@ int main(void) { /* other interrupts clear */ | USART_CR1_TE | USART_CR1_RE; - //USART1->CR2 = USART_CR2_RTOEN; /* Timeout enable */ USART1->CR3 = USART_CR3_DEM; /* RS485 DE enable (output on RTS) */ USART1->BRR = 32; USART1->CR1 |= USART_CR1_UE; - //NVIC_EnableIRQ(USART1_IRQn); + /* Configure USART1 interrupt on NVIC. Used only for RX. */ + NVIC_EnableIRQ(USART1_IRQn); NVIC_SetPriority(USART1_IRQn, 2); + /* Idly loop around, occassionally disfiguring some integers. */ while (42) { -#define HUE_MAX ((1<<NBITS)*6) -#define HUE_OFFX 0.15F /* 0-1 */ -#define HUE_AMPLITUDE 0.05F /* 0-1 */ -#define CHANNEL_SPACING 1.5F /* in radians */ -#define WHITE 0.2F /* 0-1 */ - for (float v=0; v<8*M_PI; v += 0.01F) { - GPIOA->ODR ^= GPIO_ODR_6; - /* generate hsv fade */ - for (int ch=0; ch<8; ch++) { - hue = HUE_MAX * (HUE_OFFX + HUE_AMPLITUDE*sinf(v + ch*CHANNEL_SPACING)); - hue %= HUE_MAX; - //hsv_set(ch, hue, WHITE*(1<<NBITS)); - brightness[ch*4+0] = 128; - brightness[ch*4+1] = 0; - brightness[ch*4+2] = 128; - brightness[ch*4+3] = 0; - } - do_transpose(); - for (int k=0; k<10000; k++) { - asm volatile("nop"); - } - } + /* Debug output on LED. */ + GPIOA->ODR ^= GPIO_ODR_6; + + /* Bit-mangle the integer brightness data to produce raw modulation data */ + do_transpose(); + + /* Wait a moment */ + for (int k=0; k<10000; k++) + asm volatile("nop"); } } -uint32_t brightness[32] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; -volatile uint32_t brightness_by_bit[NBITS] = { 0 }; - +/* Modulation data bit golfing routine */ void do_transpose(void) { + /* For each bit value */ for (uint32_t i=0; i<NBITS; i++) { - uint32_t bv = 0; - uint32_t mask = 1<<i<<(16-NBITS); + uint32_t mask = 1<<i<<(MAX_BITS-NBITS); /* Bit mask for this bit value. */ + uint32_t bv = 0; /* accumulator thing */ for (uint32_t j=0; j<32; j++) { if (brightness[j] & mask) bv |= 1<<j; @@ -218,45 +216,115 @@ void do_transpose(void) { } } +/* Bit timing base value. This is the lowes bit interval used */ +#define PERIOD_BASE 4 + +/* This value is a constant offset added to every bit period to allow for the timer IRQ handler to execute. This is set + * empirically using a debugger and a logic analyzer. */ +#define TIMER_CYCLES_FOR_SPI_TRANSMISSIONS 120 +/* This is the same as above, but for the reset cycle of the bit period. */ +#define RESET_PERIOD_LENGTH 40 + +/* Defines for brevity */ +#define A TIMER_CYCLES_FOR_SPI_TRANSMISSIONS +#define B PERIOD_BASE + +/* This is a constant offset containing some empirically determined correction values */ +#define C (1 /* reset pulse comp */ - 3 /* analog snafu comp */) + +/* This lookup table maps bit positions to timer period values. This is a lookup table to allow for the compensation for + * non-linear effects of ringing at lower bit durations. + */ +static uint16_t timer_period_lookup[NBITS] = { + /* LSB here */ + A - C + (B<< 0), + A - C + (B<< 1), + A - C + (B<< 2), + A - C + (B<< 3), + A - C + (B<< 4), + A - C + (B<< 5), + A - C + (B<< 6), + A - C + (B<< 7), + A - C + (B<< 8), + A - C + (B<< 9), + A - C + (B<<10), + A - C + (B<<11), + A - C + (B<<12), + A - C + (B<<13), + /* MSB here */ +}; + +/* Don't pollute the global namespace */ +#undef A +#undef B +#undef C + +/* Timer 1 main IRQ handler. This is used only for overflow ("update" or UP event in ST's terminology). */ void TIM1_BRK_UP_TRG_COM_IRQHandler(void) { /* The index of the currently active bit. On entry of this function, this is the bit index of the upcoming period. * On exit it is the index of the *next* period. */ - static uint32_t idx = 0; - - /* Access bits offset by one as we are setting the *next* period based on idx below. */ - uint32_t val = brightness_by_bit[idx]; - - idx++; - if (idx >= NBITS) - idx = 0; - - GPIOA->ODR ^= GPIO_ODR_6; /* LED1 */ - - /* Shift out the current period's data. The shift register clear and strobe lines are handled by the timers - * capture/compare channel 3 complementary outputs. The dead-time generator is used to sequence the clear and strobe - * edges one after another. Since there may be small variations in IRQ service latency it is critical to allow for - * some leeway between the end of this data transmission and strobe and clear. */ - SPI1->DR = (val&0xffff); - while (SPI1->SR & SPI_SR_BSY); - SPI1->DR = (val>>16); - while (SPI1->SR & SPI_SR_BSY); - - /* Set up everything for the *next* period. The timer is set to count from 0 to ARR. ARR and CCR3 are pre-loaded, so - * the values written above will only be latched on timer overrun at the end of this period. This is a little - * complicated, but doing it this way has the advantage of keeping both duty cycle and frame rate precisely - * constant. */ - const int period_base = 4; /* 1us */ - const int period = (period_base<<idx) + 4 /* 1us dead time */; - const int timer_cycles_for_spi_transmissions = 128; - TIM1->ARR = period + timer_cycles_for_spi_transmissions; - TIM1->CCR3 = timer_cycles_for_spi_transmissions; + static int idx = 0; + /* We modulate all outputs simultaneously in n periods, with n being the modulation depth (the number of bits). + * Each period is split into two timer cycles. First, a long one during which the data for the current period is + * shifted out and subsequently latched to the outputs. Then, a short one that is used to reset all outputs in time + * for the next period. + * + * bit value: | <-- least significant, shortest period / most significant, longest period --> | + * bit number: | b0 | b1 | ... | b10 | b11 | + * name: | data cycle | reset cycle | | | | | + * function: | shift data <strobe> wait | | ... | ... | ... | ... | + * duration: | fixed variable | fixed | | | | | + * + * Now, alternate between the two cycles in one phase. + */ + static int clear = 0; + if ((clear = !clear)) { + /* Access bits offset by one as we are setting the *next* period based on idx below. */ + uint32_t val = brightness_by_bit[idx]; + + /* Shift out the current period's data. The shift register clear and strobe lines are handled by the timers + * capture/compare channel 3 complementary outputs. The dead-time generator is used to sequence the clear and strobe + * edges one after another. Since there may be small variations in IRQ service latency it is critical to allow for + * some leeway between the end of this data transmission and strobe and clear. */ + SPI1->DR = (val&0xffff); + while (SPI1->SR & SPI_SR_BSY); + SPI1->DR = (val>>16); + while (SPI1->SR & SPI_SR_BSY); + + /* Increment the bit index for the next cycle */ + idx++; + if (idx >= NBITS) + idx = 0; + + /* Set up the following reset pulse cycle. This cycle is short as it only needs to be long enough for the below + * part of this ISR handler routine to run. */ + TIM1->ARR = RESET_PERIOD_LENGTH; + TIM1->CCR3 = 1; /* This value is fixed to produce a very short reset pulse. IOs, PCB and shift registers all can + easily handle this. */ + } else { + /* Set up everything for the data cycle of the *next* period. The timer is set to count from 0 to ARR. ARR and + * CCR3 are pre-loaded, so the values written above will only be latched on timer overrun at the end of this + * period. This is a little complicated, but doing it this way has the advantage of keeping both duty cycle and + * frame rate precisely constant. */ + TIM1->CCR3 = TIMER_CYCLES_FOR_SPI_TRANSMISSIONS; + TIM1->ARR = timer_period_lookup[idx]; + } + /* Reset the update interrupt flag. This ISR handler routine is only used for timer update events. */ TIM1->SR &= ~TIM_SR_UIF_Msk; } +/* The data format of the serial command interface. + * + * The serial interface uses short packets. Currently, there is only one packet type defined: a "set RGBW" packet, using + * command ID 0x23. The packet starts with the command ID, followed by the addressed channel group, followed by four + * times two bytes of big-endian RGBW channel data. + * + * + */ union packet { struct { uint8_t cmd; /* 0x23 */ - uint8_t step; /* 0-12, numbered from bottom */ + uint8_t step; /* logical channel. The USART_CHANNEL_OFFX is applied on this number below. */ union { uint16_t rgbw[4]; struct { @@ -276,9 +344,33 @@ void TIM3_IRQHandler(void) { rxpos = 0; } -#define USART_OFFX 8 +/* This macro defines the lowest channel number of this board on the serial command bus. On a shared bus with several + * boards, you would generally assign increasing USART_CHANNEL_OFFX values to each one (0, 8, 16, 24, ...). + * + * Example: Let USART_CHANNEL_OFFX be 8. + * + * /--Command channel number received in command packet (packet.set_step.step) + * | /--USART_OFFX + * | | /--4 raw channels per logical channel (step): R, G, B, W + * | | | /--Raw channel offset for R, G, B, W + * | | | | /--Resulting raw channels for R, G, B, W data received in command packet + * | | | | | + * v v v v v + * + * (8 - 8) * 4 + {0, 1, 2, 3} = {0, 1, 2, 3} + * (9 - 8) * 4 + {0, 1, 2, 3} + * (10 - 8) * 4 + {0, 1, 2, 3} + * (11 - 8) * 4 + {0, 1, 2, 3} + * (12 - 8) * 4 + {0, 1, 2, 3} + * (13 - 8) * 4 + {0, 1, 2, 3} + * (14 - 8) * 4 + {0, 1, 2, 3} + * (15 - 8) * 4 + {0, 1, 2, 3} + */ +#ifndef USART_CHANNEL_OFFX +#define USART_CHANNEL_OFFX 8 +#endif//USART_CHANNEL_OFFX + #define NCHANNELS (sizeof(brightness)/sizeof(brightness[0])) -int last_step = NCHANNELS/4; void USART1_IRQHandler() { static union packet rxbuf; @@ -287,36 +379,34 @@ void USART1_IRQHandler() { /* Overrun detected? */ if (isr & USART_ISR_ORE) { USART1->ICR = USART_ICR_ORECF; /* Acknowledge overrun */ - //asm("bkpt"); FIXME + //asm("bkpt"); /* uncomment for debug */ return; } if (!(isr & USART_ISR_RXNE)) { - //asm("bkpt"); FIXME + //asm("bkpt"); /* uncomment for debug */ return; } + /* Store received data */ uint8_t data = USART1->RDR; rxbuf.data[rxpos] = data; rxpos++; + /* If we finished receiving a packet, deal with it. */ if (rxpos == sizeof(union packet)) { + /* Check packet header */ if (rxbuf.set_step.cmd == 0x23 && - rxbuf.set_step.step >= USART_OFFX && - rxbuf.set_step.step < USART_OFFX+NCHANNELS) { - if (rxbuf.set_step.step != last_step+1) - if (last_step != USART_OFFX+(NCHANNELS/4)-1 && rxbuf.set_step.step != 0) { - //asm("bkpt"); - } - last_step = rxbuf.set_step.step; - - /* - if (rxbuf.set_step.step == 8 && last_step != 15) - asm("bkpt"); - */ - - uint32_t *out = &brightness[(rxbuf.set_step.step - USART_OFFX)*4]; - /* (matti) (treppe) + /* bounds-check received channel number. This allows several driver boards to share one common serial bus */ + rxbuf.set_step.step >= USART_CHANNEL_OFFX && + rxbuf.set_step.step < USART_CHANNEL_OFFX+NCHANNELS) { + + /* Calculate raw channel brightness value base address for logical channel */ + uint32_t *out = &brightness[(rxbuf.set_step.step - USART_CHANNEL_OFFX)*4]; + + /* Correct RGBW raw channel ordering per logical channel according to SUB-D pinout used. + * + * (matti) (treppe) * weiß blau * rot weiß * grün rot @@ -327,13 +417,16 @@ void USART1_IRQHandler() { out[3] = rxbuf.set_step.rgbw[2]; out[0] = rxbuf.set_step.rgbw[3]; } + /* Reset receive data counter */ rxpos = 0; } + /* Reset usart timeout handler */ TIM3->CNT = 0; TIM3->CR1 |= TIM_CR1_CEN; } +/* Misc IRQ handlers */ void NMI_Handler(void) { } @@ -357,9 +450,9 @@ void SysTick_Handler(void) { } } -/* FIXME */ +/* Misc stuff for nostdlib linking */ void _exit(int status) { while (23); } void *__bss_start__; void *__bss_end__; - int __errno; + |