627ceebef3
* ws2812: Fix number of nops for AVR at 8 MHz When trying to calculate the number of nops for AVR running at 8 MHz, the value of `w3` is expected to be negative; however, because `F_CPU` is defined in tmk_core/avr.mk with the `UL` suffix, the preprocessor performs its calculations using `unsigned long`, getting a very large positive number instead of the expected negative number; this then results in generating code with a huge number of nops. Fix the broken calculations by performing a comparison before subtraction, so that the unsigned number wraparound does not occur. The keyboard which triggers the problem is `handwired/promethium`; the buggy code silently compiles, but the resulting timings would be completely wrong. * ws2812: Clean up the code after the 8 MHz fix Remove old code which was unsuccessfully trying to clamp negative w1, w2 and w3 values to 0, and set w1_nops, w2_nops and w3_nops directly.
176 lines
5.3 KiB
C
176 lines
5.3 KiB
C
/*
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* light weight WS2812 lib V2.0b
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*
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* Controls WS2811/WS2812/WS2812B RGB-LEDs
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* Author: Tim (cpldcpu@gmail.com)
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*
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* Jan 18th, 2014 v2.0b Initial Version
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* Nov 29th, 2015 v2.3 Added SK6812RGBW support
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "ws2812.h"
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#include <avr/interrupt.h>
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#include <avr/io.h>
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#include <util/delay.h>
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#define pinmask(pin) (_BV((pin)&0xF))
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/*
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* Forward declare internal functions
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*
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* The functions take a byte-array and send to the data output as WS2812 bitstream.
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* The length is the number of bytes to send - three per LED.
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*/
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static inline void ws2812_sendarray_mask(uint8_t *data, uint16_t datlen, uint8_t masklo, uint8_t maskhi);
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void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds) {
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DDRx_ADDRESS(RGB_DI_PIN) |= pinmask(RGB_DI_PIN);
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uint8_t masklo = ~(pinmask(RGB_DI_PIN)) & PORTx_ADDRESS(RGB_DI_PIN);
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uint8_t maskhi = pinmask(RGB_DI_PIN) | PORTx_ADDRESS(RGB_DI_PIN);
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ws2812_sendarray_mask((uint8_t *)ledarray, number_of_leds * sizeof(LED_TYPE), masklo, maskhi);
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_delay_us(WS2812_TRST_US);
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}
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/*
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This routine writes an array of bytes with RGB values to the Dataout pin
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using the fast 800kHz clockless WS2811/2812 protocol.
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*/
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// Timing in ns
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#define w_zeropulse 350
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#define w_onepulse 900
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#define w_totalperiod 1250
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// Fixed cycles used by the inner loop
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#define w_fixedlow 2
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#define w_fixedhigh 4
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#define w_fixedtotal 8
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// Insert NOPs to match the timing, if possible
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#define w_zerocycles (((F_CPU / 1000) * w_zeropulse) / 1000000)
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#define w_onecycles (((F_CPU / 1000) * w_onepulse + 500000) / 1000000)
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#define w_totalcycles (((F_CPU / 1000) * w_totalperiod + 500000) / 1000000)
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// w1_nops - nops between rising edge and falling edge - low
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#if w_zerocycles >= w_fixedlow
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# define w1_nops (w_zerocycles - w_fixedlow)
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#else
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# define w1_nops 0
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#endif
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// w2_nops - nops between fe low and fe high
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#if w_onecycles >= (w_fixedhigh + w1_nops)
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# define w2_nops (w_onecycles - w_fixedhigh - w1_nops)
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#else
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# define w2_nops 0
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#endif
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// w3_nops - nops to complete loop
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#if w_totalcycles >= (w_fixedtotal + w1_nops + w2_nops)
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# define w3_nops (w_totalcycles - w_fixedtotal - w1_nops - w2_nops)
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#else
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# define w3_nops 0
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#endif
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// The only critical timing parameter is the minimum pulse length of the "0"
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// Warn or throw error if this timing can not be met with current F_CPU settings.
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#define w_lowtime ((w1_nops + w_fixedlow) * 1000000) / (F_CPU / 1000)
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#if w_lowtime > 550
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# error "Light_ws2812: Sorry, the clock speed is too low. Did you set F_CPU correctly?"
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#elif w_lowtime > 450
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# warning "Light_ws2812: The timing is critical and may only work on WS2812B, not on WS2812(S)."
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# warning "Please consider a higher clockspeed, if possible"
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#endif
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#define w_nop1 "nop \n\t"
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#define w_nop2 "rjmp .+0 \n\t"
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#define w_nop4 w_nop2 w_nop2
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#define w_nop8 w_nop4 w_nop4
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#define w_nop16 w_nop8 w_nop8
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static inline void ws2812_sendarray_mask(uint8_t *data, uint16_t datlen, uint8_t masklo, uint8_t maskhi) {
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uint8_t curbyte, ctr, sreg_prev;
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sreg_prev = SREG;
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cli();
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while (datlen--) {
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curbyte = (*data++);
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asm volatile(" ldi %0,8 \n\t"
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"loop%=: \n\t"
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" out %2,%3 \n\t" // '1' [01] '0' [01] - re
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#if (w1_nops & 1)
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w_nop1
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#endif
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#if (w1_nops & 2)
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w_nop2
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#endif
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#if (w1_nops & 4)
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w_nop4
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#endif
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#if (w1_nops & 8)
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w_nop8
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#endif
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#if (w1_nops & 16)
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w_nop16
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#endif
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" sbrs %1,7 \n\t" // '1' [03] '0' [02]
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" out %2,%4 \n\t" // '1' [--] '0' [03] - fe-low
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" lsl %1 \n\t" // '1' [04] '0' [04]
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#if (w2_nops & 1)
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w_nop1
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#endif
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#if (w2_nops & 2)
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w_nop2
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#endif
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#if (w2_nops & 4)
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w_nop4
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#endif
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#if (w2_nops & 8)
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w_nop8
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#endif
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#if (w2_nops & 16)
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w_nop16
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#endif
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" out %2,%4 \n\t" // '1' [+1] '0' [+1] - fe-high
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#if (w3_nops & 1)
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w_nop1
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#endif
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#if (w3_nops & 2)
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w_nop2
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#endif
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#if (w3_nops & 4)
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w_nop4
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#endif
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#if (w3_nops & 8)
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w_nop8
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#endif
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#if (w3_nops & 16)
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w_nop16
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#endif
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" dec %0 \n\t" // '1' [+2] '0' [+2]
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" brne loop%=\n\t" // '1' [+3] '0' [+4]
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: "=&d"(ctr)
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: "r"(curbyte), "I"(_SFR_IO_ADDR(PORTx_ADDRESS(RGB_DI_PIN))), "r"(maskhi), "r"(masklo));
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}
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SREG = sreg_prev;
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}
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