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Make DELAY_NS round up on AVR (#21546)

vanilla_fb_2.0.x
Mike La Spina 4 years ago
committed by GitHub
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commit
993609b5aa
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  1. 35
      Marlin/src/HAL/shared/Delay.h
  2. 2
      Marlin/src/lcd/dogm/ultralcd_st7920_u8glib_rrd_AVR.cpp

35
Marlin/src/HAL/shared/Delay.h

@ -150,8 +150,37 @@ void calibrate_delay_loop();
#endif #endif
// Delay in nanoseconds /**************************************************************
#define DELAY_NS(x) DELAY_CYCLES((x) * ((F_CPU) / 1000000UL) / 1000UL) * Delay in nanoseconds. Requires the F_CPU macro.
* These macros follow avr-libc delay conventions.
*
* For AVR there are three possible operation modes, due to its
* slower clock speeds and thus coarser delay resolution. For
* example, when F_CPU = 16000000 the resolution is 62.5ns.
*
* Round up (default)
* Round up the delay according to the CPU clock resolution.
* e.g., 100 will give a delay of 2 cycles (125ns).
*
* Round down (DELAY_NS_ROUND_DOWN)
* Round down the delay according to the CPU clock resolution.
* e.g., 100 will be rounded down to 1 cycle (62.5ns).
*
* Nearest (DELAY_NS_ROUND_CLOSEST)
* Round the delay to the nearest number of clock cycles.
* e.g., 165 will be rounded up to 3 cycles (187.5ns) because
* it's closer to the requested delay than 2 cycle (125ns).
*/
#ifndef __AVR__
#undef DELAY_NS_ROUND_DOWN
#undef DELAY_NS_ROUND_CLOSEST
#endif
#if ENABLED(DELAY_NS_ROUND_DOWN)
#define DELAY_NS(x) DELAY_CYCLES((x) * ((F_CPU) / 1000000UL) / 1000UL) // floor
#elif ENABLED(DELAY_NS_ROUND_CLOSEST)
#define DELAY_NS(x) DELAY_CYCLES(((x) * ((F_CPU) / 1000000UL) + 500) / 1000UL) // round
#else
#define DELAY_NS(x) DELAY_CYCLES(((x) * ((F_CPU) / 1000000UL) + 999) / 1000UL) // "ceil"
#endif

2
Marlin/src/lcd/dogm/ultralcd_st7920_u8glib_rrd_AVR.cpp

@ -60,7 +60,7 @@
#elif F_CPU == 16000000 #elif F_CPU == 16000000
#define CPU_ST7920_DELAY_1 DELAY_NS(125) #define CPU_ST7920_DELAY_1 DELAY_NS(125)
#define CPU_ST7920_DELAY_2 DELAY_NS(0) #define CPU_ST7920_DELAY_2 DELAY_NS(0)
#define CPU_ST7920_DELAY_3 DELAY_NS(125) #define CPU_ST7920_DELAY_3 DELAY_NS(188)
#else #else
#error "No valid condition for delays in 'ultralcd_st7920_u8glib_rrd_AVR.h'" #error "No valid condition for delays in 'ultralcd_st7920_u8glib_rrd_AVR.h'"
#endif #endif

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