205 lines
6.3 KiB
C
205 lines
6.3 KiB
C
/*
|
|
* This file is part of the MicroPython project, http://micropython.org/
|
|
*
|
|
* The MIT License (MIT)
|
|
*
|
|
* Copyright (c) 2021 Jim Mussared
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
* THE SOFTWARE.
|
|
*/
|
|
|
|
#include "py/runtime.h"
|
|
#include "py/mphal.h"
|
|
#include "extmod/machine_bitstream.h"
|
|
|
|
#if MICROPY_PY_MACHINE_BITSTREAM
|
|
|
|
#if __CORTEX_M == 0
|
|
|
|
// No cycle counter on M0, do manual cycle counting instead.
|
|
|
|
// STM32F091 @ 48MHz
|
|
#define NS_CYCLES_PER_ITER_HIGH (6)
|
|
#define NS_CYCLES_PER_ITER_LOW (6)
|
|
#define NS_OVERHEAD_CYCLES_HIGH (12)
|
|
#define NS_OVERHEAD_CYCLES_LOW (18)
|
|
|
|
uint32_t mp_hal_delay_ns_calc(uint32_t ns, bool high) {
|
|
uint32_t ncycles = SystemCoreClock / 1000000 * ns / 1000;
|
|
uint32_t overhead = MIN(ncycles, high ? NS_OVERHEAD_CYCLES_HIGH : NS_OVERHEAD_CYCLES_LOW);
|
|
return MAX(1, MP_ROUND_DIVIDE(ncycles - overhead, high ? NS_CYCLES_PER_ITER_HIGH : NS_CYCLES_PER_ITER_LOW));
|
|
}
|
|
|
|
void machine_bitstream_high_low(mp_hal_pin_obj_t pin, uint32_t *timing_ns, const uint8_t *buf, size_t len) {
|
|
const uint32_t high_mask = pin->pin_mask;
|
|
const uint32_t low_mask = pin->pin_mask << 16;
|
|
volatile uint32_t *bsrr = &pin->gpio->BSRR;
|
|
|
|
// Convert ns to loop iterations [high_time_0, low_time_0, high_time_1, low_time_1].
|
|
for (size_t i = 0; i < 4; ++i) {
|
|
timing_ns[i] = mp_hal_delay_ns_calc(timing_ns[i], i % 2 == 0);
|
|
}
|
|
|
|
mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
|
|
|
|
// Measured timing for F091 at 48MHz (cycle=20.83ns)
|
|
// timing_ns = (1,1,1,1)
|
|
// high: 370
|
|
// low: 500
|
|
// low8: 660
|
|
// timing_ns = (2,2,2,2)
|
|
// high: 490
|
|
// low: 620
|
|
// low8: 805
|
|
|
|
// --> high is 12 + n*6 cycles
|
|
// low is 18 + n*6 cycles
|
|
|
|
// NeoPixel timing (400, 850, 800, 450) (+/-150ns) gives timing_ns=(1, 4, 4, 1) which in cycles is
|
|
// (12 + 6, 18 + 24, 12 + 24, 18 + 6) = (18, 42, 36, 24)
|
|
// --> (375, 875, 750, 500) nanoseconds.
|
|
// Measured output on logic analyser is (370, 870, 750, 490) (+/-10ns at 100MHz)
|
|
|
|
// Note: final low of LSB is longer by 8 cycles (160ns) (due to start of outer loop and fetching next byte).
|
|
// This is slightly outside spec, but doesn't seem to cause a problem.
|
|
|
|
__asm volatile (
|
|
// Force consistent register assignment.
|
|
// r6 = len
|
|
"ldr r6, %0\n"
|
|
// r4 = buf
|
|
"ldr r4, %1\n"
|
|
// r5 = timing_ms
|
|
"ldr r5, %2\n"
|
|
|
|
// Must align for consistent timing.
|
|
".align 4\n"
|
|
|
|
// Don't increment/decrement before first iteration.
|
|
"b .outer2\n"
|
|
".outer:\n"
|
|
// ++buf, --len
|
|
" add r4, #1\n"
|
|
" sub r6, #1\n"
|
|
|
|
// len iterations
|
|
".outer2:\n"
|
|
" cmp r6, #0\n"
|
|
" beq .done\n"
|
|
|
|
// r0 = *buf
|
|
" ldrb r0, [r4, #0]\n"
|
|
|
|
// 8 bits in byte
|
|
" mov r7, #8\n"
|
|
" .inner:\n"
|
|
// *bsrr = high_mask
|
|
" ldr r1, %3\n"
|
|
" ldr r2, %4\n"
|
|
" str r2, [r1, #0]\n"
|
|
|
|
// r3 = (r0 >> 4) & 8 (r0 is 8 if high bit is 1 else 0)
|
|
" mov r8, r6\n"
|
|
" lsr r3, r0, #4\n"
|
|
" mov r6, #8\n"
|
|
" and r3, r6\n"
|
|
" mov r6, r8\n"
|
|
|
|
// r2 = timing_ns[r2]
|
|
" ldr r2, [r5, r3]\n"
|
|
" .loop1:\n sub r2, #1\n bne .loop1\n"
|
|
|
|
// *bsrr = low_mask
|
|
" ldr r2, %5\n"
|
|
" str r2, [r1, #0]\n"
|
|
|
|
// r2 = timing_ns[r3 + 4]
|
|
" add r3, #4\n"
|
|
" ldr r2, [r5, r3]\n"
|
|
" .loop2:\n sub r2, #1\n bne .loop2\n"
|
|
|
|
// b >>= 1
|
|
" lsl r0, r0, #1\n"
|
|
|
|
" sub r7, #1\n"
|
|
// end of inner loop
|
|
" beq .outer\n"
|
|
// continue inner loop
|
|
" b .inner\n"
|
|
|
|
".done:\n"
|
|
:
|
|
: "m" (len), "m" (buf), "m" (timing_ns), "m" (bsrr), "m" (high_mask), "m" (low_mask)
|
|
: "r0", "r1", "r2", "r3", "r7", "r8"
|
|
);
|
|
|
|
MICROPY_END_ATOMIC_SECTION(atomic_state);
|
|
}
|
|
|
|
#else // > CORTEX_M0
|
|
|
|
// Use cycle counter for timing.
|
|
|
|
// Measured on PYBV11 at 168MHz & 128MHz and PYBD_SF6 at 128MHz & 144MHz.
|
|
#define NS_CYCLES_OVERHEAD (6)
|
|
|
|
void machine_bitstream_high_low(mp_hal_pin_obj_t pin, uint32_t *timing_ns, const uint8_t *buf, size_t len) {
|
|
const uint32_t high_mask = pin->pin_mask;
|
|
const uint32_t low_mask = pin->pin_mask << 16;
|
|
volatile uint32_t *bsrr = &pin->gpio->BSRR;
|
|
|
|
// Convert ns to cycles [high_time_0, low_time_0, high_time_1, low_time_1].
|
|
for (size_t i = 0; i < 4; ++i) {
|
|
timing_ns[i] = SystemCoreClock / 1000000 * timing_ns[i] / 1000;
|
|
if (timing_ns[i] > NS_CYCLES_OVERHEAD) {
|
|
timing_ns[i] -= NS_CYCLES_OVERHEAD;
|
|
}
|
|
if (i % 2 == 1) {
|
|
timing_ns[i] += timing_ns[i - 1];
|
|
}
|
|
}
|
|
|
|
mp_hal_ticks_cpu_enable();
|
|
|
|
mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
|
|
|
|
for (size_t i = 0; i < len; ++i) {
|
|
uint8_t b = buf[i];
|
|
for (size_t j = 0; j < 8; ++j) {
|
|
DWT->CYCCNT = 0;
|
|
*bsrr = high_mask;
|
|
uint32_t *t = &timing_ns[b >> 6 & 2];
|
|
while (DWT->CYCCNT < t[0]) {
|
|
;
|
|
}
|
|
*bsrr = low_mask;
|
|
b <<= 1;
|
|
while (DWT->CYCCNT < t[1]) {
|
|
;
|
|
}
|
|
}
|
|
}
|
|
|
|
MICROPY_END_ATOMIC_SECTION(atomic_state);
|
|
}
|
|
|
|
#endif // > CORTEX_M0
|
|
|
|
#endif // MICROPY_PY_MACHINE_BITSTREAM
|