0966fa8cfc
The firmware has never been flashed, and a real bug already reached the repo because of it: RD03E_FRAME_LEN was 5 for a 6-byte frame, so the footer check collided with the distance high byte and EVERY distance reading was garbage — always `lo | 0x5500`, about 218 metres, regardless of what the sensor saw. That was pure logic with no hardware dependency. It should have been catchable on a laptop, and there was simply no way to run the code. Extracted the hardware-free logic out of the three drivers — rd03e_parse, bmp280_compensate, mems_level — as moves rather than rewrites, carrying the explanatory comments along with the code they explain. The drivers now own only their bus I/O and call into the pure units, so nothing changes for the real device. `./run_tests.sh` builds them with gcc -Wall -Wextra -Werror plus a dependency-free assert harness: 175 checks, 0 failed, from a clean tree. Proven to catch the actual bug rather than assumed to: reintroducing FRAME_LEN 5 fails four checks, including one that reads "a simple-report frame is 6 bytes, not 5", plus the truncated-frame and 5-byte-window cases. Restored, green again. This does NOT make the firmware verified, and the README says so plainly — it is called a narrow exception and scoped to pure logic. Wiring, timing, real register behaviour and the reconstructed RD-03E frame format all still need the physical board. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
27 lines
707 B
C
27 lines
707 B
C
// MEMS mic level maths — pure logic. See mems_level.h.
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#include "mems_level.h"
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#include <math.h>
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double mems_level_rms(const int32_t *samples, size_t n_samples) {
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if (samples == NULL || n_samples == 0) {
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return 0.0;
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}
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double sum_sq = 0.0;
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for (size_t i = 0; i < n_samples; i++) {
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double sample = (double)(samples[i] >> 8);
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sum_sq += sample * sample;
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}
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return sqrt(sum_sq / (double)n_samples);
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}
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double mems_level_dbfs(double rms) {
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if (rms < 1.0) {
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return MEMS_DBFS_FLOOR; // effective noise floor
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}
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double dbfs = 20.0 * log10(rms / MEMS_FULL_SCALE_24BIT);
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if (dbfs < MEMS_DBFS_FLOOR) dbfs = MEMS_DBFS_FLOOR;
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return dbfs;
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}
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