6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2024-11-19 08:31:11 +00:00
Code Issues Projects Releases Wiki Activity

Starts poking at a pure total-based formula.

Browse Source 
On the assumption that any relevant DC offset will fall out in the wash. This causes one 400kb disk to boot in a Macintosh 128kb, another couple to do reasonably well. So it's better than what was here before.
This commit is contained in:
Thomas Harte 2019-07-31 12:42:23 -04:00
parent e3f22e5787
commit 260843e5b1
1 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
Machines/Apple/Macintosh/DriveSpeedAccumulator.cpp
View File

@ -26,22 +26,23 @@ void DriveSpeedAccumulator::post_sample(uint8_t sample) {
// Treat 33 as a zero point and count zero crossings; then approximate // Treat 33 as a zero point and count zero crossings; then approximate
// the RPM from the frequency of those. // the RPM from the frequency of those.
int samples_over = 0; int samples_over = 0;
int sum = 0;
const uint8_t centre = 33; const uint8_t centre = 33;
for(size_t c = 0; c < 512; ++c) { for(size_t c = 0; c < 512; ++c) {
if(samples_[c] > centre) ++ samples_over; if(samples_[c] > centre) ++ samples_over;
sum += samples_[c];
} }
// TODO: if the above is the correct test, do it on sample receipt rather than // TODO: if the above is the correct test, do it on sample receipt rather than
// bothering with an intermediate buffer. // bothering with an intermediate buffer.
// The below fits for a function like `a + bc`; I'm not sure it's // The below fits for a function like `a + bc`.
const float duty_cycle = float(samples_over) / float(samples_.size()); const float rotation_speed = (float(sum) * 0.052896440564137f) - 259.0f;
const float rotation_speed = 392.0f + duty_cycle * 19.95f;
for(int c = 0; c < number_of_drives_; ++c) { for(int c = 0; c < number_of_drives_; ++c) {
drives_[c]->set_rotation_speed(rotation_speed); drives_[c]->set_rotation_speed(rotation_speed);
} }
// printf("RPM: %0.2f (%d over)\n", rotation_speed, samples_over); // printf("RPM: %0.2f (%d over; %d sum)\n", rotation_speed, samples_over, sum);
} }
} }