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ScottW514
fb956971b7
Direct PWMSAR duty steps with the machine in the locked state (controller stopped, cnc disabled so steppers are unpowered, laser latch locked, lid closed; laser_on_sampled stayed 0 throughout). Measured on the pin: 25.0 us period / 40 kHz stable across the full duty range; 50/25/75 percent confirmed visually; low end cursor-measured 6.4 vs 6.3 percent commanded (PWMSAR=8), clean pulse. Matches the register-level audit numbers (divider 13 x 127 counts). Adds pwm_sweep.py / pwm_hold.py to the bench kit and records the two remaining pre-live-fire gates (1-tick laser drop at underrun via the stream path with FIRE observable under a locked latch; interlock readback semantics) in BRINGUP.
25 lines
932 B
Python
25 lines
932 B
Python
#!/usr/bin/env python3
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"""Hold LASER_PWM at one duty value for a measurement window, then restore.
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Usage: pwm_hold.py [sar] [seconds] (defaults: 8, 30)"""
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import mmap, struct, sys, time
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PWM2_BASE = 0x02084000
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SAR_OFF = 0x0C
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sar = int(sys.argv[1]) if len(sys.argv) > 1 else 8
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secs = int(sys.argv[2]) if len(sys.argv) > 2 else 30
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with open('/dev/mem', 'r+b') as f:
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m = mmap.mmap(f.fileno(), 4096, mmap.MAP_SHARED,
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mmap.PROT_READ | mmap.PROT_WRITE, offset=PWM2_BASE)
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sar0 = struct.unpack('<I', m[SAR_OFF:SAR_OFF + 4])[0]
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m[SAR_OFF:SAR_OFF + 4] = struct.pack('<I', sar)
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print('PWMSAR=%d held for %d s (was %d)...' % (sar, secs, sar0))
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sys.stdout.flush()
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time.sleep(secs)
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m[SAR_OFF:SAR_OFF + 4] = struct.pack('<I', sar0)
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print('restored PWMSAR=%d' % sar0)
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with open('/sys/glowforge/cnc/laser_on_sampled') as s:
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print('laser_on_sampled =', s.read().strip())
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m.close()
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