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https://github.com/openglow-org/forgefirm.git
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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.
75 lines
2.6 KiB
Python
75 lines
2.6 KiB
Python
#!/usr/bin/env python3
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"""LASER_PWM scope test - runs ON the board.
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check: read-only - safety-chain readbacks + PWM2 register dump.
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sweep: step the PWM duty register through known values with pauses so
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the scope can capture each, then restore the original sample.
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The duty register (PWMSAR) is the laser power SETPOINT only. No motion
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subsystem is touched (steppers are disabled before this runs), no
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stream runs, the laser latch is locked, FIRE is never asserted.
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"""
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import mmap, struct, sys, time
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PWM2_BASE = 0x02084000
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PERCLK_HZ = 66_000_000
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SAR_OFF = 0x0C
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def rd(name):
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try:
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with open('/sys/glowforge/' + name) as f:
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return f.read().strip()
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except OSError as e:
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return '<%s>' % e
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def dump_regs(m):
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cr, sr, ir, sar, pr = struct.unpack('<5I', m[:20])
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divider = ((cr >> 4) & 0xFFF) + 1
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counts = pr + 2
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freq = PERCLK_HZ / (divider * counts) if counts else 0
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print('PWMCR=0x%08x PWMSAR=%d PWMPR=%d enabled=%s divider=%d counts=%d carrier=%.2f kHz'
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% (cr, sar, pr, bool(cr & 1), divider, counts, freq / 1000))
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return sar, pr
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def safety_readback():
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print('cnc/state =', rd('cnc/state'))
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print('cnc/laser_on =', rd('cnc/laser_on'))
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print('cnc/laser_enable =', rd('cnc/laser_enable'))
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print('cnc/laser_pgood =', rd('cnc/laser_pgood'))
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print('cnc/interlock_circuit =', rd('cnc/interlock_circuit'),
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'(b0 LASER_ON b1 LASER_ENABLE b2 BUTTON_LATCH b3 LASER_LATCH b4 ILK_RESET)')
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print('cnc/laser_on_sampled =', rd('cnc/laser_on_sampled'))
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mode = sys.argv[1] if len(sys.argv) > 1 else 'check'
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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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print('--- safety readback (before)')
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safety_readback()
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print('--- PWM2 registers')
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sar0, pr = dump_regs(m)
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if mode == 'sweep':
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period = pr + 2
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steps = [(64, '50%'), (32, '25%'), (96, '75%'), (8, '6%'), (127, '100%')]
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print('--- duty sweep: 4 s per step, watch the scope')
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for sar, label in steps:
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m[SAR_OFF:SAR_OFF + 4] = struct.pack('<I', sar)
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time.sleep(0.1)
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cur = struct.unpack('<I', m[SAR_OFF:SAR_OFF + 4])[0]
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print(' PWMSAR=%-3d (%s of %d counts) readback=%d' % (sar, label, period, cur))
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time.sleep(4)
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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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print('--- safety readback (after)')
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safety_readback()
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dump_regs(m)
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m.close()
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