Roflin
a082e15c4f
First silicon proof of the EXI capture path. A Pi bit-banging EXI into J4 reads the device ID 04 02 02 00 21/21, NWAYS 0x17, HIPR 0x01, writes and reads back PAR0-3, writes IMR, and sees NCRA's reset bit self-clear. Fixes two host-side bugs found getting there: - exi_devid_rpi.py sampled MISO just after the rising edge, racing the slave's own update and landing one bit early (04 came back as 08). Sample in the CLK-low phase, as the simulation does. - pi-exi-wirecheck.py's bridge scan drove HIGH against pull-downs, but the FPGA's SB_IO pull-up out-pulls the Pi's internal pull-down, so every pin reported as bridged. The aggressor now drives LOW against pull-ups. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
48 lines
1.7 KiB
Python
48 lines
1.7 KiB
Python
#!/usr/bin/env python3
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"""Clock EXACTLY the requested byte count, the way the GC driver does."""
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import time, collections
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import RPi.GPIO as GPIO
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CLK, MOSI, MISO, CS = 11, 10, 9, 8
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GPIO.setmode(GPIO.BCM); GPIO.setwarnings(False)
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GPIO.setup(CLK, GPIO.OUT, initial=1); GPIO.setup(MOSI, GPIO.OUT, initial=0)
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GPIO.setup(CS, GPIO.OUT, initial=1); GPIO.setup(MISO, GPIO.IN)
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def xfer(b):
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r = 0
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for i in range(7, -1, -1):
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GPIO.output(MOSI, (b >> i) & 1)
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GPIO.output(CLK, 0)
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r = (r << 1) | GPIO.input(MISO)
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GPIO.output(CLK, 1)
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return r
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def read(addr, n, gap=0.005, idle=0.010):
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GPIO.output(CS, 0); GPIO.output(CLK, 1); time.sleep(0.0005)
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xfer((addr >> 6) & 0x7F); xfer(((addr & 0x3F) << 2) | ((n - 1) & 3))
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time.sleep(gap)
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out = [xfer(0x00) for _ in range(n)] # EXACTLY n bytes, no more
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GPIO.output(CS, 1); time.sleep(idle)
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return out
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def trial(tag, addr, n, want, reps=21, idle=0.010):
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hits = collections.Counter(); ok = 0
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seq = []
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for _ in range(reps):
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r = read(addr, n, idle=idle)
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hits[" ".join("%02x" % x for x in r)] += 1
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good = r == want
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ok += good
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seq.append("." if good else "x")
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print(f" {tag:<34} {ok:>2}/{reps} {''.join(seq)}")
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for pat, cnt in hits.most_common(3):
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print(f" {cnt:>3}x {pat}")
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print("=== exact-length reads, 10ms idle between transactions ===")
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trial("device ID @0x0000 (4B)", 0x0000, 4, [0x04, 0x02, 0x02, 0x00])
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trial("NWAYS @0x31 (1B)", 0x31, 1, [0x17])
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trial("HIPR @0x3A (1B)", 0x3A, 1, [0x01])
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print()
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print("=== same, but 200ms idle (does state decay?) ===")
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trial("device ID @0x0000 (4B)", 0x0000, 4, [0x04, 0x02, 0x02, 0x00], reps=9, idle=0.200)
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GPIO.cleanup()
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