Merge pull request #3077 from adafruit/TheKitty-patch-7
Update Find_EDID_Values.py
This commit is contained in:
Anne Barela
GitHub
commit
e579992b2f
1 changed files with 37 additions and 31 deletions
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@ -6,12 +6,14 @@
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#
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import sys
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import board
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import busio
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import busio
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def parse_established_timings(edid):
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# pylint: disable=redefined-outer-name
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# pylint: disable=too-many-branches
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"""Parse established timings from EDID bytes 35-37"""
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modes = []
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# Byte 35 (established timings I)
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if edid[35] & 0x80:
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modes.append("720x400 @70Hz")
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@ -29,7 +31,7 @@ def parse_established_timings(edid):
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modes.append("800x600 @56Hz")
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if edid[35] & 0x01:
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modes.append("800x600 @60Hz")
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# Byte 36 (established timings II)
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if edid[36] & 0x80:
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modes.append("800x600 @72Hz")
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@ -47,31 +49,32 @@ def parse_established_timings(edid):
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modes.append("1024x768 @75Hz")
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if edid[36] & 0x01:
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modes.append("1280x1024 @75Hz")
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# Byte 37 (manufacturer timings)
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if edid[37] & 0x80:
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modes.append("1152x870 @75Hz")
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return modes
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def parse_standard_timings(edid):
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# pylint: disable=redefined-outer-name
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"""Parse standard timings from EDID bytes 38-53"""
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modes = []
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for i in range(38, 54, 2): # 8 standard timing descriptors, 2 bytes each
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if edid[i] == 0x01 and edid[i+1] == 0x01:
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continue # Unused timing
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if edid[i] == 0x00:
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continue # Invalid timing
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# Calculate horizontal resolution
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h_res = (edid[i] + 31) * 8
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# Calculate aspect ratio and vertical resolution
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aspect_ratio = (edid[i+1] & 0xC0) >> 6
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refresh_rate = (edid[i+1] & 0x3F) + 60
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if aspect_ratio == 0: # 16:10
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aspect = "16:10"
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v_res = (h_res * 10) // 16
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@ -84,92 +87,95 @@ def parse_standard_timings(edid):
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else: # aspect_ratio == 3, 16:9
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aspect = "16:9"
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v_res = (h_res * 9) // 16
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modes.append(f"{h_res}x{v_res} @{refresh_rate}Hz, Aspect: {aspect}")
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return modes
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def parse_detailed_timings(edid):
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# pylint: disable=redefined-outer-name
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# pylint: disable=unused-variable
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# pylint: disable=too-many-locals
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"""Parse detailed timing descriptors from EDID bytes 54-125"""
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modes = []
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for i in range(54, 126, 18): # 4 detailed timing descriptors, 18 bytes each
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# Check if this is a timing descriptor (pixel clock != 0)
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pixel_clock = edid[i] | (edid[i+1] << 8)
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if pixel_clock == 0:
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continue # Not a timing descriptor
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# Parse horizontal resolution
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h_active_low = edid[i+2]
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h_active_high = (edid[i+4] & 0xF0) >> 4
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h_active = h_active_low | (h_active_high << 8)
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# Parse vertical resolution
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v_active_low = edid[i+5]
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v_active_high = (edid[i+7] & 0xF0) >> 4
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v_active = v_active_low | (v_active_high << 8)
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# Parse horizontal sync
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h_sync_offset_low = edid[i+8]
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h_sync_width_low = edid[i+9]
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h_sync_high = (edid[i+11] & 0xC0) >> 6
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h_sync_offset = h_sync_offset_low | ((h_sync_high & 0x3) << 8)
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h_sync_width = h_sync_width_low | ((h_sync_high & 0xC) << 6)
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# Parse vertical sync
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v_sync_offset_low = (edid[i+10] & 0xF0) >> 4
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v_sync_width_low = edid[i+10] & 0x0F
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v_sync_high = (edid[i+11] & 0x0C) >> 2
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v_sync_offset = v_sync_offset_low | ((v_sync_high & 0x3) << 4)
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v_sync_width = v_sync_width_low | ((v_sync_high & 0xC) << 2)
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# Calculate refresh rate (approximate)
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h_blank_low = edid[i+3]
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h_blank_high = edid[i+4] & 0x0F
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h_blank = h_blank_low | (h_blank_high << 8)
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h_total = h_active + h_blank
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v_blank_low = edid[i+6]
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v_blank_high = edid[i+7] & 0x0F
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v_blank = v_blank_low | (v_blank_high << 8)
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v_total = v_active + v_blank
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if h_total > 0 and v_total > 0:
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refresh_rate = (pixel_clock * 10000) // (h_total * v_total)
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modes.append(f"{h_active}x{v_active} @{refresh_rate}Hz")
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return modes
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# Main EDID reading code
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i2c = busio.I2C(board.SCL, board.SDA)
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i2c = busio.I2C(board.SCL, board.SDA)
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if not i2c:
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print("Board doesn't have I2C")
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sys.exit(1)
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if not i2c.try_lock():
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print("Cannot lock I2C")
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sys.exit(1)
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print("\nI2C Present")
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print("\nI2C Present")
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devices = i2c.scan()
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if not (0x50 in devices):
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if not 0x50 in devices:
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print("No device found at EDID address 0x50, is the monitor plugged in " +
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"& board power cycled?")
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sys.exit(1)
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print("Device 0x50 found!")
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device = 0x50
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edid = bytearray(128)
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out = bytearray([0])
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i2c.writeto_then_readfrom(device, out, edid)
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# pylint: disable=too-many-boolean-expressions
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if edid[0] != 0x00 or edid[1] != 0xFF or edid[2] != 0xFF or \
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edid[3] != 0xFF or edid[4] != 0xFF or edid[5] != 0xFF or \
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edid[6] != 0xFF or edid[7] != 0x00:
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print("EDID signature not recognized")
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sys.exit(1)
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print("Valid EDID signature!")
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# Verify checksum
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@ -177,7 +183,7 @@ checksum = sum(edid) & 0xFF
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if checksum != 0:
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print("Bad EDID checksum detected")
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sys.exit(1)
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print("Good EDID checksum!")
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# Parse all supported modes
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@ -187,7 +193,7 @@ supported_modes = []
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established_modes = parse_established_timings(edid)
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supported_modes.extend(established_modes)
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# Get standard timings
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# Get standard timings
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standard_modes = parse_standard_timings(edid)
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supported_modes.extend(standard_modes)
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