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notes_88pa.md

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LED Badge

Speed = 12,000,000
Target Frame Rate = 30

Segments = 24
Pixels per Segment = 24
Brightness Passes = 8 # this is with the 1, 4, 8 gamma spread

Frame Width = 48
Frame Height = 12
Pixels = Frame Width * Frame Height => 576
Pixel Blocks = floor((Frame Width + 7) / 8) * Frame Height => 72
Padded Pixels = Pixel Blocks * 8 => 576

Bits per Pixel Compressed = 2 bits
Bits per Pixel Uncompressed = 3 bits
Pixels per Byte Compressed = 8 bits / Bits per Pixel Compressed  => 4
Pixels per Byte Uncompressed = 8 bits / Bits per Pixel Uncompressed => 2.6667

Bytes per Frame Compressed = Pixels / Pixels per Byte Compressed in bytes => 144 bytes
Bytes per Frame Uncompressed = Pixels / Pixels per Byte Uncompressed in bytes => 216 bytes

Measured Segment Cycles = 248 # measured
Refresh Interval = 336
Refresh Rate = Speed / Refresh Interval / Segments / Brightness Passes => 186.0119

Cycles Left Over = Speed * ((Refresh Interval - Measured Segment Cycles) / Refresh Interval) => 3,142,857.1429
Cycles per Frame = Cycles Left Over / Target Frame Rate => 104,761.9048
Cycles per Pixel = Cycles per Frame / Pixels => 181.8783
Cycle Ratio = Cycles Left Over / Speed => 0.2619

Measured SetPixBlock Cycles = 38
Measured GetPixBlock Cycles = 34
Measured ClearBuffer Cycles = 1088
Measured SolidFill Cycles = 2148
Measured Fill Cycles = 7062
Measured Copy Cycles = 2641

Est Cycles per Fill = Pixel Blocks * Measured SetPixBlock Cycles => 2,736
Est Cycles per Copy = Pixel Blocks * (Measured GetPixBlock Cycles + Measured SetPixBlock Cycles) => 5,184

Est Longest Op = Measured Fill Cycles / Cycle Ratio => 26,964
Fills per Frame = Cycles per Frame / Measured Fill Cycles => 14.8346
Copies per Frame = Cycles per Frame / Measured Copy Cycles => 39.6675

Bandwidth

Video Bandwidth = Target Frame Rate * Bytes per Frame Compressed => 4,320 bytes
Command Bandwidth = Target Frame Rate * 6 in bytes => 180 bytes
Bandwidth = Video Bandwidth + Command Bandwidth => 4,500 bytes
Bits Per Baud = 1 + 8 + 1
Min Baud = Bandwidth * (Bits Per Baud / 8) / sec in baud => 45,000 baud
Baud = 57600

Bytes per Frame = (Baud / Bits Per Baud) / Target Frame Rate => 192
Cycles per Byte = Speed / (Baud / Bits Per Baud) => 2,083.3333
Queue Size = Est Longest Op / Cycles per Byte => 12.9427

UBBR(Baud) = Speed / (16 * Baud) - 1
Selected UBBR = UBBR(Baud) => 12.0208
Selected Rounded UBBR = round(Selected UBBR) => 12
1 - (Selected UBBR / Selected Rounded UBBR) in percent => -0.1736%

I2C Bandwidth

I2C Bandwidth = 200000
I2C Bytes per Page = 8
I2C Page Read Overhead = 20
I2C Pages per Second = I2C Bandwidth / ((8 + 1) * I2C Bytes per Page + I2C Page Read Overhead) => 2,173.913
I2C Bytes per Second = I2C Pages per Second * I2C Bytes per Page => 17,391.3043
I2C Bytes per Frame = I2C Bytes per Second / Target Frame Rate => 579.7101
I2C Frames per Frame = (I2C Bytes per Frame in bytes) / Bytes per Frame Compressed => 4.0258

I2C TWBR Value = ((Speed / I2C Bandwidth) - 16) / 1 / 2 => 22
Speed / (16 + 2*I2C TWBR Value*1) => 200,000