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Timing
John McMaster edited this page Feb 28, 2018
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Notes on creating a device timing model
Fanout effect timing info. IIRC I saw about 20% variation across things
The following fields are consistent across wire name (ie L/R doesn't effect):
- COST_CODE
- IS_INPUT_PIN
- IS_OUTPUT_PIN
- IS_PART_OF_BUS
- NUM_INTERSECTS
- NUM_TILE_PORTS
- SPEED_INDEX
- TILE_PATTERN_OFFSET
The following vary:
- ID_IN_TILE_TYPE
- IS_CONNECTED
- NUM_DOWNHILL_PIPS
- NUM_PIPS
- NUM_UPHILL_PIPS
- TILE_NAME
The following fields are consistent across wire name (ie L/R doesn't effect):
- COST_CODE
- COST_CODE_NAME
- IS_BAD
- IS_COMPLETE
- IS_GND
- IS_VCC
The following vary:
- SPEED_CLASS
- IS_PIN
- IS_INPUT_PIN
- IS_OUTPUT_PIN
- PIN_WIRE
- NUM_WIRES
PIN_WIRE: sometimes 65535
SPEED_CLASS shifts around a lot depending on other parameter values, which also shift around. A few interesting comparisons
Sometimes it differs for no apparent reason. For example:
- BASE_CLOCK_REGION:X0Y3 CLASS:node COST_CODE:21 COST_CODE_NAME:HQUAD IS_BAD:0 IS_COMPLETE:1 IS_GND:0 IS_INPUT_PIN:0 IS_OUTPUT_PIN:0 IS_PIN:0 IS_VCC:0 NAME:INT_L_X0Y199/WW4BEG3 NUM_WIRES:13 PIN_WIRE:65535 SPEED_CLASS:100
- BASE_CLOCK_REGION:X0Y3 CLASS:node COST_CODE:21 COST_CODE_NAME:HQUAD IS_BAD:0 IS_COMPLETE:1 IS_GND:0 IS_INPUT_PIN:0 IS_OUTPUT_PIN:0 IS_PIN:0 IS_VCC:0 NAME:INT_L_X2Y199/WW4BEG3 NUM_WIRES:13 PIN_WIRE:65535 SPEED_CLASS:284