FIFO Design
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The document describes the design of a FIFO (first-in first-out) buffer. It explains the FIFO interface, protocol, datapath and control path. The FIFO uses a read and write pointer to control reading and writing of data to an internal memory buffer. Status signals like full and empty are generated by comparing the read and write pointers. The design aims to ensure reliable operation by following the specified protocol of not allowing a write when full or a read when empty.
FIFO Design
- 1. FIFO Design Aditya Mittal
- 2. Objective • Use Design Framework • Request/Grant Handshake • Valid/Busy Handshake © Arrow Devices Pvt. Ltd. 2
- 3. FIFO Interface © Arrow Devices Pvt. Ltd. 3
- 4. FIFO Protocol • FIFO not guaranteed to work if protocol violated • Write Data qualified by Push • Read Data validated by !Empty • Should not Push when Full • Should not Pop when Empty © Arrow Devices Pvt. Ltd. 4
- 5. FIFO Protocol © Arrow Devices Pvt. Ltd. 5
- 6. FIFO Datapath • Input Data (bus) • Output Data (bus) • Data Store (memory /flop array) © Arrow Devices Pvt. Ltd. 6
- 7. FIFO Datapath © Arrow Devices Pvt. Ltd. 7
- 8. FIFO Control Path • Data Path Control – Write Control – Read Control • Flow Control © Arrow Devices Pvt. Ltd. 8
- 9. FIFO Write Control • Write Pointer: Next memory address to write • Convention: Push causes write pointer to move to next location • Decode of write pointer enables memory locations © Arrow Devices Pvt. Ltd. 9
- 10. FIFO Read Control • Read Pointer: Next memory address to read • Convention: Pop causes read pointer to move to next location © Arrow Devices Pvt. Ltd. 10
- 11. FIFO Read/Write © Arrow Devices Pvt. Ltd. 11
- 12. FIFO Flow Control • Write Interface: Full signal • Read Interface: Empty signal © Arrow Devices Pvt. Ltd. 12
- 13. © Arrow Devices Pvt. Ltd. 13
- 14. FIFO Full Generation • Full Condition: Both pointers are pointing to same location © Arrow Devices Pvt. Ltd. 14
- 15. FIFO Empty Generation • Empty Condition: Both pointers are pointing to same location © Arrow Devices Pvt. Ltd. 15
- 16. Pointer Wrap State • Set wrap bit every time pointer “wraps around” the max value © Arrow Devices Pvt. Ltd. 16
- 17. FIFO Full/Empty Conditions • Full when pointer values are same and wrap states are different • Empty when pointer values are same and wrap states are same © Arrow Devices Pvt. Ltd. 17