(*) Design (VHDL) (*) Verification (System Verilog) Presented by: Omer Shaked Beeri Schreiber The SPI Project

Background - SPI Asynchronous serial data link standard Operates in full duplex mode Devices communicate in master/slave mode the master device initiates the data frame.

Protocol - SPI The master configure the clock polarity and phase with respect to the data

Project Goals 1.Implement SPI Master and SPI Slave 2.Implement SPI Master and Slave Hosts 3.Build Test Benches in System Verilog: A.Individual TB for SPI Master and SPI Slave B.Top TB for the entire system

Implementation Main Problem SPI Clock’s frequency and Polarity may change during runtime. Therefore – SPI Clock cannot be placed in the global nets.

Solution SPI Master and Slave works with the System Clock. Master: SPI Clock is generated from the System Clock, using counter. Slave: SPI Clock (spi_clk) is derivate. SPI Clock Event (MSB = ‘1’) SPI Clock Event (MSB = ‘1’)

Top Architecture Slave Host Slave Host Master Host Master Host Wishbone Slave Interface Wishbone Slave Interface SPI Master Interface SPI Slave Interface RAM Interface RAM

Master Architecture SPI Master SPI Master FIFO Wishbone Slave Controller Wishbone Slave Controller SPI Interface Wishbone Interface Master Host Dec. RAM Enc. RAM M.P. Encoder M.P. Decoder MUX ‘0’ Checksum Implementation for all components is done!

Slave Architecture SPI Slave SPI Slave SPI Interface Message Pack Decoder Message Pack Encoder Type Register Type Register RAM Controller RAM Controller Internal Registers Internal Registers MUX RAM Interface Slave Host RAM Not implemented yet CPOL, CPHA DEC FIFO

Simulations 1.VHDL TB has been performed on RAM, FIFO, Checksum, Message Packs, SPI Master 2.System Verilog TB should be written for the following: A.Individual TB for SPI Master and Slave B.Whole System (Including Wishbone Interface)

Directory Structure 1.All project files are saved to SVN.

Schedule 1.SPI Slave – Slave RAM Controller – Master Host and Slave Connection – Verification schedule is unknown yet.

Verification Plan (1) SPI Master: a.Run with all 4 possible options of CPOL and CPHA. b.Validate that clock is divided correct for minimum and maximum register value. c.FIFO empty (should stop SPI Master transaction). d.Register change during active transaction (Should cause error) e.Operation with single / multiple slaves f.During RESET, change inputs. Validate outputs are in their default value.

Verification Plan (2) SPI Slave: a.Run with all 4 possible options of CPOL and CPHA. b.Negate SPI_SS in the middle of the transaction. c.SPI_CLK stops for a long time (time out). d.Data from RAM is not valid when it should be. e.Register change during active transaction (Should influence after transaction only) f.During RESET, change inputs. Validate outputs are in their default value.

Verification Plan (3) Top Test Bench: a.Run with all 4 possible options of CPOL and CPHA. b.Run with different SPI_CLK frequencies. c.Write data to random address in RAM, then read from it. Validate data match. d.Perform “Write-write-read-write-read”. e.Perform “Write-read-read-write-read”. f.Write Single (burst size of 1), and Burst. g.Write / read to / from non-existing register address. h.Write to valid address, but burst length exceeds from valid address. i.Stop transaction in the middle (Negate WBM_CYC). j.Perform RESET in the middle of the transaction.