  YiFive A1 SOC


Permission to use, copy, modify, and/or distribute this soc for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOC IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOC INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOC.

Overview

YiFive is a 32 bit RISC V based SOC design targeted for efabless Shuttle program. This project uses only open source tool set for simulation,synthesis and backend tools. The SOC flow follow the openlane methodology and SOC environment is compatible with efabless/carvel methodology.

YiFive Block Diagram

Key features

    * Open sourced under Apache-2.0 License (see LICENSE file) - unrestricted commercial use allowed.
    * industry-grade and silicon-proven Open-Source RISC-V core from syntacore 
    * industry-graded and silicon-proven 8-bit SDRAM controller
    * Quad SPI Master
    * UART with 16Byte FIFO
    * I2C Master
    * Wishbone compatible design
    * Written in System Verilog
    * Open-source tool set
       * simulation - iverilog
       * synthesis  - yosys
       * backend/sta - openlane tool set
    * Verification suite provided.

Sub IP features

RISC V Core

YiFive SOC Integrated Syntacore SCR1 Open-source RISV-V compatible MCU-class core. It is industry-grade and silicon-proven IP. Git link: https://github.com/syntacore/scr1

Block Diagram

RISC V Core Key feature

   * RV32I or RV32E ISA base + optional RVM and RVC standard extensions
   * Machine privilege mode only
   * 2 to 4 stage pipeline
   * Optional Integrated Programmable Interrupt Controller with 16 IRQ lines
   * Optional RISC-V Debug subsystem with JTAG interface
   * Optional on-chip Tightly-Coupled Memory

RISC V core customization YiFive SOC

Update: Modified some of the system verilog syntax to basic verilog syntax to compile/synthesis in open source tool like simulator (iverilog) and synthesis (yosys).
Modification: Modified the AXI/AHB interface to wishbone interface towards instruction & data memory interface

8bit SDRAM Controller

Due to number of pin limitation in carvel shuttle, YiFive SOC integrate 8bit SDRAM controller. This is a silicon proven IP. IP Link: https://opencores.org/projects/sdr_ctrl

Block Diagram

SDRAM Controller key Feature

    * 8/16/32 Configurable SDRAM data width
    * Wish Bone compatible
    * Application clock and SDRAM clock can be async
    * Programmable column address
    * Support for industry-standard SDRAM devices and modules
    * Supports all standard SDRAM functions.
    * Fully Synchronous; All signals registered on positive edge of system clock.
    * One chip-select signals
    * Support SDRAM with four banks
    * Programmable CAS latency
    * Data mask signals for partial write operations
    * Bank management architecture, which minimizes latency.
    * Automatic controlled refresh

SOC Memory Map

RISC IMEM	RISC DMEM	EXT MAP	Target IP
0x0000_0000 to 0x0FFF_FFFF	0x0000_0000 to 0x0FFF_FFFF	0x4000_0000 to 0x4FFF_FFFF	SPI FLASH MEMORY
0x1000_0000 to 0x1000_00FF	0x1000_0000 to 0x1000_00FF	0x5000_0000 to 0x5000_00FF	SPI Config Reg
0x2000_0000 to 0x2FFF_FFFF	0x2000_0000 to 0x2FFF_FFFF	0x6000_0000 to 0x6FFF_FFFF	SDRAM
0x3000_0000 to 0x3000_00FF	0x3000_0000 to 0x3000_00FF	0x3000_0000 to 0x3000_00FF	Global Register

SOC Size

Block	Total Cell	Seq	Combo
RISC	26642	3158	23484
GLOBAL REG	2753	575	2178
SDRAM	7198	1207	5991
SPI	7607	1279	6328
UART_I2C	3561	605	2956
WB_HOST	3073	515	2558
WB_INTC	1291	110	1181

TOTAL	52125	7449	44676

SOC Register Map

Register Map: Wishbone HOST

Offset	Name	Description
0x00	GLBL_CTRL	[RW] Global Wishbone Access Control Register
0x04	BANK_CTRL	[RW] Bank Selection, MSB 8 bit Address
0x08	CLK_SKEW_CTRL1	[RW] Clock Skew Control2
0x0c	CLK_SKEW_CTRL2	[RW] Clock Skew Control2

Register: GLBL_CTRL

Bits	Name	Description
31:24	Resevered	Unsused
23:20	RTC_CLK_CTRL	RTC Clock Div Selection
19:16	CPU_CLK_CTRL	CPU Clock Div Selection
15:12	SDARM_CLK_CTRL	SDRAM Clock Div Selection
10:8	WB_CLK_CTRL	Core Wishbone Clock Div Selection
7	UART_I2C_SEL	0 - UART , 1 - I2C Master IO Selection
5	I2C_RST	I2C Reset Control
4	UART_RST	UART Reset Control
3	SDRAM_RST	SDRAM Reset Control
2	SPI_RST	SPI Reset Control
1	CPU_RST	CPU Reset Control
0	WB_RST	Wishbone Core Reset Control

Register: BANK_CTRL

Bits	Name	Description
31:24	Resevered	Unsused
7:0	BANK_SEL	Holds the upper 8 bit address core Wishbone Address

Register: CLK_SKEW_CTRL1

Bits	Name	Description
31:28	Resevered	Unsused
27:24	CLK_SKEW_WB	WishBone Core Clk Skew Control
23:20	CLK_SKEW_GLBL	Glbal Register Clk Skew Control
19:16	CLK_SKEW_SDRAM	SDRAM Clk Skew Control
15:12	CLK_SKEW_SPI	SPI Clk Skew Control
11:8	CLK_SKEW_UART	UART/I2C Clk Skew Control
7:4	CLK_SKEW_RISC	RISC Clk Skew Control
3:0	CLK_SKEW_WI	Wishbone Clk Skew Control

Register Map: SPI MASTER

Offset	Name	Description
0x00	GLBL_CTRL	[RW] Global SPI Access Control Register
0x04	DMEM_CTRL1	[RW] Direct SPI Memory Access Control Register1
0x08	DMEM_CTRL2	[RW] Direct SPI Memory Access Control Register2
0x0c	IMEM_CTRL1	[RW] Indirect SPI Memory Access Control Register1
0x10	IMEM_CTRL2	[RW] Indirect SPI Memory Access Control Register2
0x14	IMEM_ADDR	[RW] Indirect SPI Memory Address
0x18	IMEM_WDATA	[W] Indirect SPI Memory Write Data
0x1c	IMEM_RDATA	[R] Indirect SPI Memory Read Data
0x20	SPI_STATUS	[R] SPI Debug Status

Register: GLBL_CTRL

Bits	Name	Description
31:16	Resevered	Unsused
15:8	SPI_CLK_DIV	SPI Clock Div Rato Selection
7:4	Reserved	Unused
3:2	CS_LATE	CS DE_ASSERTION CONTROL
1:0	CS_EARLY	CS ASSERTION CONTROL

Register: DMEM_CTRL1

Bits	Name	Description
31:9	Resevered	Unsused
8	FSM_RST	Direct Mem State Machine Reset
7:6	SPI_SWITCH	Phase at which SPI Mode need to switch
5:4	SPI_MODE	SPI Mode, 0 - Single, 1 - Dual, 2 - Quad, 3 - QDDR
3:0	CS_SELECT	CHIP SELECT

Register: DMEM_CTRL2

Bits	Name	Description
31:24	DATA_CNT	Total Data Byte Count
23:22	DUMMY_CNT	Total Dummy Byte Count
21:20	ADDR_CNT	Total Address Byte Count
19:16	SPI_SEQ	SPI Access Sequence
15:8	MODE_REG	Mode Register Value
7:0	CMD_REG	Command Register Value

Register: IMEM_CTRL1

Bits	Name	Description
31:9	Resevered	Unsused
8	FSM_RST	InDirect Mem State Machine Reset
7:6	SPI_SWITCH	Phase at which SPI Mode need to switch
5:4	SPI_MODE	SPI Mode, 0 - Single, 1 - Dual, 2 - Quad, 3 - QDDR
3:0	CS_SELECT	CHIP SELECT

Register: IMEM_CTRL2

Bits	Name	Description
31:24	DATA_CNT	Total Data Byte Count
23:22	DUMMY_CNT	Total Dummy Byte Count
21:20	ADDR_CNT	Total Address Byte Count
19:16	SPI_SEQ	SPI Access Sequence
15:8	MODE_REG	Mode Register Value
7:0	CMD_REG	Command Register Value

Register: IMEM_ADDR

Bits	Name	Description
31:0	ADDR	Indirect Memory Address

Register: IMEM_WDATA

Bits	Name	Description
31:0	WDATA	Indirect Memory Write Data

Register: IMEM_RDATA

Bits	Name	Description
31:0	RDATA	Indirect Memory Read Data

Register: SPI_STATUS

Bits	Name	Description
31:0	DEBUG	SPI Debug Status

Register Map: Global Register

Offset	Name	Description
0x00	SOFT_REG0	[RW] Software Register0
0x04	RISC_FUSE	[RW] Risc Fuse Value
0x08	SOFT_REG2	[RW] Software Register2
0x0c	INTR_CTRL	[RW] Interrupt Control
0x10	SDRAM_CTRL1	[RW] Indirect SPI Memory Access Control Register2
0x14	SDRAM_CTRL2	[RW] Indirect SPI Memory Address
0x18	SOFT_REG6	[RW] Software Register6
0x1C	SOFT_REG7	[RW] Software Register7
0x20	SOFT_REG8	[RW] Software Register8
0x24	SOFT_REG9	[RW] Software Register9
0x28	SOFT_REG10	[RW] Software Register10
0x2C	SOFT_REG11	[RW] Software Register11
0x30	SOFT_REG12	[RW] Software Register12
0x34	SOFT_REG13	[RW] Software Register13
0x38	SOFT_REG14	[RW] Software Register14
0x3C	SOFT_REG15	[RW] Software Register15

Register: RISC_FUSE

Bits	Name	Description
31:0	RISC_FUSE	RISC Core Fuse Value

Register: INTR_CTRL

Bits	Name	Description
31:20	Reserved	Unused
19:17	USER_IRQ	User Interrupt generation toward riscv
16	SOFT_IRQ	Software Interrupt generation toward riscv
15:0	EXT_IRQ	External Interrupt generation toward riscv

Register: SDRAM_CTRL1

Bits	Name	Description
31	Reserved	Unused
30	SDRAM_INIT_DONE	SDRAM init done indication
29	SDR_EN	SDRAM controller enable
28:26	SDR_CAS	SDRAM CAS latency
25:24	SDR_REQ_DP	SDRAM Maximum Request accepted by SDRAM controller
23:20	SDR_TWR	SDRAM Write Recovery delay
19:16	SDR_TRCAR	SDRAM Auto Refresh Period
15:12	SDR_TRCD	SDRAM Active ti R/W delay
11:8	SDR_TRP	SDRAM Prechard to active delay
7:4	SDR_TRAS	SDRAM Active to precharge
3:2	SDR_COL	SDRAM Colum Address
1:0	SDR_WD	SDRAM Interface Width, 0 - 32bit, 1 - 16 bit, 2 - 8 bit

Register: SDRAM_CTRL2

Bits	Name	Description
31:28	Reserved	Unused
27:16	SDRAM_REFRESH	SDRAM Refresh Rate per row
15:3	SDR_MODE_REG	SDRAM Mode Register
2:0	SDR_MODE_REG	Number of rows to rfsh at a time

SOC Pin Mapping

Carvel SOC provides 38 GPIO pins for user functionality. YiFive SOC GPIO Pin Mapping as follows

GPIO Pin Number	Direction	Pad Name	Block Name
gpio[7:0]	Inout	SDRAM Data [7:0]	SDRAM
gpio[20:8]	Output	SDRAM Address [12:0]	SDRAM
gpio[22:21]	Output	SDRAM Bank Select [1:0]	SDRAM
gpio[23]	Output	SDRAM Byte Mask	SDRAM
gpio[24]	Output	SDRAM Write Enable	SDRAM
gpio[25]	Output	SDRAM CAS	SDRAM
gpio[26]	Output	SDRAM RAS	SDRAM
gpio[27]	Output	SDRAM Chip Select	SDRAM
gpio[28]	Output	SDRAM CKE	SDRAM
gpio[29]	Inout	SDRAM Clock	SDRAM
gpio[30]	Output	SPI Clock	SPI
gpio[31]	Output	SPI Chip Select	SPI
gpio[35:32]	Inout	SPI Data	SPI
gpio[36]	Inout	Uart TX/I2C CLK	UART/I2C
gpio[37]	Inout	Uart RX/I2C Data	UART/I2C

Repository contents

|verilog
|   ├─  rtl
|   |     |-  syntacore
|   |     |     |─  scr1
|   |     |     |    ├─ **docs**                           | **SCR1 documentation**
|   |     |     |    |      ├─ scr1_eas.pdf                | SCR1 External Architecture Specification
|   |     |     |    |      └─ scr1_um.pdf                 | SCR1 User Manual
|   |     |     |    |─  **src**                           | **SCR1 RTL source and testbench files**
|   |     |     |    |   ├─ includes                       | Header files
|   |     |     |    |   ├─ core                           | Core top source files
|   |     |     |    |   ├─ top                            | Cluster source files
|   |     |     |    |─  **synth**                         | **SCR1 RTL Synthesis files **
|   |     |- sdram_ctrl
|   |     |     |- **src**
|   |     |     |   |- **docs**                            | **SDRAM Controller Documentation**
|   |     |     |   |     |- sdram_controller_specs.pdf    | SDRAM Controller Design Specification
|   |     |     |   |             
|   |     |     |   |- core                                | SDRAM Core integration source files                          
|   |     |     |   |- defs                                | SDRAM Core defines
|   |     |     |   |- top                                 | SDRAM Top integration source files
|   |     |     |   |- wb2sdrc                             | SDRAM Wishbone source files
|   |     |- spi_master
|   |     |     |- src                                     | Qard SPI Master Source files
|   |     |-wb_interconnect
|   |     |     |- src                                     | 3x4 Wishbone Interconnect
|   |     |- digital_core
|   |     |     |- src                                     | Digital core Source files
|   |     |- lib                                           | common library source files
|   |- dv
|   |   |- la_test1                                        | carevel LA test
|   |   |- risc_boot                                       | user core risc boot test
|   |   |- wb_port                                         | user wishbone test
|   |   |- user_risc_boot                                  | user standalone test without carevel soc
|   |- gl                                                  | ** GLS Source files **
|
|- openlane
    |- sdram                                               | sdram openlane scripts   
    |- spi_master                                          | spi_master openlane scripts   
    |- syntacore                                           | Risc Core openlane scripts   
    |- yifive                                              | yifive digital core openlane scripts
    |- user_project_wrapper                                | carvel user project wrapper

Prerequisites

Docker (ensure docker daemon is running) -- tested with version 19.03.12, but any recent version should suffice.

Environment setting

Note: PDK alreay installed inside the docker, no need to define the PDK_ROOT, This will be point to /opt/pdk path inside the docker if user define the PDK_ROOT path, then flow will use the user defined PDK PATH

    export CARAVEL_ROOT=<Carvel Installed Path>
    export OPENLANE_ROOT=<OpenLane Installed Path>
    export IMAGE_NAME=dineshannayya/openlane:rc7

Tests preparation

The simulation package includes the following tests:

risc_boot - Simple User Risc core boot
wb_port - User Wishbone validation
user_risc_boot - Standalone User Risc core boot

Running Simulation

Examples:

    make verify-wb_port  
    make verify-risc_boot
    make verify-user_uart
    make verify-user_spi
    make verify-user_i2cm
    make verify-user_risc_boot

Tool Sets

YiFive Soc flow uses Openlane tool sets.

Synthesis
1. yosys - Performs RTL synthesis
2. abc - Performs technology mapping
3. OpenSTA - Pefroms static timing analysis on the resulting netlist to generate timing reports
Floorplan and PDN
1. init_fp - Defines the core area for the macro as well as the rows (used for placement) and the tracks (used for routing)
2. ioplacer - Places the macro input and output ports
3. pdn - Generates the power distribution network
4. tapcell - Inserts welltap and decap cells in the floorplan
Placement
1. RePLace - Performs global placement
2. Resizer - Performs optional optimizations on the design
3. OpenPhySyn - Performs timing optimizations on the design
4. OpenDP - Perfroms detailed placement to legalize the globally placed components
CTS
1. TritonCTS - Synthesizes the clock distribution network (the clock tree)
Routing
1. FastRoute - Performs global routing to generate a guide file for the detailed router
2. CU-GR - Another option for performing global routing.
3. TritonRoute - Performs detailed routing
4. SPEF-Extractor - Performs SPEF extraction
GDSII Generation
1. Magic - Streams out the final GDSII layout file from the routed def
2. Klayout - Streams out the final GDSII layout file from the routed def as a back-up
Checks
1. Magic - Performs DRC Checks & Antenna Checks
2. Klayout - Performs DRC Checks
3. Netgen - Performs LVS Checks
4. CVC - Performs Circuit Validity Checks

important Note

Following tools in openlane docker is older version, we need to update these tool set.

Icarus Verilog version 12.0 (devel) (s20150603-1107-ga446c34d)
Yosys 0.9+4081 (git sha1 b6721aa9, clang 10.0.0-4ubuntu1 -fPIC -Os)

We have modified these openlane changes in our git repo, you can use from these path git clone https://github.com/dineshannayya/openlane.git docker pull dineshannayya/openlane:rc7

Contacts

Report an issue: https://github.com/dineshannayya/yifive_r0/issues

Documentation

Syntacore Link - https://github.com/syntacore/scr1
SDRAM Controller - https://opencores.org/projects/sdr_ctrl

Name		Name	Last commit message	Last commit date
Latest commit History 104 Commits
caravel @ ff960da		caravel @ ff960da
checks		checks
def		def
docs/source/_static		docs/source/_static
gds		gds
lef		lef
mag		mag
maglef		maglef
openlane		openlane
signoff		signoff
spef		spef
spi/lvs		spi/lvs
sta		sta
verilog		verilog
.gitmodules		.gitmodules
LICENSE		LICENSE
Makefile		Makefile
README.md		README.md
info.yaml		info.yaml

License

dineshannayya/yifive_r0

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Table of contents

Overview

YiFive Block Diagram

Key features

Sub IP features

RISC V Core

Block Diagram

RISC V Core Key feature

RISC V core customization YiFive SOC

8bit SDRAM Controller

Block Diagram

SDRAM Controller key Feature

SOC Memory Map

SOC Size

SOC Register Map

Register Map: Wishbone HOST

Register: GLBL_CTRL

Register: BANK_CTRL

Register: CLK_SKEW_CTRL1

Register Map: SPI MASTER

Register: GLBL_CTRL

Register: DMEM_CTRL1

Register: DMEM_CTRL2

Register: IMEM_CTRL1

Register: IMEM_CTRL2

Register: IMEM_ADDR

Register: IMEM_WDATA

Register: IMEM_RDATA

Register: SPI_STATUS

Register Map: Global Register

Register: RISC_FUSE

Register: INTR_CTRL

Register: SDRAM_CTRL1

Register: SDRAM_CTRL2

SOC Pin Mapping

Repository contents

Prerequisites

Environment setting

Tests preparation

Running Simulation

Tool Sets

important Note

Contacts

Documentation

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