SlowerFire SoC

Perhaps you've heard of PolarFire Soc by Microchip.  It's a very capable Risc-V SoC with an FPGA component, but it will set you back nearly $500.

If you don't have that kind of cash and don't think you need the superior capabilities of that system, I present "SlowerFire SoC". The "SlowerFire Soc" is based on the DE0-Nano Altera Cyclone IV board that is loaded with the Linux-on-Litex-Vexriscv bits.

There are five components

• FPGA Bits
• Linux-on-Litex-Vexriscv "emulator"
• Device Tree blob
• Kernel Image
• Initrd root filesystem

Parts List:

• DE0-Nano at Digikey
• ENC28J60 BOARD at Digikey
• FTDI Serial at Digikey

DE0 Connections:

• SPI Serial flash is SF_xxxx
• I2C SEEPROM is at I2C_xxx
• Serial is at SERIAL_xx
• ENC28J60 is at E_xxxx
• eclk25 is a 25MHz clock (for the ENC28J60 if it doesn't have an onboard clock)

GPIO_1	FPGA PIN	Description
_10	F13	SERIAL_RX
_11	T15	SERIAL_TX
_13	T13	SF CSN
_15	T12	SF MISO
_17	T11	SF MOSI
GND	--	GND
_19	R11	SF CLK
_111	R10
_113	P9
_115	N11
_117	K16	E RST
_119	L15	I2C SCL
_121	P16	I2C SDA
_123	N16	E CSN(LED0)
GND	--	GND
_125	P14	E CLK
_127	N14	E MOSI
_129	L13	E MISO
_131	K15	E INT
_133	J14	eclk25

Follow the Linux-on-LiteX-Vexrsicv instruction to boot system

Login is root/root

Features & Specifications

• PolarFire SoC (MPFS250T-FCVG484EES)SlowerFire
  • 600 50 MHz clock
  • 1 x RV64IMAC core by SiFive RV32I core by VexRiscv
  • 4 x RV64GC core by SiFive
  • 254K  22K (14.6K remaining) logic elements non-volatile fabric
  • 784 132x math block (18 x 18) (9x9)
  • 4 x 12.7 Gbps SERDES
  • Secure boot
• Memory
  • 2 GB LPDDR4 x 32 32MB SDRAM x16
• Storage
  • 1 Gb 16 MB SPI flash
  • 8 GB eMMC flash or SD card slot (multiplexed)
• Networking
  • 2 x Gigabit  1x 10/100 Ethernet (runs about 350kb/s)
• Expansion Interfaces
  • Raspberry Pi-compatible 40-pin header
  • mikroBUS socket
  • PCIe gen2
  • Micro USB 2.0 Hi-Speed OTG
  • 4 1 x UART (via TTL single micro USB)
  • 2 x CAN
  • SPI
  • I²C
• Power
  • 12 5 VDC / 1A Mini-USB  5 A barrel jack input
  • On/off switch
  • I²C power monitor measuring four power rails
• User Interfaces
  • 4 x User push button
  • 4 3 x User LED
  • 4 x Power status LED
• Programming & Debugging
  • UART via micro USB
  • Onboard JTAG connector or embedded FlashPro6 (multiplexed)
  • 52 x test points

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