SBC V2-005 MEGAFLASH

The SBC V2 is a Zilog Z80 processor board. It's a 100x160mm board that is capable of functioning both as a standalone SBC or as attached to the ECB bus.

The SBC V2-005 is currently under development. See here for the current status.

The main advantage of this version over previous versions is the support of 1Mb FLASH memory and improved software support for Flash access.

Features

  • 4Mhz+ Zilog Z80 CPU.
  • 512Kb paged SRAM.
  • 1Mb Flash ROM.
  • Serial Interface.
  • IDE interface.
  • Real Time Clock.
  • Onboard sound.
  • Battery backup for RTC and SRAM via super capacitor.
  • Standard ECB bus interface.
  • +5V power connector for Single Board Computer operation.
  • Reset button.
  • Recovery mode button.
  • Status LED.
  • Switchable clock speed.

Software Support

ROMWBW BIOS featuring:

  • CP/M / ZSDOS
  • RAM & ROM disk support.
  • ROM based BASIC, FORTH and Monitor.
  • Prebuild disk images

ROMWBW Eurocard expansion board driver support:

  • RAMFLOPPY - Up to 2 x 4Mb memory drives.
  • VDU - Composite VDU monitor and keyboard support.
  • CVDU - Colour VDU and keyboard support.
  • VGA3 - Colour VGA display board and keyboard support
  • Zilog Peripherals - 2xSerial ports, counter timer chip.
  • USB FIFO - USB serial interface
  • Disk I/O - 3.5“, 5-1.4”, 8“ floppy disk and parallel port IDE.
  • 4PIO - Parallel interface card.
  • SCG - Graphics and sound board.
  • DUAL SD CARD - SD Card based memory drive
  • MF-PIC - Colour VGA, keyboard interface.

Pictures

Board

Kicad files can be found here but may not be the most recent.

Gerbers for SBC V2-005c, which have been built and tested. here.

Current revision is SBC V2-005i

Gerbers for SBC V2-005i, currently untested here.

Version i boards are on order as at 27-Feb-2021.

Changes from SBC V2-004

  • Support 2 x 512Mb PLCC style Flash chips for 1Mb Flash memory.
  • Removes support for DIP style Flash and EPROM chips.
  • Removes support for 128Mb RAM
  • Adds switch for recovery mode.
  • Software support for programming dual chips.
  • Driver support for accessing ROM drive as a read and write filesystem.
  • ROMWBW based Flash upgrader.
  • Solder link for UART clock as CPU clock for minimalist system.

Parts List

Reference#Value DIP8DIP14DIP16DIP20DIP32DIP40PLCC32
C1,C3-C23,C29,C30,C32,C33,C35170.1uFCeramic Capacitor
C2110uFElectrolytic Capacitor
C24-C2741uFElectrolytic or Tantalum Capacitor
C28110uFElectrolytic Capacitor
C31122uFElectrolytic Capacitor
C3410.22F+Super Capacitor
D115mm LEDRed/Green Bicolor
D211N4148Diode
K9-K1241×3Pin Header 3 position 2.54mm
JP112×3Pin Header 2×3 position 2.54mm
JP2, LS141×2Pin Header 2 position 2.54mm
P112×2040 pin IDC vertical socket.
P212.1mmBarrel Jack Socket
P312×510 pin IDC vertical socket.
P414/8MhzCPU Clock 5V Active crystal oscillator square socket1
P511.8432MhzUART Clock 5V Active crystal oscillator square
Q112N3906PNP Transistor
SW1, SW226x6mmMini Push Button Switch DIP 4pin
R1110R0.25w resistor
R2,R11210K0.25w resistor
R91100R0.25w resistor
R1214K70.25w resistor
R1313K60.25w resistor
R1411K80.25w resistor
R151120R0.25w resistor
R161470R0.25w resistor
R171100K0.25w resistor
RR1, RR321KSIP-6 Resistor array
RR214K7SIP-6 Resistor array
U1116550UART DIP40 socket 1
U2239SF040Flash 512kb PLCC32 socket 2
U3174LS08Quad 2-in AND Gate DIP14 socket 1
U4174LS10Triple 3-Input NAND Gate DIP14 socket 1
U5174LS125Tri State Quad Bus Buffer DIP14 socket 1
U6174LS139Dual 1-of-4 Decoder/De-multiplexer DIP16 socket 1
U7,U27274LS14Hex Inverter/Schmitt Trigger DIP14 socket 2
U10174LS243Quad Bus Transceiver DIP14 socket 1
U8,U9,U11374LS245Octal tri-state bus transceiver DIP20 socket 3
U12,U13,U18374LS174Hex D-type flip flop with clear DIP16 socket 3
U14-U16374LS32Quad 2-input OR gate DIP14 socket 3
U17174LS244Octal Driver Tri-State DIP20 socket 1
U1918255Programmable Peripheral Interface DIP40 socket 1
U201C96ABCDIN 41612 Connector, 96 pin plug, right angle.
U211DS1302Maxim Trickle-Charge Timekeeping Chip DIP8 socket1
U221MAX232Maxim Multichannel RS-232 Drivers/Receiver DIP16 socket 1
U231AS6C4008512Kb x 8 RAM DIP32 socket 1
U241Z84C00Z80 CPU DIP40 socket 1
U251DS1210Maxim Nonvolatile Controller Chip DIP8 socket1
U26174LS06Hex inverter buffers/drivers DIP14 socket 1
U28174LS74Dual D-Type Positive Edge Triggered Flip Flop DIP 14 socket 1
X1132.768KHz3mm Crystal 6pF
Sockets 31154232


Minimum Build

Excludes Sound, RTC, IDE interface, Battery Backup controller and super capacitor, RS232 TTL converter, ECB bus interface, 2nd Flash ROM

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_boards_sbc_sbc_v2_sbc_v2-005_gallery_sbc_v2-005c-minbuild.jpg

ReferenceComponent
C210uF
C3, C4, C9, C11-C17, C19-C23, C30, C320.1uF
D21N4148
JP3-JP4SOLDER BRIDGE
JP4-JP8SOLDER BRIDGE
P2BARREL JACK
P3IDC SOCKET
P44-10MHz XTAL + SOCKET
P51.8432 XTAL
U116550
U374LS08
U474LS10
U674LS139
U774LS14
U12, U13, U1874LS174
U14, U15, U1674LS32
U1774LS244
U23AS6C4008
U24Z80CPU
U2674LS06N
U2874LS74
U2939SF040
K10Pin Header, 1-2 BRIDGED
K11Pin Header, 1-2 BRIDGED
R110R
R210K
RR1, RR210K
RR34K7
SW1Push Button


SBC Build

Excludes ECB interface

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_boards_sbc_sbc_v2_sbc_v2-005_gallery_sbc_v2-005c-sbcbuild.jpg

ReferenceComponent
C6, C18, C33, C350.1uF
C24-C271uF
C2810uF
C340.22F-0.47F Super capacitor
D1BICOLOUR LED
JP1PIN HEADER
JP2PIN HEADER
JP3-JP4REMOVE SOLDER BRIDGE
JP5-JP8REMOVE SOLDER BRIDGE
JP9PIN HEADER
K9PIN HEADER (not requires version f+)
K12PIN HEADER, 2-3 BRIDGED
LS1PIN HEADER
P1IDC SOCKET
Q12N3906
R9100R
R1110K
R124K7
R133K6
R141K8
R15120R
R16470R
R17100K
U239SF040
U574LS125
U198255
U21DS1302
U22MAX232
U24DS1210
U2774LS14
SW2Push Button (Revision f+)


Full Build

www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_boards_sbc_sbc_v2_sbc_v2-005_gallery_sbc_v2-005c-fullbuild.jpg

ReferenceComponent
C1, C5, C7, C10,0.1uF
C3122uF
U8, U9, U1174LS245
U1074LS243
U20DIN EURO MALE RA 96

Boot ROM Installation

The firmware for the SBC V2 is called ROMWBW and can be obtained from Wayne Warthen's ROMWBW github repository.

Initial programming of the ROM requires the use of a programmer that supports Flash PLCC32 chips such as the MiniPro TL866II. Subsequent reprogramming can be done on the SBC V2 if you have enough secondary storage to hold the ROM image file. This is the preferred method as installing and removing the PLCC32 Flash chips is more difficult then the DIP32 style chips used previously.

Download the latest release i.e. RomWBW-v3.0.1-Package.zip and extract the ROM image file \Binary\SBC_std.rom. This is a 512Kb image and should be programmed to a 39SF040 (preferably) or AT49F040 and installed in flash location #1

Installing a 1Mb ROM image requires downloading, installing, customizing and assembling the ROMWBW source. Documentation on this process is detailed in \Source\ReadMe.txt file.

To assemble a 1024Kb ROMWBW rom, use the following as an example command line in the Source directory: build SBC std 1024 . The finished ROM image will be saved in the \Binary subdirectory. Before programming, split the file into 512Kb parts using a tool such as HxD.

MegaFlash Boot ROM configuration

The default configuration of ROMWBW is for the SBC V2-003 and includes the following driver options:

  • Serial port.
  • Real Time Clock
  • Colour VDU board.
  • VGA board.
  • Parallel Port IDE.
  • Propeller IO.

If the JP2 jumper “1BIT-IN” is bridged the default console will switch from Serial port to the first video card.

Some suggested configuration changes to take advantage of SBC V2-004+ features:

; SBCV2004 DEFINES A FLAG TO SWITCH TO HALF SPEED WHEN ACCESSING SOME SLOW DEVICE.

#DEFINE SBCV2004

; BEEP ON BOOT AND INCLUDE SOUND DRIVER.

SPKENABLE    .SET    TRUE            ; TRUE FOR RTC LATCH IOBIT SOUND

; RECOGNIZE THE RECMODE SWITCH ON BOOT TO LOAD MINIMAL DRIVER SET.

BT_REC_TYPE  .SET    BT_REC_SBCRI    ; SAFE MODE INPUT METHOD

; CHARGE SUPERCAPACITOR AND REPORT WHEN LOW

DSRTCCHG     .SET    TRUE            ; DSRTC: FORCE BATTERY CHARGE ON
BATCOND      .SET    TRUE            ; REPORT LOW BATTERY ON BOOT

Flash Programming

Will Sowerbutts has updated his FLASH4 program to support programming one or more flash chips. The updated Flash4 can be found in Will Sowerbutts github repository https://github.com/willsowerbutts/flash4 and is also included in the current development release of ROMWBW. As the RAM disk on the SBC V2 is smaller then 512Kb, the ROM image to be programmed must reside on an alternate storage device such an IDE flash card.

An example command line to update ROMWBW would be b:flash write std512.rom /1 or b:flash write cust1024.rom /2 for a 512Kb or 1024Kb ROM respectively.

Acknowledgement

The SBC V2-005 is based on the work of Andrew Lynch N8VEM and others in the Retrobrew Computers community. To see Andrew's foundation work, see here.

Thank you Andrew!

Contact

I can be contacted at difficultylevelhigh @ gmail.com or on the retrobrew computers forum as user b1ackmai1er

boards/sbc/sbc_v2/sbc_v2-005.txt · Last modified: 2021/02/26 23:40 by b1ackmai1er
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