X-One – Preliminary schematic v0.10

November 24, 2009

I’ve talked a few times about the X-One Xmos based console so I thought better put up a schematic to show how it all goes together. A Xmos XC-2 is found at the heart of the console with the rest of the circuit providing a R-2R video DAC, PWM audio and SD Card interface. Ethernet is provided by the XC-2 card its self. The software kernel is Yvo’s VDP video engine.

The pdf is here: XC-2 VGA 0v10

Zuzebox – at last the PCB is started

November 15, 2009

I finally found some time to start the PCB for Zuzebox (a Uzebox compatible retro-minimalist homebrew game console). I’m hoping to squeeze it all into a 100mm x 100mm board so I can use Seeedstudio’s Fusion / Propaganda PCB service. The picture below only shows about half the components laid out, so I think the final PCB is going to be busy.

Zuzebox - starting PCB layout

Xmos Development Board comparison

November 13, 2009

With all the recent Xmos development boards coming out I thought it would be a good idea to compile a comparison list. The full list is here (pdf) but a quick comparison of those boards costing less than $100 is shown below:

Feature Xmos





XS1-L1 64

Cost $99.00 $99.00** $49.95
Processor XS1-G4 XS1-L1 XS1-L1
# Pins 512 128 64
# Cores 4 1 1
Max MIPS 1600 MIPS 400 MIPS 400 MIPS
Memory – RAM 4x 64Kx8 64Kx8 64Kx8
SPI Flash 0 512Kx8 128Kx8
User I/O 60 I/O 24 I/O 32 I/O
User Interfaces USB none USB
User LED’s 12 4 2
User Switches 4 2 none
Programming I/F via USB JTAG JTAG
XSYS I/F none 2 1
Other I/F Speaker none none
Board Size 85 x 54mm 50 x 50mm 84 x 64mm


** Includes Xmos XTAG2 USB-JTAG programming adapter (costs $50)


Port details for the Sparkfun XS1-L1 64 Development Board

November 11, 2009

Port details for the Sparkfun XS1-L164 Development Board (pdf is here)

Ports for XS1-L1 64
Pin Name Pin ID 1-bit 4-bit 8-bit 16-bit Description
X0D0 16 P1A0 MISO
X0D1 15 P1B0 SS
X0D2 14 P4A0 P8A0 P16A0 JP15 #25
X0D3 12 P4A1 P8A1 P16A1 JP15 #24
X0D4 11 P4B0 P8A2 P16A2 JP15 #23
X0D5 10 P4B1 P8A3 P16A3 JP15 #22
X0D6 7 P4B2 P8A4 P16A4 JP15 #21
X0D7 5 P4B3 P8A5 P16A5 JP15 #20
X0D8 3 P4A2 P8A6 P16A6 JP15 #19
X0D9 2 P4A3 P8A7 P16A7 JP15 #18
X0D10 1 P1C0 SCK
X0D11 64 P1D0 MOSI
X0D12 63 P1E0 JP15 #17
X0D13 62 P1F0 JP15 #16
X0D14 59 P4C0 P8B0 P16A8 JP15 #15
X0D15 58 P4C1 P8B1 P16A9 JP15 #14
X0D16 57 P4D0 P8B2 P16A1 JP15 #13 / TXU1
X0D17 56 P4D1 P8B3 P16A1 JP15 #12 / TXU0
X0D18 55 P4D2 P8B4 P16A1 JP15 #11 / TXD0
X0D19 54 P4D3 P8B5 P16A1 JP15 #10 / TXD1
X0D20 51 P4C2 P8B6 P16A1 JP15 #9
X0D21 50 P4C3 P8B7 P16A1 JP15 #8
X0D22 49 P1G0 JP15 #7
X0D23 48 P1H0 JP15 #6 / TX-O
X0D24 47 P1I0 JP15 #5 / RX-I
X0D25 46 P1J0 JP15 #4
X0D26 45 P4E0 JP15 #3
X0D27 44 P4E1 JP15 #2
X0D32 36 P4E2 JP9 #5
X0D33 35 P4E3 JP9 #6
X0D34 34 P1K0 JP9 #7
X0D35 33 P1L0 JP9 #8
X0D36 42 P1M0 JP9 #1
X0D37 41 P1N0 JP9 #2
X0D38 39 P1O0 JP9 #3
X0D39 38 P1P0 JP9 #4

Zuzebox v0.30 – an update

November 8, 2009

It’s taken me longer than I hoped to make this small update to Zuzebox (an Uzebox compatible retro-minimalist gaming console). What I’ve done with this update is to actually simplify the design by removing the surface mount components for the USB circuit. I still intend to have the USB interface but I’ve decided to use a plug in USB module instead of a surface mount chip.

The idea is to keep the electronics as simple as possible and to add functionality such as a USB or a Ethernet interface through plug in modules. I’ve updated the schematic to use Sparkfun’s USB module shown below:

Sparkfuns USB Module

I may added another USB module footprint in the future, possibly a FTDI module.

The updated Zuzebox v0.30 schematic (pdf) is here.

Sparkfun XS1-L164 Development Board

November 7, 2009

Sparkfun have a new Xmos based development board. It features the powerful Xmos XS1-L1, multi-threaded processor. The processor is the XS1-L1-64 processor and is housed in a 64LQFP package and has the following features:

  • Event driven processing at 400MIPS
  • 64 kBytes of SRAM
  • 8 threads
  • 36 user I/O pins
  • 8 kBytes of OTP
  • power consumption typically 450µW/MHz

sparkfun XS1-L1-64 2

As well as the Xmos processor the SparkFun development board also features a USB interface based on FTDI FT232, external Flash EEPROM and a JTAG header. I/O is provided by 32 I/O pins brought out to pin headers next to a small prototyping area. Checking out its schematic, it looks like it can be powered form both a wall adapter and its USB port. The USB interface is to support a UART over USB and can’t be used to directly program the processor. Instead a 20-pin JTAG interface is provided. This looks to be compatible with Xmos’s own XK-1 JTAG interface and therefore Xmos new XTAG2. I’m hoping my XC-2 JTAG adapter will work with it as well.

Its competitively price at $50 or ~£30 but you still need to provide a JTAG adapter but these are available for $50. The only criticism I would make is I would liked to see the on board USB used to provide a programming (JTAG) interface as Xmos did with their XC-5 board but that said I’m hoping to get one soon and use it in my X-One console with Yvo’s VDP VGA video driver.

Manic Miner on X-One Console

November 3, 2009

As promised in my post of 15th October, here’s some screen shots of Manic Miner on my Xmos XC-2 based X-One console. So far I’ve only coded level 1 and I need to add code for the SNES controllers and game play and off course the rest of the 20 levels to finish it off.

Manic Miner Lvl 1

The graphics were hand coded by extracting the pixel data and colour attributes for the first level from a Manic Miner ZX spectrum binary. A very mandraulic process involving switching between two editors and a couple of editor macros but it got the job done. I used Andrew Broads and Icemans (Chris Wild) excellent web sites for the screen layout information. The video engine is Yvo’s VDP for the XC-2 which provides up to 2 backgrounds and up to 32 sprites (8×8, 16×16, 32×32, 64×64 etc)

Manic Miner on X-One
Watch this space more to come.