A tale of two boards

May 24, 2011

Lately I’ve been keeping my eye on two recent developments from Xmos and Parallax.

The Xmos staff are developing a Stamp (40-pin DIP package PCB) like board for their XS1-L1-TQFP48.

Mean while Parallax to support their Semiconductor spin off have brought a new Quick Start board of their popular Propeller P8X32A multicore microcontroller.

Cheaper Sparkfun XMOS XS1-L1-64 Development Board

September 29, 2010

Sparkfun has announced a cheaper version of the XMOS XS1-L1-64 Development Board.

This cheaper revision does away with the FTDI USB based UART section of the board, which never really worked anyway. The IC footprints are still there so you can solder them yourself if you want.

$41.95 (£26.49)

You still need a XMOS XTAG2 Debug Adapter to program it and these cost $50.95 (£32.17).

Maker Faire @ Newcastle 2010

March 19, 2010

We had a great time at this years Maker Faire in Newcastle over the weekend of 13th and 14th March 2010.

My kids, who are almost teenagers, were dragging their heels as we left our parked car, totally sure they weren’t going to have a good time as we walked towards the Centre of Life.

Walking up the foot bridge to mezzanine level of the maker faire, you could hear the crackling of the musical tesla coil, then as you reached the mezzanine level you were hit by a wall of sound from the various gadgets and things beeping and booping, the musically exhibits being played and of course the Tesla coil. Their faces slowly changed as they realised there was fun stuff here and after a couple of nervous minutes getting their bearings off they went and for the rest of the day it was like trying to herd cats. 😀

I don’t think I saw a single kid, young or old who wasn’t enjoying themselves.

I was finally able to meet up, put a face to a name, with Baggers, Coley, TonyF and Leon from the Parallax and Xmos forums. Leon was being provocative in wearing his Xmos t-shirt whilst on the Parallax Propeller stand with Baggers and Coley. Coley got his own back by having on display a Xmos XC-1 board with a “powered by propeller” label stuck over the Xmos chip. Good nature ribbing 🙂

I had a great chat with John Honniball about his UK101’s he was displaying (I wish I had one for my collection of retro computers 😉 ) and his Arduino music synthesiser.

We met up with Jim and Kat from Sonodrome who were showing off their PSOC (pocket oscillator) and Tubby amps. On Sunday Jim help Sid build his own PSOC. He took it to school for a show and tell and his teacher and class loved it. His teacher was especially impressed that Haydn had soldered it all himself (with a little help).

Abs, not to be left out, spent the afternoon building a mignonette handheld LED game at the Maker table with a little help from me.

Leon has posted some pictures from the faire:



Jim and Kat from sonodrome have also posted some pictures:


and Jonathan Street has a nice write up here:


XArduino – A 400-MIPS co-processor for Arduino

February 7, 2010

Recently I’ve been working on XArduino which is a XMOS XS1 L1 co-processor for the Arduino open-source electronics prototyping platform.

The XArduino board provides Arduino applications with a 400 MIP’s multi-threaded 32-bit co-processor, as well as providing a VGA video output and PS/2 keyboard/mouse input for Arduino application.

It features a standard XTAG-2 to for programming and debugging. In addition the XTAG-2 interface will allow for XK-1 boards to access the VGA and PS/2 interfaces as well as way of connecting standard Arduino shields.

Note: This is a 3.3V-only board

The project is hosted at xcores.com/projects/xarduino

Creative Commons Attribution-ShareAlike 3.0 License

X-DTV – Preliminary schematic and PCB v0.42

January 7, 2010

X-DTV is a project I’ve been working on with Yvo of xcores.org. The idea is to make a XS1-L1 64 based retro-minimalist homebrew game console similar in concept to the Uzebox and Zuzebox.

Like the X-One before it, X-DTV will use Yvo’s VDP video engine but instead of driving a VGA output it will drive a NTSC TV output. We hope to get PAL TV as well but the 35.46895MHz oscillators have proven difficult to get a hold off (If anyone know where we can get them off the shelve without a large MOQ then drop me a comment).

The X-DTV’s specification is:

  • XS1-L1 64 internally clocked to 400MHz with 64K RAM.
  • 5-bit R-2R Video DAC for driving NTSC
  • 2x NES or SNES D-PAD connectors
  • SD Card interface
  • Stereo PWM audio
  • XTAG-2 Interface
  • 2x 5-way XLINK for expansion

The latest (not quite complete) PCB is below:

A PDF of the schematic is here.


December 13, 2009

The xcore exchange has been launched. Reading the press release its says:

“this new site is to create a community of enthusiastic XMOS users with an entrepreneurial spirit. We want to encourage you to share designs and code as well as develop your ideas.” .

Sounds cool.

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

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

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.