RoadTest: element14 and Freescale XL Star Development Board
Author: KioseusZnook
Creation date:
Evaluation Type: Evaluation Boards
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?:
What were the biggest problems encountered?: None.
Detailed Review:
[Soon after starting to review the XL-Star I succumbed to long-term illness (not from the product I hasten to add) and was unable to continue. The following was what I'd written up until that point. 12/02/14]
XL_Star S08 8-bit MCU-based Multifunction System
1: The Arrival/element14/Road Test experience
The XL_Star development package finally arrived approximately 5 weeks after the Road Test closing date. The reason for the delay being that I had never received any notification that I'd been successful in getting one for review, and it was only by chance three/four weeks later that I saw my username on the XL_Star Road Test page with 'Review Pending' after it. After contacting element14 about this a new package was quickly despatched, unfortunately sent from the US, and I ended up paying a customs charge to receive it. Annoyingly I later discovered that the XL-Star board actually originates from the UK so in the end I'd paid a fee to receive it back! [Despite being offered a refund of these duties to this date I never did.]
2: The Package
The XL_Star board arrives in a small white thin card box measuring 140x133x42mm (WxHxD), adorned with a printed label covering the top and front faces. This, as another Road Tester pointed out, shows an image of the XL_Star board that's slightly blurry - as first impressions count this really needs to be changed to something more suitable.
Inside the box are the following parts: the XL_Star board itself sandwiched between two pink dimpled foam panels, a USB A to USB mini B lead and a single CD. No paperwork of any description is included, which is par for the course nowadays, however in this case I feel a single sheet giving a quick overview of how to use the ready-programmed demo would be a worthwhile inclusion.
3: The XL_Star Board
The XL_Star board measures 84x64 (LxW) with an extra 3mm on its length for the protrusion of the slide switch control. The printed circuit board (PCB) is well finished having smooth edges, a good quality green solder resist mask, and a good selection of clear white legends denoting the parts and connections. There are a few removable parts on the board as supplied: the 'Target BDM' 3x2 header is covered by a single plastic protection cap, and there are two 2x1 jumpers, one on the header marked JP1, the other on JP4.
On the top of the board is a USB port labeled 'User USB' and, being on the top, you could in your eagerness to get the board powered up connect your supply/computer to here. As has since been discovered to do so could render your XL_Star board inoperative, or at least cause some damage to the main MCU's internal voltage regulator. In the spirit of testing things out I tried it (oh okay, I admit I did it before finding out about this issue!) - thankfully no damage was caused but I was lucky - my board is a Revision B model and as such didn't contain the full complement of star configuration LEDs. If it had then the extra current needed to light them all would have been enough. To prevent this issue occurring there's a relatively easy fix - carefully drill out one of the via holes located near to the USB port so disconnecting the MCU's 3V3 regulator output from the board's main 3V3 power line. As it stands at the moment until the new Revision D(?) boards become available I'd suggest Newark/Farnell notify purchasers of the XL_Star development system of this problem via a note on their order delivery sheets so that they can avoid this costly mistake.
The star configuration of the LEDs on the top side is what gives the development board its name. With my board being Revision B it only contained the central ring which was just enough to make the board useable. I decided soon after its arrival to purchase and install the rest (40 off) and, although it's doable, it's an experience best avoided. Thankfully I believe the current Revision C boards have them all installed from the get go. This is a good move by element14 as the time and patience required by the end-user in installing them is removed, and the board will look better anyway if they're all done at the same time. Having seen the board operate with just the inner ring available, and also in the fully populated state, the XL-Star board definitely benefits from having them all installed. The pre-programmed demonstrations are more vivid, and it look pretty darn cool seeing all those babies light up!
On the bottom of the board there is another MCU along with another USB port labeled 'PC USB'. This is the one to utilise in powering up the board. There is also provision for a battery clip to be added so allowing the board to operate without it being tethered to a power supply. Having decided to install the LEDs I decided I might as well purchase and install the battery clip too, although at this moment in time I have no intention of using it. I believe all boards now sold include the clip, but are not actually soldered to the board. This is quite easy to do with a decent iron/soldering tip combination.
Other points to note regarding the board itself - there is an unpopulated 3x2 header on the top side labeled 'JM60 BDM' As this would only be used to program the MCU located under the board (it's currently pre-programmed with the debug firmware), I can see the reason why it hasn't been installed. After consideration, I decided whilst I was in soldering mode, to install the header because I'm a 'you never know when you might need it' sort of guy.
I also took the opportunity to install the two 32x1 pin headers along each edge of the board as, with it being for development purposes, makes for an easier way to connect flying jumper leads to a breadboard.
4. The Software
The accompanying CD contains a variety of software, as well as an assortment of documents. Installing the Windows software was a breeze and communications via the USB port were quickly accomplished. Programming was easy, and the step by step run function worked as intended. All in all the XL-Star board is a neat little development board.
