SPD Tool

Found an interesting tool for reading SPD data from your DIMM's on your PC. Was looking for a tool that could do this for a system we're working on, however it doesn't support DDR3 or ICH10 access at the moment, so until then I'll have to find another way to access this information.

SPD TOOL 0.63

If anyone has a tool or knows of a tool for reading or writing SPD data for DDR3 DIMM modules, supporting an ICH10? I'd be very very appreciative!

Created a small RS232 Transceiver yesterday

On a current project we're working on, we had a serial port output which came from the BMC, but there was no RS232 to level shift the TTL levels. In this design, the RS232 transceiver is on the adjoining system which connects to this serial port.

So for testing purposes, to test this serial port we needed to either invest in a special cable with it all built in or make one ourselves from locally available parts. Unfortunately we weren't able to wait for the arrival from Farnell of the USB to TTL cable from FTDI (TTL-RS232-3V3). So I drove down to Maplin and picked me up a small Maxim RS232 transceiver (MAX3232CPE), 5 0.1uF ceramic disc caps and a male and female serial port header. Back in the labs, I snapped off a bit of unused bread-board, soldered in the part, cut the tracks beneath the device to isolate the pins on either side. Attached the 0.1uF caps, wires and I got 3V3 from the front of a capacitor on the actual system itself. Attached the thing up and lo and behold... it didn't work :(

I had the TX and Rx the wrong way around. I was using a crossover cable which swaps the Tx and Rx when going from my device to the Host PC. Once swapped, the yoke works proper. I haven't tested to see how clean the signals are yet, but it should work like a beauty.

The easy part was knowing where to hook up the caps and what to solder to where, it's all freely available on Maxim-IC's website MAX3222-MAX3241 DATASHEET (PDF).
See page 12 for the exact circuit I used. If using a different input voltage to 3V3, then check out table 2.

Reading the IPMI Spec

I'm currently trying to read the IPMI specification so that I can re-program a Serial EEPROM over I2C. I think I'm using an IPMB command to do so. I connect over the UART and login to the BMC using hyperterminal. Now our BMC code hasn't been finalised yet so it may or may not work. I'm hoping that I can figure out the commands as it would really save time and work if I could program the devices this way instead of removing the device, programming it using an external programmer and then soldering it back onto the board.

Unfortunately we don't have an in-circuit programmer as this would be very useful indeed. I figure that this way I learn how to access something and gain knowledge on a subject I have never touched before. Another notch in the belt as you may say.

What a great week!

In work terms, this has been a great week. I'm on top of my game on nearly everything I've done. I found a solution to one of our Infiniband issues we've been having trouble with all week. I've successfully reworked a number of boards back into good working health and I'm unofficially referred to as the Mellanox expert. I'm on a roll. Now if I could only fix this one last board before the weekend, it truly will have been a great week.

I haven't seemed to have any luck with writing to the Serial EEPROM over the BMC interface yet. Will have to figure that all out from the IPMI Specifications as to how to write the commands correctly into the device. I'd be happy just being able to read the device at the moment.

Unfortunately topping this week, next week is going to be a real challenge. I'll have to work extra hard.

Also this week, I've purchased two new books from Amazon.co.uk

VHDL: Programming by Example (Hardcover)
Verilog HDL: A Guide in Digital Design and Synthesis (Hardcover)

So I hope to get my butt in gear and get learning Verilog and VHDL so I can finally read and understand the code they use here and I can debug the boards completely, looking at timing relationships and the signals as they bring up the board.

Good luck to Vlad

All the best to Vladimir Zaytsev, one of our BIOS engineers who is top of his game. He's moving to California to join a startup company and live with his girlfriend in Los Angeles. He is a great engineer and he will be missed here in the company.

Intel's Embedded Design Center

Awesome, I just got private access to Intel's Embedded Design Center. It truly is incredible. Am currently watching a TechTalk video for an introduction to signal integrity. Basically it explains the important factors on using an Intel reference board design and what considerations to note down when deviating from the current tested design.

I'd highly recommend gaining access to this site as it seems to be quite an incredible tool to use.

Intel sites for embedded computing

Intel came into us yesterday for an overview and roadmap presentation. We work a lot with Intel and I found this extremely useful. It is interesting to see what upcoming products they have and the support they have in place for helping with current products.

Two very helpful websites are ark.intel.com and edc.intel.com. The Ark site is helpful for translating codes on their devices into specific data relating to the device itself. IF for example you are working on a project with an as of yet unreleased Intel device with a specific codename and then it is released into production, this codename will no longer be used. But using Ark you can find out the exact details regarding this product.

edc.intel.com is the Embedded Design Center for Intel and it contains a number of blogs, forums and access to a wide range of technical datasheets and information regarding the use of their products and what they support.