Replacing a surface mount processor.

[Dave Plowman (News)]

Yes - saw this technique on one of the videos a link was posted to. Looks promising.

[Theo Markettos]

All MC9S12C-Family / MC9S12GC-Family members feature standard on-chip peripherals including a 16-bit central processing unit (CPU12), up to 128K bytes of Flash EEPROM, up to 4K bytes of RAM, ...

(gbp7.99 at Mouser, if you can make the shipping cost work)

A microcontroller these days without embedded program memory is a pretty rare beast.

Is there a programming header on your board? And do they publish the firmware files for each particular board? Especially if there are multiple boards available, compiling the source might turn out to be rather awkward in making sure you've got it right.

Theo

[alan]

The other advice is DON'T use lead free solder. Use a 60/40 tin/lead solder which will have a lower melting point (by 40 to 60C)

If you bridge some pins just apply more flux and slide the iron down the pins again.

[Dave Plowman (News)]

My experience of importing such things (from the likes of Digikey - who even have a UK website) - is the delivery costs are astronomic. But thanks very much for the link.

What I think I meant is MS uses it as it come from the factory - and the user adds the MS code. (That's for an MS DIY kit - buy a ready made one and it will come with the appropriate code loaded)

This is from the description in the manual:-

************************************

This section explains the bootloader options which are available on the MC9S12C32:

1) The 9S12C32, when it comes from the factory, has a section of flash programmed with a LRE code - this stands for "Load RAM and Execute". At reset on a unprogrammed device, the SCI (and CAN module) will try to communicate with an external host which will allow the upload of user code into RAM, followed by execution of this code. It is very similar to the bootloader used in the HC11. The user has to provide the RAM code to be uploaded (i.e. a routine which grabs S-records and burns flash).

2) There is a much more elaborate bootloader available for the C32 (compared to the one implemented in the HC08).

This bootloader not only allows the upload of new code via the serial port, it also allows debug access to accor via. the serial link. In other words, code development and debug can occur over the serial port without the use of a BDM cable.

What all this means is that a factory fresh MC9S12C32 can be programmed using the serial interface (without BDM), first by using the LRE function and burning flash with the serial bootloader in (2), then using the serial bootloader to upload the final application. In addition, the bootloader can be used as a debugger for the EFI code, and even invoke the on-chip breakpoint module and trace.

***************************

Yes

Yes

There are two individually developed 'codes' for MS, both of which use the same basic hardware, but with some mods depending on what the user needs. However, the card containing this processor remains the same.

[Dave Plowman (News)]

Right - I have plenty of that in four diameters. ;-)

Yup. It looks oh so easy in those videos.

[Dave Liquorice]

Agreed, they do make it look too easy but it really is. The key is clean pads and pins, don't skimp the flux and don't have too much solder on the iron. Think about how little is actually required for each joint, it's naff all.

Seeing what you are doing is the hard bit, especially with my eyes. Magnifying lamp essential. B-) Holding the chip in the right place for the first side may be another tricky bit.

[alan]

Holding the chip in the right place for

Just tack down (roughly solder) a corner - it doesn't matter if you bridge pins at this stage.

[Bob Eager]

Kapton tape.

[Theo Markettos]

As an aside, has anyone managed to solder double-sided boards by hotplate or hot air? For example, DRAM DIMMs tend to have chips in the same places on each side of the board. If you try and solder the second one, the first one on the other side will fall off. Since these are BGAs you can't glue them down. So how is it done?

Theo

[Dave Plowman (News)]

Clamp them in place with a G-clamp?

[John Rumm]

Never tried one - but I would expect there is a narrow window of temperature where you can get away with it.

Gravity in the first instance - and the surface tension of the solder pulls it into final position and alignment as the solder balls reflow.

[Man at B&Q]

Same as normal. Surface tension holds the package in place during the second reflow. There are a few things to condider such as the component weights (try to arrange for heaviest components to be on top during second reflow) and vibration due to the hot air flow.

MBQ

[Phil Addison]

Bit late, I don't stop by so often these days, but this is a guide I bookmarked some time ago - its still there and is *comprehensive*. A bit OTT for a one off but you get an idea of what kit the pros think they need. :O)

Head for chapter 8.3.1 "Component Removal, Surface Mount J Lead Components, Conduction Method"

Phil

[Jules Richardson]

Me too - but Dave, is it worth trying to bake the board for a few minutes just to see if it's a flaky solder joint which might sort itself out? It depends what else is on the board which might possibly be damaged by cooking it of course, plus there's no guarantee that it would be a permanent fix, but maybe it's worth a shot?

cheers

Jules

[Dave Plowman (News)]

I've identified the output pin which is faulty and resoldered it - one of the first things I did. And checked the PCB track associated with it. I'm as confident as I can be the chip is toast.

[Dave Plowman (News)]

I've been told you do have to load a bootloader code (if that's the correct name, as I'm not into programming at all). Requires a BDM board/cable, but the actual code is avaialble. Still be cheaper than a new board and something else to play with. Although the mention of Code Warrior fills me with dread.

[Man at B&Q]

Some chips come from the factory with a bootloader (ICBA to look up the particular one). If so, use it to upload the application via serial or whatever.

If you need to get a programming cable or dongle to program the bootloader first, then you may as well program the application code at the same time.

MBQ

[Dave Plowman (News)]

That's what it sort of says on the description I posted earlier. But found a thread on the MS forum which talks about needing the BDM cable and software to upload what I think is some form of boot loader code. (I'm rather out of my depth with this sort of stuff - I'm more a soldering iron type. ;-))

It's actually a prog in DOS which uploads the latest code to the MS via the normal serial cable. I wouldn't have a clue how to alter any of that. Bust if I read things correctly, you only have to upload the boot loader code the once after fitting a new chip - after that it just becomes a normal Megasquirt, as far as changing the 'working' code goes. Which I've done on lots of them. Once you've installed this 'working' code, any changes to the tune etc are made using a prog called Tuner Studio, which is a bit more understandable to me.

[Man at B&Q]

Well, BDM, at a first guess, to me, means background debug module and could imply some kind of jtag interface in order to program a completely blank device. It would not expect a straight serial cable and a DOS utility, unles it relies on twiddling the flow contorl pins to do things in which case it wil not work on recent flavours of Windows.

Another guess, are you using the basic bootloader in the chip to upload a more capable bootloader that can then upload and flash the application? If so then a basic serial connection is could be OK.

MBQ

[jkn]

Hi Dave if it turns out that you *do* need a BDM cable, give me a shout - I use d to have a stack of them (google for 'Macgraigor wiggler') and you are wel come to have one ... un less I cleared them all out a month or two ago.

BDM is a bit like an old-school version of JTAG, usually used on Motorola p rocessors. The 'wigglers' connect to the parallel port on your PC (as menti oned, you probably don't want to be runnig windows > W95 or so ;-( ) and th ere is some SW to download the firmware you already have.

HTH J^n