Req for info on Motorola cpu

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I'm working on an engine management controller from an early 90's car,
(Mazda MS-6) which
uses an ECU made by Nippon Denso. Most of the technology is easily
identifiable due to its
age, unlike more modern units.

This unit is based around Motorola chips, including a 6821 pia and a 6840
timer. The cpu
is a Motorola special, type SC402617FN and obviously made for Denso as it
has their
logo on it.

Looking at the firmware shows that its based around a 68HC11 core, but which
The package is an 84 pin plcc.

I would very much like to at least identify the pinouts and extra on-board
of the chip so if anyone can assist I would be most grateful.

This is a project I am working on to try and understand how the cpu can keep
of sequential fuel injection at high speeds while attending to all the
multitudinous tasks
it has to monitor.

John Dyer

Re: Req for info on Motorola cpu
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The injection scheduling is handled using a TPU (Time processing
unit).  A TPU is a processor component which features on many Motorola
automotive controllers.  It is normally associated with 16 channels
and can provide a range of time related functions, such as PWM, UART
or injection control without processor intervention.

More information is available here:

Most engine control applications use custom TPU microcode for the
scheduling.  For a high volume application this microcode can be
incorporated onto a custom version of the device.


Re: Req for info on Motorola cpu

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None of the 8 bit parts had a TPU, neither did the HC12 or HC16 family.
You had to get into the embedded 683xx parts and 5xx PPC parts to get
the TPU.

Dave Rooney

Re: Req for info on Motorola cpu

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None of the 8-bit parts had a TPU, but the high-end 16-bit parts had a TPU
(not that I know if the parts in question were "high-end 16-bit parts" -
it's just that if they were, then they had a TPU).  That's part of the
reason why the TPU has a sometimes limiting 16-bit feel to it, even though
it is used mainly in 32-bit parts.  Maybe the new eTPU has thrown out the
16-bit baggage?

Re: Req for info on Motorola cpu

Go to the Freescale Semi. (was Motorola) site,  Then
products --> microcontrollers ---> 8bit.

It looks like the HC11K4 comes in an 84 pin plcc.  In the old selection
guide they had the package, but not in the latest one.  Just takes a
little poking around at the parts with large I/O counts to find the 84
pin versions.

Dave Rooney

John Dyer wrote:
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Re: Req for info on Motorola cpu

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"SC" on Motorola parts means semi-custom. Could be an HC11 with some extra

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