This part was taken from a Motronic M1.7 engine control unit (ECU), which was used on the M42 engine of the BMW E30 318iS.

Functionally, this chip serves a variety of purposes, with the best high-level description stating that it is a programmable peripheral interface (PPI). It bears some similarity to standard devices such as the 8155 and 8255, but it is clearly a custom part based on the number of IO's. Some of the functions it provides are:

- Latching of the low-byte address (from the data lines) for external ROM and RAM accesses

- Some internal digital logic which takes the A13-15 inputs and outputs enable/disable signals on other IO pins for other ICs

- Provides additional latching IO pins

- Provides additional IO pins

- Provides additional input-only pins

- Interfaces with the external L-Line diagnostic interface which is used by various code scanner tools to initiate communication on the faster K-Line interface

There were other versions of this part used across the family of Motronic 1.x ECUs. Package markings indicate that Harris Semiconductor also made a number of these chips. Internal differences are unknown, but the functional implementation was always the same. Communication with Intersil (formerly Harris) about these parts indicates that there is no surviving internal documentation on these parts. Bosch and Philips did not respond to any inquiries about their versions of the parts.

Label (top):

[Philips Logo] [Bosch Logo]
30074 (Bosch internal PN)
9010
030972
CC151 V1
Dt

Decap Steps:
Selective crushing with pliers and bench vise

Capture Details:
Imaging device: Keyence VHX-2000
Magnification: 300X

Markings:
V733V1
[Bosch Logo]
Bosch
©1986
©1987
CC151

The die had a clear conformal coating covering it, which was left in place for initial imaging.

Subsequent efforts to remove the coating destroyed the die, so no additional images were taken of this sample.