hello people!

i hope you dont mind, that i am writing in english.
i am looking for information on the hitachi-IC:  "HD46510".
it is a 42-pin DIP and was produced around 1982;it is used together
with a hd6802W-microcontroller in the ECU of my nissan pulsar.
i think its function is a multiplexed A/D-converter, input/output,
timer..?

i hope anyone can help me or tell me where to find help...

thank you in advance 
&
greetings from austria
h.mullen