8-digit calculator, 9 function (+, -, x, /, %, $, SQRT, X^2, 1/X), seven memory functions

Keyboard Matrix: 

      KN    KO    KS   Note: KS = KN && KO 
 D0         CM
 D1   1     %
 D2   2     sum   =
 D3   3     M-=   M-
 D4   4     SQRT  X^2
 D5   5     1/X   .
 D6   6     $     /
 D7   7     M+=   M+
 D8   8     XM    x
 D9   9     MS    -
 D10  0     MR    +
 D11        C/CE

Note: D0, D10, D11 are for keyboard matrix only

Taken from data for MK50311 chip which has the same pinout, I have assumed same functions, might be wrong … The TRQ F-85 calculator, that uses this chip, has a switch with two positions 'N' and '∑', I'm not sure how this is connected. I think it may switch a line between the 'KS' column and the 'KO' column, so if that line is connected to the ”=” key it would switch its function from ”=” to “sum” going by the table above. (The wiring of the TRQ F-85 board confirms the keyboard digit→row associations) ¹⁾

• Corvus 615
• Corvus 615
• Corvus 804
• F-84, Electrónica Querol (TRQ) F84. ²⁾
• F-85, Electrónica Querol (TRQ) F85. ³⁾