FunDimensions Incredible Brain Buggy

Chip labeled 
TMS1000NLL
MP0915
MS^ 7923

die labeled
MP0915

9 buttons
1 switch: Pro/Run
2 motors

TMS1000 pinout
1  R8   - N/C
2  R9   - N/C
3  R10  - N/C
4  VDD  - 9v - via switch
5  K1   - button matrix
6  K2   - button matrix
7  K4   - button matrix and R5 and R6
8  K8   - button matrix
9  INIT - cap and diode
10 O7   - N/C
11 O6   - N/C
12 O5   - N/C
13 O4   - N/C
14 O3   - VSS
15 O2   - Left
16 O1   - Forward
17 O0   - Right
18 OSC1 - connected to OSC2 and 47pF disc cap (to VSS) and 47K resistor (to VDD)
19 OSC2 - OSC1
20 VSS
21 R0   - button matrix
22 R1   - button matrix
23 R2   - button matrix
24 R3   - button matrix
25 R4   - button matrix
26 R5   - R6 and K4
27 R6   - R5 and K4
28 R7   - N/C


button/switch matrix
        K1          K2           K4          K8
      ------------------------------------------
R0      --         Pro           --          --    
R1     Left      Straight      Right         Go
R2      --          --           --         Stop
R3      --          1            --          2
R4      --          3            --          4