Small Thingy
The circuit deals with the following things:
- Controls the Inc/Dec circuit at the bottom
- Generates the
Thingy_to_botsignal ("write to the IE register")
| Signal | Type | From/To | Description |
|---|---|---|---|
| w8 | input | Decoder2 | PCL/PCH to abus/dbus |
| w31 | input | Decoder2 | |
| w35 | input | Decoder2 | |
| w6 | input | Decoder2 | WR |
| ALU_to_Thingy | input | ALU | ALU CarryOut |
| TempZ | input | Bottom | Flag Z from temp Z register (zbus[7]) |
| TTB1 | output | Bottom | 1: Perform pairwise increment/decrement (simultaneously for two 8-bit IncDec halves) |
| TTB2 | output | Bottom | 1: Perform decrement |
| TTB3 | output | Bottom | 1: Perform increment |
| bot_to_Thingy | input | Bottom | IE access detected (Address = 0xffff) |
| Thingy_to_bot | output | Bottom | Load a value into the IE register from the DL bus. |
