235 Programmable Thing
235 : Programmable Thing
- Author: James Meech
- Description: One inverter and a programmable resistor with one terminal connected to ground
- GitHub repository
- Clock: 0 Hz
How it works
The project is a programmable resistor controlled by setting ui[0] to ui[7] and ui[0] to ui[7] high to connect a set of 58.218 k ohm resistors between pin ua[0] and ground in parallel using programmable analog switches. There is also an inverter with analog pin ua[5] as an input and analog pin ua[4] as an output. Try using the inverter as an amplifier as explained here: https://www.youtube.com/watch?v=03Ds1TnoMbA&ab_channel=MSMTUE and see if you get the same results when trying to use the inverters in my digital tile as an amplifier: https://github.com/JamesTimothyMeech/TT06/blob/main/info.yaml
How to test
Apply inputs to the inverters with a square wave or other signal generator and measure the output. To test the programmable resistor connect the supply voltage in series with an ammeter to pin ua[0]. Set ui[0] to ui[7] and ui[0] to ui[7] high to connect a set of 58.218 k ohm resistors to ground internally inside the chip. You should be able to measure differences in current as you connect each resistor to ground by setting the corresponding digital input pin high.
External hardware
TT06 printed circuit board, signal generator, an oscilliscope or similar to measure the input and output.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch | Not used, grounded internally | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch |
| 1 | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch | Not used, grounded internally | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch |
| 2 | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch | Not used, grounded internally | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch |
| 3 | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch | Not used, grounded internally | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch |
| 4 | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch | Not used, grounded internally | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch |
| 5 | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch | Not used, grounded internally | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch |
| 6 | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch | Not used, grounded internally | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch |
| 7 | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch | Not used, grounded internally | Control pin to connect one of the 16 resistors between ua[0] and ground using an analog switch |
Analog pins
ua | PCB Pin | Internal index | Description |
|---|---|---|---|
| 0 | A5 | 5 | Internal programmable resistor connected to this pin |
| 1 | A0 | 0 | Analog pin not used |
| 2 | A4 | 4 | Analog pin not used |
| 3 | A1 | 1 | Analog pin not used |
| 4 | A3 | 3 | Analog inverter output |
| 5 | A2 | 2 | Analog inverter input |