tetris/rgb-driver/readme.md

## Debugging

```
mspdebug rf2500 gdb

msp430-gdb -x firmware.gdb
```

Attention: the gdb in the TI toolchain package is broken, use the one from Debian



## Signals Working Cycler

These signals are related to code under tag `cycler_works_include_output_stage`.

First octets:

![](./docs/cycler_working_first_octets.png)

Last octets:

![](./docs/cycler_working_last_octets.png)

Schematics and legend for signals:

![](./docs/schematics.jpeg)


## Timing

Complete cycle: 2.48us

![](./docs/pulse_complete.png)

Short pulse: 550ns

![](./docs/pulse_short.png)

Long pulse: 1.18us

![](./docs/pulse_long.png)


## Load Time

During of loading data into five LEDs: 297us

![](./docs/five_leds.png)

During of loading data into six LEDs: 297us

![](./docs/six_leds.png)


| # of LEDs | Load Time measured | calculated |
| --------- | ------------------ | ---------- |
| 5         | 297us              |            | 
| 6         | 354us              | 356.4us    |
| 10        |                    | 594us      |
| 100       |                    | 5.9ms      |
| 200       |                    | 11.8ms     |


## Reset Circuitry

It appears that the output voltage of the power supply raises that slow, that the MCU
will not handle the reset correctly.

The following circuitry should generate a valid reset signal far enough from the raise 
of the supply voltage:

![](./docs/reset-circuit.jpeg)

The circuit generates the following signals:

![](./docs/reset-signal.png)

#### Reference voltage (green):

```math
U_ref = 3.3V \frac{22k\Omega}{22k\Omega + 10k\Omega} = 2.2V
```  
  

#### Trigger voltage (purple):

```math
U_trigg = 3.3V \frac{330k\Omega}{330k\Omega + 82k\Omega} = 2.64V
```  
  

#### RC constant:

```math
\tau = 82k\Omega \cdot 100nF = 8.2ms
```