12 feb dupa done slideuri digital signals extra

Author: Daniel Rosner

slides/lectures/acs_cc/02/slides.md

@@ -101,7 +101,11 @@ src: ../../resources/embassy-rs/slides.md
 ;---
 
 ---
-src: ../../resources/signals/slides.md
+src: ../../resources/signals/basic.md
+---
+
+---
+src: ../../resources/signals/extra.md
 ---
 
 ---

slides/lectures/resources/signals/ICs_same_voltage.svg

@@ -53,7 +53,7 @@ Signal that what we actually generate
 
 </div>
 
-> Why we sill use it? Because after passing through an IC or a gate inside an IC - the signal si "rebuilt" and if the "digital discipline" described in the following is respected - we can preserve the information after numerous "passes"
+> Why we sill use it? Because after passing through an IC or a gate inside an IC - the signal si "rebuilt" and if the "digital discipline" described in the following is respected - we can preserve the information after numerous "passes". Thus, each element can behave with a large margin for error, yet the final result is correct.
 
 ---
 ---
@@ -65,6 +65,4 @@ Signal that what we actually generate
 
 </div>
 
----
 
-# How to connect ICs between them

slides/lectures/resources/signals/VCC1_smaller_VCC2.svg

@@ -0,0 +1,191 @@
+---
+layout: two-cols
+---
+
+# Why is the output not ideal?
+
+
+### The two corresponding voltage output levels are affected by:
+
+- power supply voltage
+- output current 
+- temperature 
+- variations in the manufacturing process 
+
+:: right ::
+
+<br>
+<br>
+<br>
+<br>
+
+
+ <img src="./d_output.svg" class="rounded">
+
+---
+layout: two-cols
+---
+
+# ICs same voltage
+
+
+### Usually will work as is
+
+- usually, they will be compatible
+- conditions:
+> V_OH_transmiter > V_IH_receiver
+
+<br>
+
+> V_OL_transmiter < V_IL_receiver
+
+:: right ::
+
+ <img src="./ICs_same_voltage.svg" class="rounded h 80">
+
+---
+layout: two-cols
+---
+
+# VCC1 > VCC2
+
+
+### Might work, might produce magic smock
+
+- if
+> V_OH_transmiter > VCC_receiver 
+
+<b>  PROBLEM </b>
+
+### Solutions:
+- level shifter
+- resistor divider / voltage limiter 
+
+Examples:
+
+<a href="https://www.optimusdigital.ro/ro/interfata-convertoare-de-niveluri/181-translator-de-nivel-bidirectional-cu-4-canale.html" title="Bi-Directional Level Shifter with 4 Channels">
+    Bi-Directional Level Shifter (4 Channels)
+</a>
+
+<br>
+
+<a href="https://www.tme.eu/en/details/tp240610/development-kits-accessories/total-phase/level-shifter/">
+    Level Shifter Multi-Channel
+</a>
+
+
+<br>
+
+<a href="https://www.adafruit.com/product/395">
+   8 Channels Level Shifter
+</a>
+
+
+
+
+:: right ::
+
+ <img src="./vcc1_larger_vcc2.svg" class="rounded h 80">
+ 
+
+---
+layout: two-cols
+---
+
+# VCC1 < VCC2
+
+
+### Might work
+
+- if
+> V_CC_transmiter close to VIH_receiver 
+
+<b>  Might work in an intermittent mode - hard to debug!</b>
+
+### Solutions:
+- level shifter
+- resistor divider / voltage limiter 
+
+Examples:
+
+<a href="https://www.optimusdigital.ro/ro/interfata-convertoare-de-niveluri/181-translator-de-nivel-bidirectional-cu-4-canale.html" title="Bi-Directional Level Shifter with 4 Channels">
+    Bi-Directional Level Shifter (4 Channels)
+</a>
+
+<br>
+
+<a href="https://www.tme.eu/en/details/tp240610/development-kits-accessories/total-phase/level-shifter/">
+    Level Shifter Multi-Channel
+</a>
+
+
+<br>
+
+<a href="https://www.adafruit.com/product/395">
+   8 Channels Level Shifter
+</a>
+
+
+
+
+:: right ::
+
+ <img src="./vcc1_smaller_vcc2.svg" class="rounded h 80">
+
+
+---
+layout: two-cols
+---
+
+# Why Pull-Down R
+
+- Without pull-down – when the button is not pressed, it leaves the input pin floating.
+- The second design ensures that the voltage level has a well-defined state, regardless of the button's state.
+- R1 is called a "pull-down" resistor.
+
+:: right ::
+
+<br>
+<br>
+<br>
+<br>
+
+
+ <img src="./pull_down.png" class="rounded" h="50">
+
+---
+layout: two-cols
+---
+
+# Why Pull-Up R
+
+- Same reasoning
+- R1 is called a "pull-up" resistor.
+
+##Obs:
+- most microcontrollers have at least a pull-up resistor incorporated on GPIOs - that can be activated in software
+- some have both pull-up and pull-down
+- typically, these are sized for a 50 - 10 nA current consumption
+
+
+:: right ::
+
+<br>
+<br>
+<br>
+<br>
+
+
+ <img src="./pull_up.png" class="rounded" h="50">
+
+---
+
+# Notes on output pins
+
+- most microcontrollers have a limit of around 10mA per output PIN
+- ! do not connect an LED without a resistor in series )to limit the current) 
+- ! do not connect a motor / any type of inductive load
+
+## Solutions:
+- use a transistor
+- use an IC with incorporated Darlinghtons (eg: ULN2003)