TerSer/README.md

# TerSer

A much smaller and more efficient serial library than Arduinos Serial by [Didel](https://www.didel.com). 
Use one include file to replace the Serial.print from Arduino library.

**Table of Contents**  
[What is the problem with Arduino Serial.print ?](#what-is-the-problem-with-arduino-serialprint-)  
[Example comparison between Didel TerSer and Arduino Serial](#example-comparison-between-didel-terser-and-arduino-serial)  
[Using tabular data](#using-tabular-data)  
[TerSer Limitations](#terser-limitations)  
[Code size and timing comparison](#code-size-and-timing-comparison)  
[How to switch from Arduino Serial](#howto_switch)

### What is the problem with Arduino Serial.print ?
Serial.print is is most of the time used as a debugging tool, and with limited resources it is even more important to have the most lighweight solution for this task. 

Also when Serial debugging is used to display sensor values, as shown next, suppressing non significative zeros is not adequate for tabular data, specially when the screen is scrolling.
Serial.print is a good example of the "Law of instrument":
One just uses a bad but widely available tool, and is not willing to find or invent a better one.

We propose to use a compact C portable library. Compatibility with an Oled display is a further plus. The SerTerm.h and OledTerm.h are demonstrated on the popular Arduino environment, but it is just plain C.

It is admittedly very convenient to just use Serial.print(var); since it doesn't require you to specify the type of variable. Though when trying for example to output data in tabular style the processor needs to know the data type used so that it can reserve the adequate space for it in its output. It might seem like a big inconvenience to specify the data type with any statement that outputs data over serial but then again for debugging purposes it makes perfectly sense in terms of speed AND size of the resulting code. By the same reasons we also do not use a buffer as it is needed only in specific situations.
The TerSer.h offer the choice of 4 print format for numbers. Signed variables have a + or – sign in front. 
| Normal (moz=0) | Spaces (moz=1) | Zeros (moz=2) | Compact (moz=3) | Serial.print |
| -------------- | -------------- | -------------- | -------------- | -------------- |
| ![moz0](docs/images/tab_moz0.png?raw=true "Example moz=0") | ![moz1](docs/images/tab_moz1.png?raw=true "Example moz=1") | ![moz2](docs/images/tab_moz2.png?raw=true "Example moz=2") | ![moz3](docs/images/tab_moz3.png?raw=true "Example moz=3") | ![Aserial](docs/images/tab_arduino_serial.png?raw=true "Example Arduino Serial.print") |

<a name="howto_switch"/>
### How to switch from Arduino Serial
If you are looking for a drop-in replacement for Arduino Serial with a smaller memory footprint follow the procedure outlined below to quickly switch your project to Didel TerSer:
* Add **#include <TerSer.h>** at the top of your sketch or select the library from your Arduino IDE (*Sketch* | *Include Library*)
* Use the either the library function names we provide or define your own function names, for example:
`#define Serialprint(x) Text(x)`
* Search for all occurences or `Serial.print` and replace with `Serialprint`
Voila, you have switched to TerSer and enjoy smaller footprint at less mcu cycles

#### Function aliasing
If you do not like our function/method names, feel free to define names that suit your tastes with i.e.:
`#define Serialprint(x) Text(x)`
`#define Serialprint(x,BIN) Bin8(x)`
`#define Serialprint(x,BIN) Bin16(x)`
`#define Serialprint(x) Dec16(x)`
etc.

### TerSer Installation 

<a name="example_comparison"/>
### Example comparison between Didel TerSer and Arduino Serial
| TerSer | Output TerSer | Output Serial | Arduino Serial |
| ------------- | ------------- | ------------- | ------------- |
| Car('Z'); | Z | Z | Serial.print('Z'); |
| Text("Test"); | Test | Test | Serial.print("Test"); |
| Bin16(v16); | 0000010001100000 | 10001100000 | Serial.print(v16,BIN); |
| Hex16(v16); | 08c0 | 8c0 | Serial.print(v16,HEX); |
| Dec16(v16); | 1120 | 1120 | Serial.print(v16); |
| Dec16(v16b); | 0020  or   20 | 20 | Serial.print(v16b); |
| Dec16(v16s); | +  20 or +0020 | 20 | Serial.print(v16s); |
| Dec16(-v16s); | 20 or -0020 | -20 | Serial.print(-v16s); |

*uint16_t  v16=1120; uint16_t  v16b=20;  int16_t  v16s=20;*

### Using tabular data

Filling the non significative digits with zero or space is a general options, named ShowZ(); and HideZ(); 

The Tab(nn); function, allows to align data of different types.
e.g. Table next had to be written:
Text ("Mode HideZ();") SetTab(15);  
  Text ("Mode ShowZ();");NL();
HideZ();Dec8s(3);    SetTab(15);
  ShowZ();Dec8s(3); NL();
. . .

![Table1](docs/images/tabTable.png?raw=true "Example Table 1")

It is up to you to add functions like TextNL();
if you need to keep your Serial.println() habits.

### TerSer Limitations
TerSer does not print floating point numbers. 
The may happen some day with one more file to import, e.g. names TerFloat.h.

Dec8(); and Dec16(); use a tricky macro to recognize the signed or unsigned data type. The parameter must be a single variable, e.g. Dec8(var); Dec8(var+2); will give wrong results.
Code will be shorter and there will be no limitation if you use Dec8u(any unsigned expr); and 
Dec8s(any signed expr);, same of course Dec16u(); and Dec16s();

### Code size and timing comparison
Code size has been obtained by calling one function at a time, compiler under the usual -0s mode. Size is the difference with the empty file size. TerSer.h can of course be used with setup() and loop(). It add the ~300 bytes Arduino initializations.
Execution time has been measured with a Nop replacing the SendCar function. The time depends on the baud rate, ~1 ms per character displayed at 9600 bits/s.