Merge pull request #7 from Flenk008/patch-2

Update research.md

1 files changed, 47 insertions, 1 deletions

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@@ -98,7 +98,7 @@ int main() {
   setup();
   while(1) loop();
 }
-
+```
 # Generating audio signals
 
 In order to generate sound for this project, a few posibilities exist (see chapters below)
@@ -204,3 +204,49 @@ There are a lot of ways of creating tiles and sprites for pixel art. Underneath
 | Asesprite     | https://www.aseprite.org/                                        |Yes   | pixel art        |
 
 
+# Input 
+The playable character has 4 actions that it can perform:
+-	movement on the x-axis
+-	jump 
+-	ability / use
+
+To control these actions there has to be at least 4 inputs. 
+These can either be a button or joystick. 
+The actions can be done as follows:
+
+| Action | Button |	Joystick |
+| ------ | ------ | -------- |
+| Movement x-axis| 	x | x |
+| Jump |	x	 |  |
+| Ability | 	x	|  |
+
+## Handling
+A joystick requires an ac input port. 
+A button can use both a ac and dc input port.
+So the hardware needs to have both an ac input and a dc input, if a button and a joystick are used. 
+The input can be handled by either the FPGA(stm32) or microcontroller (STM32).
+The microcontroller has the possibility to run multiple task simultaneously if needed.
+The FPGA code contains multiple entities.
+Data transfer between these entities takes at least one clock cycle.
+If there are multiple entities the delay will increase and decreases the playability of the game.
+
+## Conlcusion
+For gameplay reasons it is recommended to have the input handling as close as possible to the game logic unit.
+This will decrease the delay between the user-input and onscreen gameplay. 
+
+# Microcontroller FGPA communication
+
+The hardware of the game consist out of a microcontroller(stm32) and a FPGA(basys3). The hardware components needs to communicate with each other. For this a protocol is needed.
+See table 1 for a comparison of possible protocols:
+| Protocol |	UART |	I2C	| SPI |
+| -------- | ----- | ---- | --- |
+|Number of lines |	1/2 |	2 |	4 |
+|Duplex	| Half-duplex	| Half-duplex	| Full-duplex |
+|Data transfer speed |	Upto 5mbps | Upto 3.4Mbps – 5Mbps	| Default at 50Mbps. Upto 100Mbps |
+|Speed	| Slowest |	Faster than UART | Fastest |
+
+There are only two devices that has to be connected. Complexity and master/slave amount are not relevant for this purpose. 
+If there are multiple entities the delay will increase and decreases the playability of the game.
+
+## Conlcusion
+It is recommended that SPI will be the communication protocol because of the data transfer speeds. The is a lot of data transfer between the microcontroller and FPGA.