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libraries/ssd1306/examples/vga/README.md

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+# VGA SUPPORT
+
+## Introduction
+
+Vga support have 2 modes:
+
+ * host mode (works directly from your sketch)
+ * client mode (vga code works on separate microcontroller)
+
+In the first case the atmega328p controller executes sketch application and drives vga monitor. The vga code uses
+all 3-timers, so standard `micros()` and `delay()` functions do not work in this mode! `millis()` still works, but
+it looses precision (it updates only each 16 milliseconds). The code needs 3 timers for the following reasons: 
+*timer0* to fix jitter effects, *timer1* to drive V-Sync signal, and *timer2* to drive H-Sync signal. If you want
+to use `delay()`, please call `ssd1306_vga_delay()` instead.
+
+In client mode, the controller executes sketch application only, so, all standard functions are available. The vga code
+runs on separate microcontroller connected with your EVK via UART line. So in client mode, the ssd1306 library part needs
+only UART to send commands to the second controller, which runs vga_server_demo; and you are free to use any pins you need,
+except UART pins.
+
+## Supported controllers
+
+ * Only Atmega328p is supported now in host and client modes
+ * Any controller can be supported in client mode in future.
+
+## Connecting Atmega328p to D-Sub
+
+There are a lot of articles on D-Sub pinout over Internet. You need to connect GND, V-Sync, H-Sync, R, G, B
+to D-Sub connector via resistors. ssd1306 library uses the following pins on Atmega328p:
+
+ * D3    - H-SYNC
+ * D10   - V-SYNC
+ * D14 (A0) - BLUE
+ * D15 (A1) - GREEN
+ * D16 (A2) - RED
+ * D17/D18/D19 cannot be used for your sketch (this is the cost of optimization).
+