Slave mode for Inkplate 6 by e-radionica.com
Slave mode is uploaded to each Inkplate 6. It enables you to use the board
without reprogramming. You just need to send commands via UART and it will
show contents on its screen. 
You can send commands via USB port or by directly connecting to ESP32 TX and RX pins.

Don't forget you need to send #L(1)* after each command to show it on the display (equal to display.display()). 

Settings are:
115200 baud, standard parity, ending with \n\r

echo:			#?*
Check if the Inkplate receives commands on UART
response:		OK

drawPixel:		#0(XXX,YYY,CC)*
XXX - X coordinate (with leading zeros)
YYY - Y coordinate (with leading zeros)
CC - Color (with leading zeros)
example #0(001,005,04)*

drawLine:		#1(XXX,YYY,III,JJJ,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
III - End x coordinate (with leading zeros)
JJJ - End y coordinate (with leading zeros)
CC - Color (with leading zeros)
example #1(001,004,010,123,01)*

drawFastVLine:		#2(XXX,YYY,LLL,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
LLL - Length of line (with leading zeros)
CC - Solor (with leading zeros)
example #2(142,425,040,05)*

drawFastHLine:		#3(XXX,YYY,LLL,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
LLL - Length of line (with leading zeros)
CC - Color (with leading zeros)
example #3(123,014,100,03)*

drawRect:		#4(XXX,YYY,WWW,HHH,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
WWW - Width of rect. (with leading zeros)
HHH - Height of rect. (with leading zeros)
CC - Color (with leading zeros)
example #4(123,014,050,010,01)*

drawCircle:		#5(XXX,YYY,RRR,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
RRR - Radius of circle (with leading zeros)
CC - Color (with leading zeros)
example #5(050,100,040,01)*

drawTriangle:		#6(XX1,YY1,XX2,YY2,XX3,YY3,CC)*
XX1 - X coordinate of first corner (with leading zeros)
YY1 - Y coordinate of first corner (with leading zeros)
XX2 - X coordinate of second corner (with leading zeros)
YY2 - Y coordinate of second corner (with leading zeros)
XX3 - X coordinate of third corner (with leading zeros)
YY3 - Y coordinate of third corner (with leading zeros)
CC - Color (with leading zeros)
example #6(250,250,100,400,375,450,04)*

drawRoudRect:		#7(XXX,YYY,WWW,HHH,RRR,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
WWW - Width of rect. (with leading zeros)
HHH - Height of rect. (with leading zeros)
RRR - Radius (with leading zeros)
CC - Color (with leading zeros)
example #7(123,014,050,010,005,00)*

fillRect:		#8(XXX,YYY,WWW,HHH,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
WWW - Width of rect. (with leading zeros)
HHH - Height of rect. (with leading zeros)
CC - Color (with leading zeros)
example #8(123,014,050,010,01)*

fillCircle:		#9(XXX,YYY,RRR,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
RRR - Radius of circle (with leading zeros)
CC - Color (with leading zeros)
example #9(050,100,040,01)*

fillTriangle:		#A(XX1,YY1,XX2,YY2,XX3,YY3,CC)*
XX1 - X coordinate of first corner (with leading zeros)
YY1 - Y coordinate of first corner (with leading zeros)
XX2 - X coordinate of second corner (with leading zeros)
YY2 - Y coordinate of second corner (with leading zeros)
XX3 - X coordinate of third corner (with leading zeros)
YY3 - Y coordinate of third corner (with leading zeros)
CC - Color (with leading zeros)
example #A(250,250,100,400,375,450,04)*

fillRoudRect:		#B(XXX,YYY,WWW,HHH,RRR,CC)*
XXX - Start x coordinate (with leading zeros)
YYY - Start y coordinate (with leading zeros)
WWW - Width of rect. (with leading zeros)
HHH - Height of rect. (with leading zeros)
RRR - Radius (with leading zeros)
CC - Color (with leading zeros)
example #B(123,014,050,010,005,00)*

print:			#C("STRING")*
STRING - Text/Strig coded in HEX Char (example: HELLO WORLD would be coded like 48454c4c4f20574f524c44, where 48 means 0x48 which is H in ASCII table)
example for HELLO WORLD #C("48454c4c4f20574f524c44")*

setTextSize:		#D(NN)*
NNN - Text scaling (with leading zeros)
example #D(02)*

setCursor:		#E(XXX,YYY)*
XXX - X position of text cursor (with leading zeros)
YYY - Y position of text cursor (with leading zeros)
example #E(002,010)*

setTextWrap:		#F(T/F)*
T - True if enable text wraping
F - False if disable text wraping
example #F(T)* or #F(F)*

setRotation:		#G(RRR)*
RRR - Sets rotation (0-3, where each increment rotates whole screen by 90 deg)
example #G(003)*

drawBitmap:		#H(XXX,YYY,"PATH")*
XXX - X position of bitmap on display
YYY - Y position of bitmap on display
PATH - path to bitmap image on SD card
example: #H(000,000,"/bitmapName.bmp")*
response:		#H(1)* - Image loaded succesfully
			#H(0)* - Image load failed
			#H(-1)* - SD Card Init Error

setDisplayMode:		#I(D)*
D - Display Mode (D = 3 -> 3 bit mode, D = 1 -> 1 bit mode)
example: #I(3)* or #I(1)*

getDisplayMode:		#J(?)*
Response:		#J(1)* - 3 bit mode
			#J(0)* - 1 bit mode

clearDisplay:		#K(1)*

display:		#L(1)*

partialUpdate:		#M(YY1, XX2, YY2)*
YY1 - Start Y position of part of the screen that will be updated
XX2 - End X position of part of the screen that will be updated
YY2 - End Y position of part of the screen that will be updated
example: #M(005,400,040)*

readTemperature:	#N(?)*
response:		#N(23)* - 23 Celsius degrees

readTouchpad:		#O(P)*
P - Name of pad that needs to be read (1, 2 or 3)
resposne:		#O(1)* for high state of pad or #O(0)* for low state of pad

readBattery:		#P(?)*
response:		#P(3.65)* - Measured voltage on battery is 3.65VDC

panelSupply(einkOff/on):#Q(S)*
S - State of panel power supply (S = 1 -> panel has power supply, S = 0 -> panel power supply has benn turned off)

getPanelState:		#R(?)*
response:		#R(1)* - panel has power supply or #R(0)* - panel supply has been turned off