diff -r 8a7f8272516c -r 644a6106d712 brewpanel/README
--- a/brewpanel/README	Sun Nov 08 22:20:42 2015 +0100
+++ b/brewpanel/README	Sat Nov 14 16:52:33 2015 +0100
@@ -4,20 +4,32 @@
 All commands are 16 bits unsigned integers.
 
      D15 D14 D13 D12 D11 D10 RS  R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
-      0   0   0  LC2 LC1 LC0  0   0   0   0   0   0   0   0   0   1	Screen clear, home
-      0   0   0  LC2 LC1 LC0  0   0   0   0   0   0   0   0   1   .	DDRAM AD=0, return
-      0   0   0  LC2 LC1 LC0  0   0   0   0   0   0   0   1  I/D  S	Set moving direction of cursor
-      0   0   0  LC2 LC1 LC0  0   0   0   0   0   0   1   D   C   B	Display Cursor Blink on/off
-      0   0   0  LC2 LC1 LC0  0   0   0   0   0   1  S/C R/L  .   .	Remove cursor and display
-      0   0   0  LC2 LC1 LC0  0   0   0   0   1   DL  N   F   .   .	Set DL display line font
-      0   0   0  LC2 LC1 LC0  0   0   0   1				Set CGRAM send/receive data
-      0   0   0  LC2 LC1 LC0  0   0   1					Set DDRAM sebd/receive data
-      0   0   0  LC2 LC1 LC0  0   1   BF				Busy Flag
-      0   0   0  LC2 LC1 LC0  1   0					Write data to CGRAM or DDRAM
-      0   0   0  LC2 LC1 LC0  1   1					Read data from CGRAM or DDRAM
-      0   0   1  LC2 LC1 LC0  0   0   0   0   0   0   0   0   0   .	LED on/off
-      0   1   0  LC2 LC1 LC0  0   0   0   0   0   0   0   0   0   .	Buzzer on/off
+      0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0	Null command to get keys state.
+     LC2 LC1 LC0  0   0   0   0   0   0   0   0   0   0   0   0   1	Screen clear, home
+     LC2 LC1 LC0  0   0   0   0   0   0   0   0   0   0   0   1   .	DDRAM AD=0, return
+     LC2 LC1 LC0  0   0   0   0   0   0   0   0   0   0   1  I/D  S	Set moving direction of cursor
+     LC2 LC1 LC0  0   0   0   0   0   0   0   0   0   1   D   C   B	Display Cursor Blink on/off
+     LC2 LC1 LC0  0   0   0   0   0   0   0   0   1  S/C R/L  .   .	Remove cursor and display
+     LC2 LC1 LC0  0   0   0   0   0   0   0   1   DL  N   F   .   .	Set DL display line font
+     LC2 LC1 LC0  0   0   0   0   0   0   1				Set CGRAM send/receive data
+     LC2 LC1 LC0  0   0   0   0   0   1					Set DDRAM sebd/receive data
+     LC2 LC1 LC0  0   0   0   0   1   BF				Busy Flag
+     LC2 LC1 LC0  0   0   0   1   0					Write data to CGRAM or DDRAM
+     LC2 LC1 LC0  0   0   0   1   1					Read data from CGRAM or DDRAM
+     LC2 LC1 LC0  0   0   1   0   0   .   .   .   .   .   .   .   .	LEDs, buzzer on/off
+     LC2 LC1 LC0  0   1   0   0   1   0   0   0   0  Up  Dwn Ret Ent	Keys pressed
  
 
 LC2 LC1 LC0 are the device index, 0..7
+LEDs:	DB0	Control LED on thermferm panels
+	DB1	HLT heater
+	DB2	MLT heater
+	DB3	MLT pump/mixer
+	DB7	Buzzer
 
+The thermferm or brewco units are leading, they send data and get a reply.
+The sending data will mostly be display data mixed with LEDs. The replies
+will mostly be the current key states, even if not changed. If the leading
+program just wants key states, it should send a 0 to the brewpanel.
+
+