'Program SONY_RX.BAS

'Reads signals from a Sony IR remote control,
'and returns the button code in the variable IR_But.
'the device code in the variable IR_DEV, 

'The infrared receiver module used is the Sharp IS1U60.

'The infrared receiver module for this experiment should, 
'be a type that is set for a 40kHz carrier frequency. 
'If another type is used. some reduction in range may be noticed. 

'The remote control used, may be either a Sony manufactured unit,
'or one of the universal remotes that can be configured for Sony equipment. 
'This is important since we are dealing with a specific signal protocol.

'With Sony’s SIRC specification, a start pulse is initially sent to
'indicate the beginning of a frame of data. This pulse is approx 2.4 ms in length. 
'Following this, are 5-bits of data, which represent the DEVICE code, 
'which signifies the target device (TV, VCR, etc.). 
'Then an additional 7-bit BUTTON code 
'Data bits are sent with the most significant bit first (MSB).

	Include "Modedefs.Bas"
	Define 	OSC		4		' Set Xtal Frequency

' ** Declare the Variables **
	Header		Var	Word		' Header pulse length
	Packet		Var	Word		' 12-bit IR information
	P_Val		Var	Byte		' The bit length 60us = 0, 120us = 1
	IR_But		Var	Byte		' The BUTTON code returned
	IR_Dev		Var	Byte		' The DEVICE code returned
	Sony_LP		Var	Byte		' Temporary loop variable
	Red_LED		Var	PortA.0		' Assign the green LED to this pin
	Green_LED	Var	PortA.1		' Assign the red LED to this pin
	IR_Sensor	Var	PortA.2		' Assign the IR Sensor to this pin

' ** THE MAIN PROGRAM LOOP STARTS HERE **

Again:	Low Green_LED:Low Red_LED		' Extinguish both LED's
	Gosub IRIN				' Receive an IR signal
	If IR_Dev=255 then goto Again		' Check if header was valid
	Serout PortA.3,N9600,[IR_Dev,IR_But]	' Transmit the 2 bytes serially
	If IR_Dev<>0 then goto Again		' If not a TV DEVICE code then look again
	If IR_But=116 then High Green_LED	' If channel up, then light the green LED
	If IR_But=117 then High Red_LED		' If channel down, then light the green LED
	Pause 100				' Delay for 100ms
	Goto Again				' Do it forever

' Receive a signal from a Sony remote control,
' and return with the 7-bit BUTTON code in the variable IR_BUT,
' and the 5-bit DEVICE code in the variable IR_DEV.
' If a header was not detected then IR_DEV and IR_BUT will hold 255
IRIN:	IR_Dev=255:IR_But=255
	Pulsin PortA.2,0,Header			' Measure the header length.
        If Header < 200 then Return   		' Verify a good header   		
        If Header > 270 then Return       	' If not valid then exit

' Receive the data bits (MSB first), and convert them into a 12-bit packet
' A one should return approx 120, actual timing is 1200us
' A zero should return approx 60, actual timing is 600us
' We split the difference and say that < 90 is a 0 and >= 90 is a 1
' These values are for use with a 4mHz crystal
	For Sony_Lp=0 to 11			' Do 12-bits
	Pulsin PortA.2,0,P_Val			' Receive the IR bit pulse
	If P_Val >= 90 then 			' If it's >= 90 then we've received a 1
	Packet.0[Sony_Lp]=1			' So set the appropriate bit of PACKET
	Else 					' Else
	Packet.0[Sony_Lp]=0			' Clear the appropriate bit of PACKET 
	Endif
	Next 					' Close the loop

' Split the 7-bit BUTTON code, and the 5-bit DEVICE code
	IR_But=Packet & %01111111		' Mask the 7 BUTTON bits
	IR_Dev=(Packet >>7) & %00011111		' Move down and mask, the 5 DEVICE bits
	Return