'DMX Controller
'Version: 0.1
'Creation Date: 1/14/07
'Modified Date: 1/14/07
'Revisions:
'	0.1	1/14/07	Initial revision based on weeks of tinkering and protocol analysis.
'
'Notes:
'This was made to work on a PIC 16F628 chip.
'For using a 20MHz resonator...
'Set the DEFINE OSC 20 in the PBP program to tell PBP that it will be running faster than 4MHz.
'In EPICWin, uncheck Options > Update Configuration.  This stops EPIC from changing back to INTRC(IN) before programming.
'Then set the Oscillator option HS for external resonator.

DEFINE OSC 20	'Set oscillator in MHz
RCSTA.7= 1	'Enable UART

chan1 var byte
chan2 var byte
chan3 var byte
chan4 var byte
chan1 = 0
chan2 = 85
chan3 = 170
chan4 = 255
ch1toggle var bit
ch1toggle = 0
ch2toggle var bit
ch2toggle = 0
ch3toggle var bit
ch3toggle = 0
ch4toggle var bit
ch4toggle = 0

'setup hardware uart rx/tx @ 250kbaud, for DMX
DEFINE	HSER_RCSTA 90h	'90hex: enables rx, even though we're not doing that here.
DEFINE	HSER_TXSTA 65h	'65hex: 9-bit, tx enable, BRGH high, First bit is 0 for the Start Bit.
DEFINE	HSER_BAUD 250000	'250Kbps Baud
DEFINE	HSER_SPBRG 4 	'Baud Rate Generator Register Value (0 to 255!), This seems to make each bit 4us wide which is how wide DMX bits are. 

LIB_dmx_out:

'This just makes all 4 channels ramp up and down for demonstration purposes.
Sequencing:
Pause 5
if chan1 = 255 then ch1toggle = 0
if chan1 = 0 then ch1toggle = 1
if ch1toggle = 0 then chan1 = chan1 - 1
if ch1toggle = 1 then chan1 = chan1 + 1

if chan2 = 255 then ch2toggle = 0
if chan2 = 0 then ch2toggle = 1
if ch2toggle = 0 then chan2 = chan2 - 1
if ch2toggle = 1 then chan2 = chan2 + 1

if chan3 = 255 then ch3toggle = 0
if chan3 = 0 then ch3toggle = 1
if ch3toggle = 0 then chan3 = chan3 - 1
if ch3toggle = 1 then chan3 = chan3 + 1

if chan4 = 255 then ch4toggle = 0
if chan4 = 0 then ch4toggle = 1
if ch4toggle = 0 then chan4 = chan4 - 1
if ch4toggle = 1 then chan4 = chan4 + 1



RCSTA.7= 0	'disable UART
Low PORTB.2	'low for frame start sync, Break
pauseus 120	'88us min required, 120us is safer.
High PORTB.2 	'high for mark after break
pauseus 8		'8usec min required
RCSTA.7= 1	'Enable UART

HSEROUT [0]	'Start Code. Already includes the start bit.
pauseus 36		'let the serial data finish
RCSTA.7= 0
High PORTB.2 	'high for two stop bits and MTBF
pauseus 8
RCSTA.7= 1

HSEROUT [chan1]	'Channel 1
pauseus 36		'let the serial data finish
RCSTA.7= 0
High PORTB.2 	'high for two stop bits and MTBF
pauseus 8
RCSTA.7= 1

HSEROUT [chan2]	'Channel 2
pauseus 36		'let the serial data finish
RCSTA.7= 0
High PORTB.2 	'high for two stop bits and MTBF
pauseus 8
RCSTA.7= 1

HSEROUT [chan3]	'Channel 3
pauseus 36		'let the serial data finish
RCSTA.7= 0
High PORTB.2 	'high for two stop bits and MTBF
pauseus 8
RCSTA.7= 1

HSEROUT [chan4]	'Channel 4
pauseus 36		'let the serial data finish
RCSTA.7= 0
High PORTB.2 	'high for two stop bits and MTBF
pauseus 8
RCSTA.7= 1


Pause 5
Goto LIB_dmx_out