'Output a triangle wave which is saved in XRAM and output over DMA to DAC B Channal 0


$regfile = "xm128a1def.dat"
$crystal = 32000000                                         '32MHz
$hwstack = 64
$swstack = 40
$framesize = 40

Config Osc = Disabled , 32mhzosc = Enabled                  '32MHz
'configure the systemclock
Config Sysclock = 32mhz , Prescalea = 1 , Prescalebc = 1_1
Config Priority = Static , Vector = Application , Lo = Enabled

Config Com5 = 57600 , Mode = Asynchroneous , Parity = None , Stopbits = 1 , Databits = 8       'Portf.2 and Portf.3 is COM7
Open "COM5:" For Binary As #1

Print #1 ,
Print #1 , "Start output of triangle wave from XRAM over DMA to DAC B Channel 0"


Dim Memory_address As Word


' Demoboards like XPLAIN has a 64 MBit SDRAM (MT48LC16M4A2TG) which is 8 MByte, it is connected in 3 port, 4 bit databus mode
' http://www.micron.com/products/ProductDetails.html?product=products/dram/sdram/MT48LC16M4A2TG-75
' in the PDF of the SDRAM you can see it is connected as 16 Meg x 4. Refreshcount is 4K and the row address is A0-A11, column addressing is A0-A9
' SDRAM = SYNCHRONOUS DRAM
Config Xram = 3port , Sdbus = 4 , Sdcol = 10 , Sdcas = 3 , Sdrow = 12 , Refresh = 500 , Initdelay = 3200 , Modedelay = 2 , Rowcycledelay = 7 , Rowprechargedelay = 7 , Wrdelay = 1 , Esrdelay = 7 , Rowcoldelay = 7 , Modesel3 = Sdram , Adrsize3 = 8m , Baseadr3 = &H0000
' the config above will set the port registers correct. it will also wait for Ebi_cs3_ctrlb.7
' for all other modes you need to do this yourself !

$xramsize = 8000000                                         ' 8 MByte

' XRAM Start direct after the SRAM range of a XMEGA which is after 16KByte so the first XRAM address is 16384
' The maximum XRAM is in case of 8MByte SDRAM  = 8000000 - 16384 = 7983616 Byte
Dim X(1000000) As Xram Word                                 '7,98 MByte (big mem must be XRAM)
' Restriction : variables placed outside 64KB memory may not be passed to SUB functions because addressing outside of 64KByte will not fit in a word !


Dim I As Word
Dim Y As Word


For I = 1 To 4096                                           'From 0V .....3.3Volt (with Reference = avcc)
  X(i) = I
Next

Y = 4096
For I = 4097 To 8192
  Decr Y
  X(i) = Y
Next

Memory_address = Varptr(x(1))                               'We want to know now what is the Address of X(49152)
Print #1 , "XRAM Adress =  " ; Memory_address

I = X(4096)
Print #1 , "I=" ; I


Config Tcc0 = Normal , Prescale = 1
Tcc0_per = 128                                              '31 --> 32MHz/32 = 1MHz

Config Event_system = Dummy , Mux0 = Tcc0_ovf               'TCC 0 overflow --> Event Channel 0

Config Dacb = Enabled , Io0 = Enabled , Channel = Single , Trigger_ch0 = Enabled , Event_channel = 0 , Reference = Avcc , Interval = 64 , Refresh = 64
'DAC B Channel 0 is triggered by Event Channel 0

' DMA Interrupt
Config Dma = Enabled , Doublebuf = Disabled , Cpm = Rr      ' enable DMA, Double Buffer disabled

' DMA Channel 0 is used here
Config Dmach0 = Enabled , Burstlen = 2 , Chanrpt = Enabled , Tci = Off , Eil = Off , Singleshot = Enabled , _
 Sar = Transaction , Sam = Inc , Dar = Burst , Dam = Inc , Trigger = &H25 , Btc = 16384 , Repeat = 0 , Sadr = Varptr(x(1)) , Dadr = Varptr(dacb_ch0datal)

' Trigger = &H25 (DAC B Base Level Trigger) + Channel 0 = &H00 --> &H25
' Burstlen is 2 byte because the DAC output value is a 12-Bit value you need to transfer 2 byte
' Source address (the array) is incremented until all bytes transfered (16384 byte)
' Destination address (DAC B Channel 0) is incremented once to transfer the low byte and high byte of the 12-bit value
' BTC = 16384 BYTE (needed to transfer the 8192 word)
' Reapeat = 0 --> repeat forever



Do

Loop

End                                                         'end program

 

' DMA Channel 0 is used here
Config Dmach0 = Enabled , Burstlen = 2 , Chanrpt = Enabled , Tci = Off , Eil = Off , Singleshot = Enabled , _
 Sar = Transaction , Sam = Inc , Dar = Burst , Dam = Inc , Trigger = &H25 , Btc = 16384 , Repeat = 0 , Sadr = Varptr(x(1)) , Dadr = Varptr(dacb_ch0datal)