CONFIG VPORT - Revision history

Admin at 18:32, 17 January 2017

2017-01-17T18:32:32Z

Admin at 18:32, 17 January 2017

2017-01-17T18:32:16Z

Admin at 13:22, 4 February 2014

2014-02-04T13:22:26Z

Admin: Created page with "= Action = Maps an XMEGA port to a virtual port.
2013-02-08T11:59:53Z

Created page with "= Action = Maps an XMEGA port to a virtual port. </spa..."

New page
= Action =

Maps an XMEGA port to a virtual port.

 

 

= Syntax =

CONFIG VPORT0 = port  [, VPORT1=port, VPORT2=port, VPORT3=port]

 

 

= Remarks =
<div style="padding: 0px; margin: 0px 0px 0px 4px;">
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VPORT

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There are 4 virtual port registers. When setting up these registers, you need to use VPORTx, where X is 0,1,2 or 3, indicating the virtual port.

The virtual port itself is accesed via it's registers PORTy, PINy and DDRy where Y is a 0,1 ,2 or 3.

The normal ports have named like PORTA, PORTB, etc.

A virtual port will access the same port but using a different register.

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port

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The last letter of the real port name. For example A for PORTA, B for PORTB, C for PORTC etc.

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</div>
 

All ports in the Xmega are located in the extended address area. This space can only be accessed with instructions like LDS,STS, LD and ST.

Special bit instructions only work on the lower IO-registers.

 

Xmega example :

again:

Lds r24, PINA   ; read port input value

sbrs r24,7       ; skip next instruction if bit 7 is set (1)

rjmp again       ; try again

 

Now the same code for a normal AVR

again:

sbis PINA,7      ; skip if pina.7 is set

rjmp again

 

Not only less code is required, but the LDS takes 3 cycles

 

With the virtual mapping, you can access any PORT register (PORT,PIN and DDR) via it's virtual name PORT0, PIN0 or DDR0.

Since there are 4 virtual mapping registers, you can define PORT0, PORT1, PORT2 and PORT3.

When you write to PORTn, the compiler can use the smaller/quicker code.

 

Devices like graphical LCD can benefit from this.

 

 

 

= See Also =

[[CONFIG PORT|CONFIG PORT]]

 

 

= Example =

 <source lang="bascomavr">
'-----------------------------------------------------------------
' (c) 1995-2010, MCS
' Mapping Real Ports to Virtual Ports.bas
' This sample demonstrates mapping ports to virtual ports
' based on MAK3's sample
'-----------------------------------------------------------------

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

'include the following lib and code, the routines will be replaced since they are a workaround
$lib "xmega.lib"
$external _xmegafix_clear
$external _xmegafix_rol_r1014

'first enable the osc of your choice
Config Osc = Enabled , 32mhzosc = Enabled

'configure the systemclock
Config Sysclock = 32mhz , Prescalea = 1 , Prescalebc = 1_1

Config Com1 = 19200 , Mode = Asynchroneous , Parity = None , Stopbits = 1 , Databits = 8

Print "Map VPorts"
'map portD to virtual port0, map portE to virtual port1, map portC to virtual port2
'map portR to virtual port 3
Config VPort0 = D , VPort1 = E , VPort2 = C , VPort3 = R

'Each virtual port is available as PORT0, PORT1, PORT2 and PORT3
' data direct is available as DDR0 , DDR1, DDR2 and DDR3
' PIN input is available as PIN0 , PIN1, PIN2 and PIN3

'The advantage of virtual port registers is that shorter asm instruction can be used which also use only 1 cycle
Dim Var As Byte

'Real Port Direction
Ddr1 = &B0000_0000 ' Port E = INPUT
Ddr0 = &B1111_1111 ' Port D = OUTPUT

'Continously copy the value from PORTE to PORTD using the virtual ports.
Do
Var = Pin1 'Read Virtual Port 0
Port0 = Var 'Write Virtual Port 1
Loop

End 'end program
</source> {{Languages}}

[[Category:BASCOM Language Reference]]

@@ Line 54: / Line 54: @@
 The second config will erase the setting of the first config.
-<span style="font-family: 'Courier New';"></span>[[File:Notice.jpg|notice]]<span style="font-size: 10pt;">Some processors like the ones from the E5 series have a fixed relation. These chips have virtual port registers (port,ddr,pin) and do not need a CONFIG VPORT).For the E5 this relation is :</span>
 PORT0 - Virtual port A
@@ Line 66: / Line 68: @@
 PORT3 - Virtual port R
-<span style="font-family: 'Courier New'; font-size: 10pt;">&nbsp;</span><span style="font-family: 'Courier New';"></span>
+<span style="font-family: 'Courier New'; font-size: 10pt;">&nbsp;</span>
 All ports in the Xmega are located in the extended address area. This space can only be accessed with instructions like LDS,STS, LD and ST.

@@ Line 54: / Line 54: @@
 The second config will erase the setting of the first config.
-<span style="font-family: 'Courier New';">&nbsp;</span>
+<span style="font-family: 'Courier New';"></span>
 All ports in the Xmega are located in the extended address area. This space can only be accessed with instructions like LDS,STS, LD and ST.

@@ Line 41: / Line 41: @@
 </div>
 <span style="font-family: Arial;">&nbsp;</span>
 All ports in the Xmega are located in the extended address area. This space can only be accessed with instructions like LDS,STS, LD and ST.
@@ Line 50: / Line 64: @@
 <span style="font-style: italic;">Xmega example&nbsp;:</span>
-<span style="font-style: italic;">again:</span>
+<span class="f_CodeExample">again</span><span class="f_CodeExample" style="color: rgb(255, 0, 0);">:</span>
-<span style="font-style: italic;">Lds r24, PINA &nbsp;&nbsp;; read port input value</span>
+<span class="f_CodeExample" style="color: rgb(128, 0, 128);">Lds</span><span class="f_CodeExample">&nbsp;r24,&nbsp;PINA &nbsp; &nbsp; &nbsp; &nbsp;</span><span class="f_CodeExample" style="color: rgb(0, 128, 0);">;&nbsp;read&nbsp;port&nbsp;input&nbsp;value</span>
-<span style="font-style: italic;">sbrs r24,7 &nbsp; &nbsp; &nbsp;&nbsp;; skip next instruction if bit 7 is set (1)</span>
+<span class="f_CodeExample" style="color: rgb(128, 0, 128);">sbrs</span><span class="f_CodeExample">&nbsp;r24,7&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span><span class="f_CodeExample" style="color: rgb(0, 128, 0);">;&nbsp;skip&nbsp;next&nbsp;instruction&nbsp;if&nbsp;bit&nbsp;7&nbsp;is&nbsp;set&nbsp;(1)</span>
-<span style="font-style: italic;">rjmp again &nbsp; &nbsp; &nbsp;&nbsp;; try again</span>
+<span class="f_CodeExample" style="color: rgb(128, 0, 128);">rjmp</span><span class="f_CodeExample">&nbsp;again&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span><span class="f_CodeExample" style="color: rgb(0, 128, 0);">;&nbsp;try&nbsp;again</span>
 <span style="font-style: italic;">&nbsp;</span>
@@ Line 62: / Line 76: @@
 <span style="font-style: italic;">Now the same code for a normal AVR</span>
-<span style="font-style: italic;">again:</span>
+<span class="f_CodeExample">again</span><span class="f_CodeExample" style="color: rgb(255, 0, 0);">:</span>
-<span style="font-style: italic;">sbis PINA,7 &nbsp; &nbsp; &nbsp;; skip if pina.7 is set</span>
+<span class="f_CodeExample" style="color: rgb(128, 0, 128);">sbis</span><span class="f_CodeExample">&nbsp;PINA,7&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span><span class="f_CodeExample" style="color: rgb(0, 128, 0);">;&nbsp;skip&nbsp;if&nbsp;pina.7&nbsp;is&nbsp;set</span><span class="f_CodeExample">&nbsp;</span>
-<span style="font-style: italic;">rjmp again</span>
+<span class="f_CodeExample" style="color: rgb(128, 0, 128);">rjmp</span><span class="f_CodeExample">&nbsp;again</span>
 <span style="font-style: italic;">&nbsp;</span>
@@ Line 83: / Line 97: @@
 Devices like graphical LCD can benefit from this.
 <span style="font-family: Arial;">&nbsp;</span>