CONFIG EVENT_SYSTEM

CONFIG EVENT_SYSTEM

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Action

This statement configures the Xmega event routing.

 

 

Syntax

CONFIG EVENT_SYSTEM = dummy, MUXx=MUX, QDx=QD, QDIx=QDI, QDIRMx=QDIRM,DIGFLTx=DIGFLT

The letter X is used to indicate that a value between 0 and 7 can be used. So there is MUX0, MUX1, MUX2,MUX3 etc.

 

 

Remarks

The Event System is a set of features for inter peripheral communication. It enables the possibility

for a change of state in one peripheral to automatically trigger actions in other peripherals.

The change of state in a peripheral that will trigger actions in other peripherals is configurable in

software. It is a simple, but powerful system as it allows for autonomous control of peripherals

without any use of interrupt, CPU or DMA resources.

 

There are 8 multiplexers and 8 control registers. Register 0, 2 and 4 can be used for quadrature decoding.

 

 

MUX

There are 8 multiplexers, named MUX0-MUX7. The MUX is used to select an event source.There are many sources for events :

NONE : disabled, default

RTC_OVF : Real Timer overflow

RTC_CMP : Real Timer compare match

ACA_CH0 : analog comparator ACA, channel 0

ACA_CH1 : analog comparator ACA, channel 1

ACA_WIN : analog comparator ACA, window

ACB_CH0 : analog comparator ACB, channel 0

ACB_CH1 : analog comparator ACB, channel 1

ACB_WIN : analog comparator ACB, window

ADCA_CH0- ADCA_CH3 : ADCA channel 0-3

ADCB_CH0- ADCB_CH3 : ADCB channel 0-3

PORTA.0 - PORTA.7 : PORT A pin 0-7

PORTB.0 - PORTB.7 : PORT B pin 0-7

PORTC.0 - PORTC.7 : PORT C pin 0-7

PORTD.0 - PORTD.7 : PORT D pin 0-7

PORTE.0 - PORTE.7 : PORT E pin 0-7

PORTF.0 - PORTF.7 : PORT F pin 0-7

PRESCALER1, PRESCALER2, PRESCALER4, PRESCALER8, PRESCALER16, PRESCALER32, PRESCALER64,PRESCALER128,PRESCALER256,PRESCALER512,PRESCALER1024,PRESCALER2048,PRESCALER4096,PRESCALER8192,PRESCALER16384 : The clock divided by 1,2,4,8,16,32,64,128,256 etc.

 

TCC0_OVF  : Timer TC0 overflow

TCC0_ERR : Timer TC0 error

TCC0_CCA : Timer TC0 capture or compare match A

TCC0_CCB : Timer TC0 capture or compare match B

TCC0_CCC : Timer TC0 capture or compare match C

TCC0_CCD : Timer TC0 capture or compare match D

TCC1_OVF  : Timer TC1 overflow

TCC1_ERR : Timer TC1 error

TCC1_CCA : Timer TC1 capture or compare match A

TCC1_CCB : Timer TC1 capture or compare match B

TCC1_CCC : Timer TC1 capture or compare match C

TCC1_CCD : Timer TC1 capture or compare match D

 

Dito for TCD0, TCD1, TCE0, TCE1, TCF0 and TCF1

 

QD

Enables or disables the quadrature decoder. Will only work on QD0,QD2 and QD4.

QDI

Enables or disables the quadrature decode index. Will only work on QDI0, QDI2 and QDI4.

QDIRM

Quadrature decode index recognition mode. This is a numeric constant between 0 and 3. Each value represents the 2 possible bit values for the two input signals. Will only work on QDIRM0, QDIRM2 and QDIRM4.

DIGFLT

Defines the length of digital filtering used. Events will be passed through to the event channel only when the event source has been active and sampled with the same level for a number of peripheral clock for the number of cycles as defined by DIGFLT.

The number of samples is in the range from 1-8. The default is 1 sample.

 

 

 

 

See also

ATXMEGA

 

 

Example 1:
 
' Select PortC.0 as INPUT to event channel 0
' Digflt0 = 8 --> Enable Digital Filtering for Event Channel 0.

' The Event must be active for 8 samples in order to be passed to the Event system
' Event Channel 1 INPUT = Timer/Counter C0 Overflow
' Event Channel 2 INPUT = Analog Input Port A Channel 0
' Event Channel 3 INPUT = Real Timer overflow
Config Event_system = Dummy , _
Mux0 = Portc.0 , Digflt0 = 8 , _
Mux1 = Tcc0_ovf , _
Mux2 = Adca_ch0 , _
Mux3 = Rtc_ovf

 

 

Example 2:

'Event Channel 7 is input for the Timer/Counter TcD1 overflow

Config Event_system = Dummy , Mux7 = Tcd1_ovf              

 

Example 3:

 
' Using the Counter/Timer to count events like a falling edge on Pine.5
 
$regfile = "xm256a3bdef.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 Com7 = 57600 , Mode = Asynchroneous , Parity = None , Stopbits = 1 , Databits = 8       'Portf.2 and Portf.3 is COM7
Open "COM7:" For Binary As #1
 
'Config Interrupts
Config Priority = Static , Vector = Application , Lo = Enabled , Med = Enabled       'Enable Lo Level Interrupts
 
Dim Timer_overflow As Bit
 
Print #1 , "---Event Counting with Timer C0 over Event Channel 0 from PINE.5----"
 
Config Porte.5 = Input
Config Xpin = Porte.5 , Outpull = Pullup , Sense = Falling 'enable Pullup and reaction on falling edge
Config Event_system = Dummy , Mux0 = Porte.5 , Digflt0 = 8 'Eventchannel 0 =  PINE.5, enable digital filtering

Config Tcc0 = Normal , Prescale = E0 , Event_source = E0 , Event_action = Capture' Normal = no waveform generation, Event Source = Event Channel 0
 
On Tcc0_ovf Timerd0_int
Enable Tcc0_ovf , Lo                                       'Enable overflow interrupt in LOW Priority
Tcc0_per = 5                                               'Interrupt when Count > 5
Enable Interrupts
 
'################MAINLOOP#######################################################
Do
 
Wait 1
Print #1 , "TCC0_CNT = " ; Tcc0_cnt                       'Actual Count
 
If Timer_overflow = 1 Then
  Reset Timer_overflow
  Print #1 , "TCC0_OVERVLOW"                             'Print it when Overflow Interrupt is fired
End If
 
Loop
'################MAINLOOP#######################################################
 
 
End
 
Timerd0_int:
Set Timer_overflow
Return