Infineon CCU6 Interrupt 1 User manual

AURIX™ TC2xx Microcontroller Training
V1.0.0
CCU6_Interrupt_1
CCU6 interrupt generation
Please read the Important Notice and Warnings at the end of this document

Scope of work
The CCU6 unit generates an interrupt every 500 ms and increments a
counter in its Interrupt Service Routine (ISR).
Timer T12 of the CCU6 unit generates an interrupt on a "period match" event
every 500 ms. Inside the ISR, a counter variable is incremented. The LEDs
toggle based on the value of the counter:
›1st LED: counter % 4 == 0
›2nd LED: counter % 4 == 1
›3rd LED: counter % 4 == 2
›4th LED: counter % 4 == 3
2
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.

Introduction
›The Capture/Compare Unit 6 (CCU6) is a high-resolution 16-bit capture
and compare unit with application specific modes, mainly used for AC
drive control.
›The CCU6 unit is made up of a Timer T12 Block with three
capture/compare channels and a Timer T13 Block with one compare
channel. In this example, Timer T12 Block is used.
›Among other features, the CCU6 has the capability to generate
interrupts when its count reaches a predefined period value (16-bit).
3
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.

Hardware setup
This code example has been
developed for the board
KIT_AURIX_TC297_TFT_BC-Step.
4
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.

Implementation
Configure and control the LEDs
The LEDs can be switched on/off by controlling the port pins to which they are connected using methods from
the iLLD headers IfxPort.h.
In the setup phase, the port pins connected to the LEDs are configured as push-pull output mode using the
function IfxPort_setPinMode().
During program execution, the LEDs are switched on and off using the function IfxPort_setPinState().
5
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.

Implementation
Configure the CCU6 unit
Configuration of the CCU6 Timer is done by initializing an instance of the IfxCcu6_Timer_Config structure,
which contains the following fields:
›base –a structure that allows to set:
–frequency –input clock frequency in Hz of the timer module
–period –16-bit register that determines the maximum count value for the timer
›timer –a parameter that allows to choose which of the two timers to configure
›interrupt1 –a structure that allows to set:
–priority –priority of the generated interrupt by CCU6. It can be a value from 0 to 255, with 0 meaning
interrupt is disabled, and 255 is the highest priority
–type of service –defines the service provider responsible for handling the interrupt, which can be any
of the available CPUs, or the DMA
›trigger –a structure for configuring the trigger, that allows to start Timer T13 in sync with Timer T12
The function IfxCcu6_Timer_initModuleConfig() fills the configuration structure with default values and
IfxCcu6_Timer_initModule() function initializes the timer module with the user configuration.
Both functions can be found in the iLLD header IfxCcu6_Timer.h.
6
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.

Implementation
Timer module frequency
In Timer Mode, the input clock of the timer module is derived from the internal module clock fCC6.
By default, the internal module clock fCC6 is initialized by the iLLDs to run at 100 MHz.
The initialization is done by the function IfxScuCcu_init() that can be found in the iLLD header IfxScuCcu.h.
Starting from this value, it is possible to set the timer module frequency to the following exact values:
100000000 Hz = 100 MHz ( fCC6 )
50000000 Hz = 50 MHz ( fCC6 / 2 )
25000000 Hz = 25 MHz ( fCC6 / 4 )
12500000 Hz = 12.5 MHz ( fCC6 / 8 )
6250000 Hz = 6.25 MHz ( fCC6 / 16 )
3125000 Hz ~ 3 MHz ( fCC6 / 32 )
1562500 Hz ~ 1.5 MHz ( fCC6 / 64 )
781250 Hz ~ 780 KHz ( fCC6 / 128 )
390625 Hz ~ 390 KHz ( fCC6 / 256 )
195312.5 Hz ~ 200 KHz ( fCC6 / 512 )
97656.25 Hz ~ 100 KHz ( fCC6 / 1024 )
48828.12 Hz ~ 50 KHz ( fCC6 / 2048 )
24414.06 Hz ~ 25 KHz ( fCC6 / 4096 )
12207.03 Hz ~ 12.5 KHz ( fCC6 / 8192 )
6103.51 Hz ~ 6 KHz ( fCC6 / 16384 )
3051.75 Hz ~ 3 KHz ( fCC6 / 32768 )
Note: Any value can be set as frequency parameter, but the software will round up the chosen value to the
nearest higher frequency listed in the above table (e.g. setting timerConfig.base.t12Frequency = 400000
the timer will run at 781250 Hz).
7
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.

Implementation
ISR Frequency calculation
To calculate the actual ISR frequency fISR (rate at which the ISR is triggered by the CCU6), two parameters
have to be considered: CCU6 clock frequency and period.
›The CCU6 clock frequency can be freely selected as discussed in the previous slide
›The period value is stored in a 16-bit register, which limits its maximum value to 65535.
The ISR frequency can then be calculated as:
fISR = (CCU6 clock frequency) / (period + 1)
8
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.

Implementation
Period calculation example
Target: set a period frequency of fISR = 10 Hz
Considering the maximum value of the period (65535) and the final ISR frequency that needs to be achieved
(10 Hz), the ISR frequency formula from the previous slide leads to the following:
10 Hz = ( CCU6 clock frequency ) / ( period + 1 ) = ( CCU6 clock frequency ) / ( 65535 + 1 )
which leads to: CCU6 clock frequency = ( 65535 + 1 ) * 10 Hz = 655360 Hz
Since the maximum value of 65535 for the period cannot be exceeded, it is needed to search into the previous
table for the nearest lower exact frequency available, which is 390625 Hz.
Taking this value, the period can be easily re-calculated as:
period = ( CCU6 clock frequency / fISR ) –1 = ( 390625 / 10 ) – 1 ≈ 39061
Finally, selecting these values as period and CCU6 clock frequency, fISR can be calculated:
fISR = ( CCU6 clock frequency ) / ( period + 1 ) = 390625 / 39062 ≈ 10 Hz
9
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.

Run and Test
After code compilation and flashing
the device, observe the behavior of
the LEDs.
›Check that LEDs D107, D108,
D109, D110 (1) are blinking
in sequence and changing their
state every 500 ms!
1
10
2019-10-17 Copyright © Infineon Technologies AG 2019. All rights reserved.