Mux Axi / ISR Trigger Control

  • Selects the PWM counter event that triggers ADC and the interrupt of the R5 processor

  • Selects ADC/ISR trigger ratio: trigger the ISR in the R5 every n-th ADC trigger event (n = 1,2,3,...)

PWM counter events

  • The PWM and SS Control as well as the 3-level PWM ip core use an up-down counter

  • At counter min and max those ip cores provide rising edge signals that are fed to the uz_mux_axi ip core

  • Those trigger signals depend on the selected PWM frequency

Interrupt sources

  • The user selects the trigger source for ADC triggering via the #define INTERRUPT_ISR_SOURCE_USER_CHOICE in uz_global_configuration.h (see Global configuration)

  • The selected trigger source also triggers the ISR in the R5 processor (see also Interrupts R5)

  • Below, as well as in uz_global_configuration.h, the user will find the valid interrupt source options:

/** ISR trigger source
 *
 * chose here which of the above interrupt trigger you want to use:
 * 0 for Interrupt_2L_max_min
 * 1 for Interrupt_2L_min
 * 2 for Interrupt_2L_max
 * 3 for Interrupt_3L_start_center
 * 4 for Interrupt_3L_start
 * 5 for Interrupt_3L_center
 * 6 for Interrupt_timer_fcc
*/

ADC/ISR trigger ratio

  • If necessary, the user can choose an integer multiple ratio between ADC and ISR triggering

  • This is done by setting the INTERRUPT_ADC_TO_ISR_RATIO_USER_CHOICE #define in uz_global_configuration.h

Example

The user wants to have a PWM frequency of 100 kHz and an ISR frequency of 20 kHz:

  • The user selects the PWM frequency of 100 kHz: the define UZ_PWM_FREQUENCY is set to 100.0e3f in uz_global_configuration.h

  • The trigger source is Interrupt_2L_min: the define INTERRUPT_ISR_SOURCE_USER_CHOICE is set to 1U in uz_global_configuration.h

  • The trigger ratio is set to 5 (100 kHz/20 kHz = 5): the define INTERRUPT_ADC_TO_ISR_RATIO_USER_CHOICE is set to 5U in uz_global_configuration.h

Listing 161 Settings in uz_global_configuration.h for the example
#define INTERRUPT_ISR_SOURCE_USER_CHOICE        1U
#define INTERRUPT_ADC_TO_ISR_RATIO_USER_CHOICE  5U

#define UZ_D5_INCREMENTAL_ENCODER_RESOLUTION    5000.0f
#define UZ_D5_MOTOR_POLE_PAIR_NUMBER            4.0f
#define UZ_PWM_FREQUENCY                        10.0e3f

These settings result in the behavior depicted in Fig. 115 (ADC interrupt in the upper subplot, interrupt of R5 in the lower subplot):

../../../_images/adc_to_isr_ratio.png

Fig. 115 Resulting trigger ratio from the example above

Warning

  • Trigger ratios other than 1 were only tested with trigger source Interrupt_2L_min

  • Especially when using trigger sources with two ADC trigger events (e.g. Interrupt_2L_max_min), the user has to take care of the resulting ADC/ISR trigger ratio

IP-Core

The IP-Core takes up to 8 different interrupt sources as inputs (external port interrupts_in). One of these inputs is selected by AXI configuration and routed directly routed to the interrupt_out_adc external port. Additionally, all interrupt sources of interrupts_in are coupled with an internal counter that routes the signal of interrupts_in to interrupt_out_isr every n-th time the interrupt_out_adc signal is high. Table Interface of uz_mux_axi IP-Core lists all input and output ports (AXI and external port) that are present in the IP-Core.

Table 15 Interface of uz_mux_axi IP-Core

Port Name

Port Type

Data Type

Target Platform Interfaces

Range

Unit

Function

interrupts_in

Input

uint8

External Signal

interrupt input vector

interrupt_out_adc

Output

bool

External Signal

ADC trigger signal

interrupt_out_isr

Output

bool

External Signal

ISR trigger signal

select_out

Output

ufix4

External Signal

0-6

selected mux number

select_AXI

Input

uint32

AXI4-Lite

0-6

mux selector

select_n_th_adc_interrupt

Input

uint32

AXI4-Lite

1-255

ADC/ISR trigger ratio

Fig. 116 of the IP-Core embedded in the block design:

../../../_images/ipcore.png

Fig. 116 IP-Core in the default Vivado block design.

Software driver

The software driver is initialized by default. The user just has to select the mux and the interrupt ratio #define in uz_global_configuration.h The IP-Core is initialized at the startup of the system. The software driver is not intended to change the settings at runtime.

Reference

typedef struct uz_mux_axi_t uz_mux_axi_t

Data type for object uz_mux_axi.

struct uz_mux_axi_config_t

Configuration struct for uz_mux_axi.

Public Members

uint32_t base_address

Base address of the IP-Core

uint32_t ip_clk_frequency_Hz

Clock frequency of the IP-Core

uint32_t mux

Select value for the mux

uint32_t n_th_interrupt

Trigger ratio of adc_interrupt/isr_interrupt between 1 and 255

uz_mux_axi_t *uz_mux_axi_init(struct uz_mux_axi_config_t config)

Initializes an instance of the uz_mux_axi driver.

Parameters:

  • config – Configuration values for the IP-Core

Returns:

Pointer to initialized instance

void uz_mux_axi_enable(struct uz_mux_axi_t *self)

Enables the instance of the uz_mux_axi IP-Core.

Parameters:

  • self – Pointer to IP-Core instance that was initialized with init function

void uz_mux_axi_set_mux(struct uz_mux_axi_t *self, uint32_t mux)

Sets the mux value (selects the interrupt source)

Parameters:

  • self – Pointer to IP-Core instance that was initialized with init function

  • mux – Value of the selected mux (see uz_global_configuration.h)

void uz_mux_axi_set_n_th_interrupt(struct uz_mux_axi_t *self, uint32_t n_th_interrupt)

Sets the n_th_interrupt value (sets the interrupt ratio between adc_interrupt/isr_interrupt)

Parameters:

  • self – Pointer to IP-Core instance that was initialized with init function

  • n_th_interrupt – Value that sets the ratio between adc_interrupt and isr_interrupt