motor-control-sdk/docs_src/docs/api_guide/examples/sdfm_example.md

%SDFM

[TOC]

The ICSS %SDFM driver provides a well defined set of APIs to expose sigma delta interface.

The ICSS %SDFM example invokes these APIs to

• Set %SDFM channels
• Set ACC source, NC OSR, OC OSR, Clock source & Clock inversion
• Enable & disable threshold comparators
• Set high and low threshold values
• configure normal current sample trigger time (time for read sample)
• Enable & disable double update
• Inform firmware to enable %SDFM mode
• Configure GPIO pins for high and low threshold
• Configure fast detect block

Once these steps are executed

• ICSS %SDFM example waits for a interrupt (trigger by %SDFM firmware) to read sample data
• when interrupt occurs, example reads sample data from DMEM and again comes back to waiting loop

ICSS SDFM Example Implementation

Following section describes the Example implementation of ICSS %SDFM on ARM(R5F). \image html SDFM_EXAMPLE_FLOWCHART.png "ICSS SDFM Example"

Important files and directory structure

Folder/Files	Description
${SDK_INSTALL_PATH}/examples/current_sense/icss_sdfm
app_sdfm.c & sdfm.c	ICSS %SDFM application
${SDK_INSTALL_PATH}/source/current_sense/sdfm
firmware/	Folder containing %SDFM firmware sources
driver/	ICSS %SDFM driver
include/	Folder containing ICSS %SDFM structures & APIs sources

Supported Combinations

\cond SOC_AM64X

Parameter	Value
CPU + OS	r5fss0-0 freertos
ICSSG	ICSSG0
PRU	PRU0
Toolchain	ti-arm-clang
Board	@VAR_BOARD_NAME_LOWER
Example folder	examples/current_sense/icss_sdfm

\endcond

\cond SOC_AM243X

Parameter	Value
CPU + OS	r5fss0-0 freertos
ICSSG	ICSSG0
PRU	PRU0
Toolchain	ti-arm-clang
Board	@VAR_BOARD_NAME_LOWER, @VAR_LP_BOARD_NAME_LOWER
Example folder	examples/current_sense/icss_sdfm

\endcond

Steps to Run the Example

Hardware Prerequisites

Other than the basic EVM setup mentioned in EVM Setup , below additional HW is required to run this demo

• TIDEP-01015 3 Axis board
• Interface card connecting EVM and TIDEP-01015 3 Axis board
• Signal generator

Hardware Setup

\image html SDFM_HwSetup_image.PNG "Hardware Setup SDFM" \image html SDFM_EVM_HW_setup.png "SDFM: EVM and 3axis board setup view" \cond SOC_AM243X

Hardware Prerequisities for LP

• AMC1035EVM
• AM243x-LP board
• Signal generator

LP Hardware set up

\image html SDFM_LpHwSetup_image.png "LP Hardware setup" \image html SDFM_LpHwSetup.png "SDFM: LP setup view" \endcond

Build, load and run

• When using CCS projects to build, import the CCS project and build it using the CCS project menu (see Using SDK with CCS Projects ).
• When using makefiles to build, note the required combination and build using make command (see Using SDK with Makefiles )
• Launch a CCS debug session and run the executable, see CCS Launch, Load and Run
• Refer to UART terminal for user interface menu options.

Test Case Description

\cond SOC_AM243X \endcond

Test detail	Steps	Pass/fail crieteria
1. Normal current sample data	1. Run icss sdfm example on am64x/am243x board	he drawn graph and raw data should look like the attached image
	2. Draw the graph of sdfm_ch0_samples, sdfm_ch1_samples and sdfm_ch2_samples arrays	\image html SDFM_sample_output.PNG "NC sample data"
2. To check raw data for Single Update (64 NC OSR)	1. Set NC OSR to 64	The drawn graph and raw data should look like the attached image
	2. Set single update trigger time to half of epwm cycle time
	3. Disable double update
	3. Build and run icss sdfm example
	4. Draw graph for Raw data	\image html SDFM_Single_update_64OSR.PNG "Single Update Raw data"
3. To check Raw data for Double Update	1. Set NC OSR to 64	drawn Graphs and raw data should look like attached image
	2. Enable double update
	3. Set single update trigger time to 1/4 of epwm cycle time
	4. Set double update trigger time to 3/4 of epwm cycle time
	5. Build and run icss sdfm example
	6. Draw graph for Raw data	\image html SDFM_Double_update_64OSR.PNG "Double Update Raw data"
		The pattern of the graph should be different from the single update graph. It takes 2 samples in one EPWM cycle so the graph pattern should look more like a sine wave compare to single update graph
4. To check Threshold comparator and Over current	1. Set High Threshold to 3500 and low threshold to 2500	Logic analyzer capture for High & Low Thresholds
	2. Set Over current OSR to 32	\image html SDFM_threshold_comparator_salea_capture.png "Logic analyzer Capture"
	3. Probe Ch0 high, low threshold GPIO pins & input signal
	4. Build and run icss sdfm example
	5. Capture signal in Logic analyzer
5. To check NC Samples with Different NC OSR Values	1. Set NC OSR values between 16 to 255	Raw data should have different resolution for different OSR values
	2. Build and run icss sdfm example
	3. Observe resolution of raw data
6. To check NC samples with different sdfm clock values	1. Set NC OSR to 64	Raw data should have different resolution for different sdfm clock values
	2. Set ecap_divider variable in sdfm.c file for different sd clock generation
	3. Set Sigma delta clock equal to ecap generated clock
	4. Build and run example
	5. Observe resolution of raw data
7. To check Fast detect	1. Set NC OSR to 64	Trip must be triggered for the respective pwm trip zone block
	2. Enable Fast detect
	3. Set Fast Detect fields with these values { window size = 4, Zero max = 18, Zero min = 2}	Zero max/min Threshold hit bits must be constantly unset and set
	4. Build and run example	One max/min threshold hit bits must be unset
	5. 1) Observe TZ_OUT PIN. 2) Check zero/one count max & zero/one count min threshold hit bits in memory map
8.Testing with sdfm clock from EPWM	1. Make hardware set up like attached image	All test cases results should match with ECAP test case results
	2. \image html SDFM_EPWM1_HW_Setup.png "SDFM: Hw set for clock from EPWM"
	3. Enable "APP_EPWM1_ENABLE" macro in app_sdfm.c file
	4. Set EPWM1 out put frequency to 12.5MHz or 5MHz in app_sdfm.c file
	5. Set Sigma delta clock equal to EPWM1 output frequency
	6. Build and run icss sdfm example
	7. Test all tese cases from 1 to 5 with EPWM clock