FILE: sdfm_ex6_FIFO_freeze_claread.c
In this example, SDFM FIFO will not be filled until a SDSYNC event. On a SDSYNC event, SDFM data filter output will start filling FIFO and stop filling after programmable number 'N' of FIFO is filled.
SDy-C1 (Filter1 channel clock) is internally configured to connected SDy-C2 / SDy-C3 / SDy-C4 SDFM configuration is shown below:
- SDFM1 used in this example.For using SDFM2, few modifications would be needed in the example.
- MODE0 Input control mode selected
- Comparator settings
- Sinc3 filter selected
- OSR = 32
- hlt = 0x7FFF (Higher threshold setting)
- llt = 0x0000(Lower threshold setting)
- Data filter settings
- All the 4 filter modules enabled
- Sinc3 filter selected
- OSR = 256
- All the 4 filters are synchronized by using MFE (Master Filter enable bit)
- Filter output represented in 16 bit format
- In order to convert 25 bit Data filter into 16 bit format user needs to right shift by 10 bits for Sinc3 filter with OSR = 256
- Interrupt module settings for SDFM filter
- All the 4 higher threshold comparator interrupts disabled
- All the 4 lower threshold comparator interrupts disabled
- All the 4 modulator failure interrupts disabled
- All the 4 filter will generate interrupt when a new filter data is available
External Connections
- SDFM_PIN_MUX_OPTION1 Connect Sigma-Delta streams to (SDx-D1, SDx-C1 to SDx-D4,SDx-C4) on GPIO16-GPIO31
- SDFM_PIN_MUX_OPTION2 Connect Sigma-Delta streams to (SDx-D1, SDx-C1 to SDx-D4,SDx-C4) on GPIO46-GPIO61
Watch Variables
- filter1Result - Output of filter 1
- filter2Result - Output of filter 2
- filter3Result - Output of filter 3
- filter4Result - Output of filter 4