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This version (19 Jun 2017 11:10) was approved by CsomI.

Channel CPACK Utility Core (util_cpack)

The channel CPACK utility core is meant to allow one or more channels to be enabled by software without any padding. This allows full usage of the DMA bandwidth without any overhead. This core is normally works with an ADC and DMA modules. The ADC interface is channel based (one interface per each ADC channel) and consists of enable, valid and data signals. The DMA interface is a single FIFO interface consisting of valid and data signals. The enable signals are usually controlled by software. The core simply packs the ADC data of the individual channels into a single data bus, as defined by the ADC enables.

Features

  • Supports Intel/Altera and Xilinx devices
  • Supports up to 8 channels
  • Supports configurable channel data width

Functional Description

The core 'collects' samples from the ADC interface and passes it to the DMA (or any other sink module), the data flow is controlled by the ADC. This is best explained through some examples. Let's consider a 4 channel ADC with a channel data width of 32 bits. The ADC core provides two 16-bit samples on its output for all channels when the valid is asserted. The DMA interface, in this case, is an interleaved 8 samples (128 bits) stream. This is because irrespective of the ADC channel data width, the software always sees data as 'samples interleaved'. The same data set may received by the DMA core with a channel width of 128 bits or 16 bits.

a. Four channels enabled (4'b1111)

b. Three channels enabled (4'b1110)

c. Two channels enabled (4'b1100)

Parameters

Name Description Default Value
CHANNEL_DATA_WIDTH Data width of a channel 32
NUM_OF_CHANNELS Number of channels, max value is 8 8

Interface

Interface/Pin Type Description
adc_clk input ADC interface clock (core clock). The module runs on this clock.
adc_rst input Reset signal from the ADC core.
FIFO interfaces from the ADC core
adc_enable_* input Indicates the status of the channel, if asserted the channel is active
adc_valid_* input Indicates a valid data on the adc_data_* bus
adc_data_* input[(CHANNEL_DATA_WIDTH-1):0] ADC data bus from the ADC core
FIFO interface to the DMA (sink)
adc_valid output Indicates data on the adc_data bus
adc_sync output Control the correct alignment, when the source and sink interface data width is different. When this bit is asserted, the first sample on the DMA interface (16 bit LBS), must be a sample of the first channel.
adc_data output[(CHANNEL_DATA_WIDTH-1):0] DAC data bus to the DAC core (sink)

Register Map

This core does not have a register map.

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resources/fpga/docs/util_cpack.txt · Last modified: 19 Jun 2017 11:10 by CsomI