573b1d415c
This change adds the following improvements:
- Increase the allowed SPI-Frequency from 20 to 40 MHz.
- Correct and rename the "VARSELECT" option This option was included in the code as "CONFIG_SPI_VARSELECT" but nowhere defined in a Kconfig file. The patch renames it to "CONFIG_SAMV7_SPI_VARSELECT" and corrects the implementation according the datasheet of Atmel. In short, this option switches the processor from "fixed peripheral selection" (single device) to "variable peripheral selection" (multiple devices on the bus).
- Add a new Function to the interface to control the timing and delays of the chip according the ChipSelect lines. This function can control the delay between the assertion of the ChipSelect and the first bit, between the last bit and the de-assertion of the ChipSelect and between two ChipSelects. This is needed to tune the transfer according the specification of the connected devices.
- Add three "hw-features" for the SAMV7, which controls the behavior of the ChipSelect:
1. force CS inactive after transfer: this forces a (short) de-assertion of the CS after a transfer, even if more data is
available in time
2. force CS active after transfer: this forces the CS to stay active after a transfer, even if the chip runs out of data. Btw.: this is a prerequisit to make the LASTXFER bit working at all.
- escape LASTXFER: this suppresses the LASTXFER bit at the end of the next transfer. The "escape"-Flag is reset automatically.
104 lines
2.6 KiB
Plaintext
104 lines
2.6 KiB
Plaintext
#
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# For a description of the syntax of this configuration file,
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# see the file kconfig-language.txt in the NuttX tools repository.
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#
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if SPI
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config SPI_SLAVE
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bool "SPI slave"
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default n
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---help---
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Enable support for SPI slave features
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if SPI_SLAVE
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config SPI_SLAVE_DMA
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bool "SPI slave DMA"
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default n
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depends on ARCH_DMA && EXPERIMENTAL
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---help---
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Enable support for DMA data transfers (not yet implemented).
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endif
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config SPI_EXCHANGE
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bool "SPI exchange"
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default y
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---help---
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Driver supports a single exchange method (vs a recvblock() and
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sndblock() methods).
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config SPI_CMDDATA
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bool "SPI CMD/DATA"
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default n
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---help---
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Devices on the SPI bus require out-of-band support to distinguish
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command transfers from data transfers. Such devices will often support
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either 9-bit SPI (yech) or 8-bit SPI and a GPIO output that selects
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between command and data.
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config SPI_CALLBACK
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bool "Media change callbacks"
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default y if MMCSD_SPI
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default n if !MMCSD_SPI
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---help---
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Support the callback method in the SPI interface. This will allow
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the SPI-based MMC/SD driver to get a notification of changes in the
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card status when an SD card is inserted or removed.
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config SPI_BITBANG
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bool "SPI bit-bang device"
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default n
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---help---
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Enable support for a generic SPI bit-bang device.
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See include/nuttx/spi/spi_bitbang.h for further information.
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config SPI_HWFEATURES
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bool
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default n
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---help---
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Selected only if a specific H/W feature is selected. This is
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basically the OR of any specific hardware feature and eanbles
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the SPI hwfeatures() interface method.
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config SPI_CRCGENERATION
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bool
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default n
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select SPI_HWFEATURES
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---help---
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Selected by MCU Kconfig logic if implementation supports automatic
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generation of SPI CRCs. Enables the HWFEAT_CRCGENERATION option
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as well as the hwfeartures() interface method.
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config SPI_CS_CONTROL
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bool "SPI CS Behavior Control"
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default n
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select SPI_HWFEATURES
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---help---
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Enables possibilities to define the behavior of CS.
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Also enables the hwfeatures() interface method.
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config SPI_CS_DELAY_CONTROL
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bool "SPI CS Delay Control"
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default n
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---help---
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Enables possibilities to define the SPI-ChipSelect-Delays like
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time between ChipSelect assertion and first Data-Bit, the time
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between the last Data-Bit and the de-assertion and the minimum
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delay between two ChipSelects.
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This option enables the setdelay() interface method.
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if SPI_BITBANG
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config SPI_BITBANG_VARWIDTH
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bool "SPI bit-bang variable width transfers"
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default n
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---help---
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Enable support for a variable data width transfers. Default: 8-bit
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only.
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endif # SPI_BITBANG
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endif # SPI
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