Specifications

Request Meaning
ALT_DMA_RX_ONLY_OFF Return to the default mode, in which both the receive and transmit
sides of the DMA can be under software control.
Related Information
DMA Controller Core
For more information, refer to the "DMA Controller Core" section of the Embedded Peripherals IP User
Guide.
alt_dma_txchan_space()
Prototype
int alt_dma_txchan_space (alt_dma_txchan dma)
Commonly Called By
C/C++ programs
Device drivers
Thread-safe
See description.
Available from ISR
See description/
Include
<sys/alt_dma.h>
Description
The alt_dma_txchan_space() function returns the number of transmit requests that can be posted to
the specified DMA transmit channel, dma. A negative value indicates that the value cannot be determined.
Whether this function is thread-safe, or can be called from an ISR, depends on the underlying device
driver. In general it safest to assume that it is not thread-safe.
Return
Returns the number of transmit requests that can be posted.
Related Information
• alt_dma_rxchan_close() on page 14-13
• alt_dma_rxchan_depth() on page 14-12
• alt_dma_rxchan_open() on page 14-15
• alt_dma_rxchan_prepare() on page 14-16
• alt_dma_rxchan_reg() on page 14-17
• alt_dma_txchan_close() on page 14-18
14-26
alt_dma_txchan_space()
NII5V2
2015.05.14
Altera Corporation
HAL API Reference
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