Sundance Spas ST201 - Manual (Page 72)

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Sundance Technology ST201 PRELIMINARY draft 2
RXDMABURSTTHRESH
Class....................I/O Registers, DMA
Base Address ......IoBaseAddress register value
Address Offset .....0x14
Access Mode .......Read/Write
Width ...................8 bits
RxDMABurstThresh sets the threshold when the ST201 makes RxDMA bus master requests, based upon
the number of used bytes in the RxFIFO, in units of 32 bytes. When the used space exceeds the threshold,
the ST201 may make a RxDMA request on the PCI bus. However, if the used space exceeds the current
RxDMAFragLen, ST201 will make RxDMA bus request regardless of whether the used space exceeds the
RxDMABurstThresh or not. RxDMABurstThresh may be overridden by the urgent request mechanism.
See the PCI Bus Master Operation section for information about the relationship between RxDMABurst-
Thresh and RxDMAUrgentThresh. A value of zero is invalid. RxDMABurstThresh defaults to 8, a threshold
of 256 bytes.
BIT BIT NAME BIT DESCRIPTION
7..0 RxDMABurst-
Thresh The number of 32 byte words which must be present in the RxFIFO
prior to the assertion of a RxDMA bus master request.