Sundance Spas ST201 - Manual (Page 80)

80
Sundance Technology ST201 PRELIMINARY draft 2
TXDMAPOLLPERIOD
Class....................I/O Registers, DMA
Base Address ......IoBaseAddress register value
Address Offset .....0x0a
Access Mode .......Read/Write
Width ...................8 bits
The value in TxDMAPollPeriod determines the interval at which the current TFD is polled. When a zero
TxDMANextPtr is fetched from the current TFD, TxDMANextPtr is polled to determine when a new TFD is
ready to be processed. Polling is disabled when TxDMAPollPeriod is cleared. TxDMAPollPeriod is cleared
by reset. The value in TxDMAPollPeriod represents a multiple of 320 ns time intervals. The maximum
value is 127 (or 40.64 us).
BIT BIT NAME BIT DESCRIPTION
6..0 TxDMAPollPeriod The number of 320ns intervals between polls of the TxDMANextPtr
field of the current TFD.
7 Unused This bit is ignored.