Sundance-spas ST201 Manual de usuario descargar pdf (Pagina 62)

Sundance Technology ST201 PRELIMINARY draft 2

TXSTARTTHRESH

Class....................I/O Registers, FIFO Control

Base Address ......IoBaseAddress register value

Address Offset.....0x3c

Access Mode.......Read/Write

Width ...................16 bits

The value in TxStartThresh is used to control when frames are transmitted. Transmission of a frame

begins when the number of bytes for the frame transferred into the TxFIFO is greater than the value in

TxStartThresh. If TxStartThresh is set too low, the TxFIFO may experience under run due to the DMA data

transfers not able to keep up with the wire data rate. Host systems should use under run indications as a

hint to increase the TxStartThresh value. This register resets to 1ffch, which disables the threshold mecha-

nism.

BIT BIT NAME BIT DESCRIPTION

12..0 TxStartThresh The number of bytes which must be present in the TxFIFO before

frame transmission begins. Values will be interpreted using a resolu-

tion of 4 bytes (i.e. 0x00, 0x04, 0x08, 0x0c, 0x0f, etc.)

15..13 Unused These bits are ignored.

1 2 ... 57 58 59 60 61 62 63 64 65 66 67 ... 144 145

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Sundance-spas ST201 Manual de usuario Pagina 62