DSP56857 datasheet(357/662 Pages) FREESCALE

357 / 662 page

Enhanced Synchronous Serial Interface (ESSI), Rev. 4

Freescale Semiconductor

12-57

12.8.14 Transmit Slot Mask Registers (TSMA, TSMB)

The Transmit Slot Mask Registers are two 16-bit read/write registers. In the Network mode, these

registers are used by the transmitter to determine which action to take in the current transmission

slot. Depending on the setting of the bits, the transmitter either tri-states the transmitter data

signal or transmits a data word and generates the appropriate transmit status. TSMA and TSMB

can be viewed as a single 32-bit register named TSM. Bit n in TSM (TSMn) is an enable/disable

control bit for transmission in slot N.

Figure 12-29. Transmit Slot Mask Register (TSMA)

See Programmer’s Sheet on Appendix page B - 82

Figure 12-30. Transmit Slot Mask Register (TSMB)

See Programmer’s Sheet on Appendix page B - 82

•

0 = The transmit data signal of the transmitter is tri-stated during transmit time slot N.

Data is not transferred to the TXSR, therefore transmit status flags are not changed.

Table 12-24.

Status of Transmit FIFO Empty Flag

Transmit FIFO Watermark

(TFWM)

Number of Data in TXFIFO

012345678

111111111

111111100

111111000

111110000

111100000

111000000

110000000

100000000

Base + $C

Read

TSMA [15:0]

Write

Reset

Base + $D

Read

TSMB [31:16]

Write

Reset

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