Information

Push TX FIFO Register
Transmit Next
Data Pointer
Shift Register
SOUT
+1
-1
TX FIFO Counter
TX FIFO Base
-
Entry C
Entry A (first in)
Entry D (last in)
Entry B
-
-
-
Figure 46-78. TX FIFO Pointers and Counter
46.5.5.1 Address Calculation for the First-in Entry and Last-in Entry
in the TX FIFO
The memory address of the first-in entry in the TX FIFO is computed by the following
equation:
The memory address of the last-in entry in the TX FIFO is computed by the following
equation:
TX FIFO Base - Base address of TX FIFO
TXCTR - TX FIFO Counter
TXNXTPTR - Transmit Next Pointer
TX FIFO Depth - Transmit FIFO depth, implementation specific
46.5.5.2 Address Calculation for the First-in Entry and Last-in Entry
in the RX FIFO
The memory address of the first-in entry in the RX FIFO is computed by the following
equation:
Initialization/Application Information
K20 Sub-Family Reference Manual, Rev. 6, Nov 2011
1254 Freescale Semiconductor, Inc.