PXD20RM Datasheet, PDF (989/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

Table 27-18. UARTCR field descriptions
Field
Description
TDFLTFC
Transmitter data field length / Tx FIFO counter
This field has one of two functions depending on the mode of operation as follows:
• When LINFlexD is in UART buffer mode (TFBM = 0), TDFLTFC defines the number of bytes to be
transmitted. The field is read/write in this configuration. The first bit is reserved and not
implemented.
The permissible values are as follows (with X representing the unimplemented first bit):
0bX00: 1 byte
0bX01: 2 bytes
0bX10: 3 bytes
0bX11: 4 bytes
When the UART data length is configured as half-word (WL = 0b10 or 0b11), the only valid values
for TDFLTFC are 0b001 and 0b011.
• When LINFlexD is in UART FIFO mode (TFBM = 1), TDFLTFC contains the number of entries
(bytes) of the Tx FIFO. The field is read-only in this configuration.
The permissible values are as follows:
0b000: Empty
0b001: 1 byte
0b010: 2 bytes
0b011: 3 bytes
0b100: 4 bytes
All other values are reserved.
This field is meaningful and can be programmed only when the UART bit is set.
RDFLRFC
Receiver data field length / Rx FIFO counter
This field has one of two functions depending on the mode of operation as follows:
• When LINFlexD is in UART buffer mode (RFBM = 0), RDFLRFC defines the number of bytes to be
received. The field is read/write in this configuration. The first bit is reserved and not implemented.
The permissible values are as follows (with X representing the unimplemented first bit):
0bX00: 1 byte
0bX01: 2 bytes
0bX10: 3 bytes
0bX11: 4 bytes
When the UART data length is configured as half-word (WL = 0b10 or 0b11), the only valid values
for RDFLRFC are 0b001 and 0b011.
• When LINFlexD is in UART FIFO mode (RFBM = 1), RDFLRFC contains the number of entries
(bytes) of the Rx FIFO. The field is read-only in this configuration.
The permissible values are as follows:
0b000: Empty
0b001: 1 byte
0b010: 2 bytes
0b011: 3 bytes
0b100: 4 bytes
All other values are reserved.
This field is meaningful and can be programmed only when the UART bit is set.
RFBM
Rx FIFO/buffer mode
0 Rx buffer mode enabled
1 Rx FIFO mode enabled (mandatory in DMA Rx mode)
This field can be programmed in initialization mode only when the UART bit is set.
Freescale Semiconductor
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
27-33