mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 1095

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

43.3.30 UART 7816 Transmit Length Register (UARTx_TL7816)
The TL7816 register is used to indicate how many characters are contained in the block
being transmitted. This register is only used when C7816[TTYPE] = 1. This register may
be read at anytime. This register should only be written when C2[TE] is not enabled.
Addresses: UART0_TL7816 is FFFF_8140h base + 1Fh offset = FFFF_815Fh
43.4 Functional description
This section provides a complete functional description of the UART block.
The UART allows full duplex, asynchronous, NRZ serial communication between the
CPU and remote devices, including other CPUs. The UART transmitter and receiver
operate independently, although they use the same baud rate generator. The CPU
monitors the status of the UART, writes the data to be transmitted, and processes
received data.
Freescale Semiconductor, Inc.
TLEN
Reset
Field
Read
7–0
Write
Bit
UART1_TL7816 is FFFF_8160h base + 1Fh offset = FFFF_817Fh
Transmit Length
This value plus 4 indicates the number of characters contained in the block being transmitted. This
register is automatically decremented by 1 for each character in the information field portion of the block.
Additionally, this register is automatically decremented by 1 for the first character of a CRC in the epilogue
field. Hence, this register should be programmed with the number of bytes in the data packet if a LRC is
being transmitted, and the number of bytes + 1 if a CRC is being transmitted. This register is not
decremented for characters that are assumed to be part of the Prologue field (first three characters
transmitted in a block) or the LRC or last CRC character in the Epilogue field (last character transmitted).
This field should only be programed or adjusted when C2[TE] is cleared.
7
0
0
6
MCF51JF128 Reference Manual, Rev. 2, 03/2011
UARTx_TL7816 field descriptions
0
5
Chapter 43 Universal Asynchronous Receiver/Transmitter (UART)
Preliminary
0
4
Description
TLEN
0
3
0
2
0
1
0
0
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