Uart 7816 Transmit Length Register (Uartx_Tl7816); Uart 7816 Atr Duration Timer Register A (Uartx_Ap7816A_T0) - NXP Semiconductors MKL27Z128VFM4 Reference Manual

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RXTHRESHOLD Receive NACK Threshold

The value written to this field indicates the maximum number of consecutive NACKs generated as a result

of a parity error or receiver buffer overruns before the host processor is notified. After the counter exceeds

that value in the field, the IS7816[RXT] is asserted. This field is meaningful only when C7816[TTYPE] = 0.

The value read from this field represents the number of consecutive NACKs that have been transmitted

since the last successful reception. This counter saturates at 4'hF and does not wrap around. Regardless

of the number of NACKs sent, the UART continues to receive valid packets indefinitely. For additional

information, see IS7816[RXT] field description.

38.4.20 UART 7816 Transmit Length Register (UARTx_TL7816)

The TL7816 register is used to indicate the number of characters contained in the block

being transmitted. This register is used only when C7816[TTYPE] = 1. This register may

be read at anytime. This register must be written only when C2[TE] is not enabled.

Address: 4006_C000h base + 1Fh offset = 4006_C01Fh

Transmit Length

This value plus four indicates the number of characters contained in the block being transmitted. This

Additionally, this register is automatically decremented by 1 for the first character of a CRC in the epilogue

field. Therefore, this register must be programmed with the number of bytes in the data packet if an 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, that is, the first three

characters transmitted in a block, or the LRC or last CRC character in the Epilogue field, that is, the last

character transmitted. This field must be programed or adjusted only when C2[TE] is cleared.

38.4.21 UART 7816 ATR Duration Timer Register A

(UARTx_AP7816A_T0)

The AP7816A_T0 register contains variables used in the generation of the ATR Duration

Timer. This register may be read at any time. This register must be written to only when

C7816[ISO_7816E] is not set, except when writing 0 to clear the ADT Counter.

Freescale Semiconductor, Inc.

Chapter 38 Universal Asynchronous Receiver/Transmitter(UART)

UARTx_ET7816 field descriptions (continued)

UARTx_TL7816 field descriptions

KL27 Sub-Family Reference Manual , Rev. 5, 01/2016