NXP Semiconductors PN7462 series User Manual page 218

NXP Semiconductors
Bit Symbol Access
4:0 ftc(4:0) R/W
13.6.2.5 Register ct_gtr1_reg/ct_gtr2_reg (Guard Time Register)
This configuration register is used to store the guard time given by the card during ATR.
This register is doubled: ct_gtr1_reg is dedicated to the full slot and ct_gtr2_reg is
dedicated to the auxiliary slot. Both registers share the same address, the selection is
done via bit IOauxen of register ct_ssr_reg.
Table 253. ct_gtr1_reg/ct_gtr2_reg (address 0010h) bit description
Bit Symbol Access
31:8 RESERVED -
7:0 GT7-GT0 R/W
UM10858
User manual
COMPANY PUBLIC
Reset Description
Value
the card. If not, the firmware has the possibility to pursue the transmission. By
reading the number of bytes present into the FIFO (ffl bits), it can determine
which character has been naked PEC +1 times by the card. It will then flush the
FIFO (FIFO flush bit). The next step consits in unlocking the transmission using
dispe bit. By writing this bit at logic level one (and then at logic level zero if the
firmware still wants to check parity errors), the transmission is unlocked. The
firmware can now write bytes into the FIFO.
•
In transmission mode, if bits PEC(2:0) are at logic 0, then the automatic
retransmission is invalidated. There is no retransmission; the transmission
continues with the next character sent at 13 ETU.
- In protocol T = 1:
The error counter has no action: bit pe is set at logic 1 at the first wrong
received character.
0001b FIFO Threshold Configuration
Define the number of received or transmitted characters in the FIFO triggering
the ft bit in ct_usr1_reg. The FIFO depth is 32 bytes.
In reception mode, it enables to know that a number equals to ftc(4:0) + 1 bytes
have been received. In transmission mode, ftc(4:0) equals to the number of
remaining bytes into the FIFO.
Be careful: in reception mode 00000 = length 1, and in transmission mode
00000 = length 0.
Reset Description
Value
0 Reserved
0000 Guard Time
0000b
Value used by the Contact UART notably in transmission mode.
The Contact UART will wait this number of ETUs before transmitting the
character.
In protocol T=1, gtr = FFh means operation at 11 ETUs.
In protocol T=0, gtr = FFh means operation at 12 ETUs.
All information provided in this document is subject to legal disclaimers.
Rev. 1.4 — 14 May 2018
314514
UM10858
PN7462 family HW user manual
© NXP B.V. 2018. All rights reserved.
218 of 345