TDA8029 Datasheet, PDF (33/58 Pages) NXP Semiconductors – Low power single card reader

Philips Semiconductors
Low power single card reader
Product specification
TDA8029
8.10.2.3 Mixed Status Register (MSR)
This register relates the status of the card presence contact PR1, the BGT counter, the FIFO empty indication, the
transmit/receive ready indicator TBE/RBF and the completion of clock switching to or from ¹/₂f_int.
No bit within register MSR act upon INT0_N.
Table 48 Mixed status register, address Ch, read
BIT
7
6
5
4
Symbol
CLKSW
FE
BGT
−
Reset value
−
1
0
−
3
2
1
0
−
PR1
−
TBE/RBF
−
−
0
0
Table 49 Description of register bits
BIT
SYMBOL
DESCRIPTION
7
CLKSW
Clock Switch. CLKSW is set when the TDA8029 has performed a required clock switch
from ¹/_nf_XTAL to ¹/₂f_int and is reset when the TDA8029 has performed a required clock
switch from ¹/₂f_int to ¹/_nf_XTAL. The application shall wait this bit before entering
power-down mode or restarting sending commands after leaving power-down (only
needed when the clock is not stopped during power-down). This bit is also reset by RIU
and at power-on. When the microcontroller wants to transmit a character to the card, it
writes the data in direct convention to this register.
6
FE
FIFO Empty. FE is set when the reception FIFO is empty. It is reset when at least one
character has been loaded in the FIFO.
5
BGT
Block Guard Time.
In T = 1 protocol, the bit BGT is linked with a 22 ETU counter, which is started at every
start-bit on pin I/O. If the count is finished before the next start-bit, BGT is set. This helps
checking that the card has not answered before 22 ETU after the last transmitted
character, or that the reader is not transmitting a character before 22 ETU after the last
received character.
4 and 3 −
2
PR1
1
−
In T = 0 protocol, the bit BGT is linked to a 16 ETU counter, which is started at every
start-bit on I/O. If the count is finished before the next start-bit, then the bit BGT is set.
This helps checking that the reader is not transmitting too early after the last received
character.
Not used.
Presence 1. PR1 = 1 when the card is present.
Not used.
2003 Oct 30
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