TDA8029 Datasheet, PDF (19/59 Pages) NXP Semiconductors – Low power single card reader

Philips Semiconductors
TDA8029
Low power single card reader
9397 750 14145
Product data sheet
The 8-bit mode is called mode 1. In this mode the RI flag will be set if SM2 is enabled and
the information received has a valid stop bit following the 8 address bits and the
information is either a given or a broadcast address.
Mode 0 is the shift register mode and SM2 is ignored.
Using the automatic address recognition feature allows a master to selectively
communicate with one or more slaves by invoking the given slave address or addresses.
All of the slaves may be contacted by using the broadcast address. Two special function
registers are used to define the slave addresses, SADDR, and the address mask,
SADEN. SADEN is used to define which bits in the SADDR are to be used and which bits
are ‘don’t cares’. The SADEN mask can be logically AND-ed with the SADDR to create
the given address which the master will use for addressing each of the slaves. Use of the
given address allows multiple slaves to be recognized while excluding others. The
following examples will help to show the versatility of this scheme.
Table 18: Slave 0 address definition; example 1
Register
Value (binary)
SADDR
1100 0000
SADEN
1111 1101
Given
1100 00X0
Table 19: Slave 1 address definition; example 1
Register
Value (binary)
SADDR
1100 0000
SADEN
1111 1110
Given
1100 000X
In the above example SADDR is the same and the SADEN data is used to differentiate
between the two slaves. Slave 0 requires that bit 0 = 0 and ignores bit 1. Slave 1 requires
that bit 1 = 0 and bit 0 is ignored. A unique address for slave 0 would be 1100 0010 since
slave 1 requires bit 1 = 0. A unique address for slave 1 would be 1100 0001 since bit 0 = 1
will exclude slave 0. Both slaves can be selected at the same time by an address which
has bit 0 = 0 (for slave 0) and bit 1 = 0 (for slave 1). Thus, both could be addressed with
1100 0000.
In a more complex system the following could be used to select slaves 1 and 2 while
excluding slave 0.
Table 20: Slave 0 address definition; example 2
Register
Value (binary)
SADDR
1100 0000
SADEN
1111 1001
Given
1100 0XX0
Table 21: Slave 1 address definition; example 2
Register
Value (binary)
SADDR
1110 0000
SADEN
1111 1010
Given
1110 0X0X
Rev. 03 — 22 February 2005
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
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