TDA8029HLSLASHC2 datasheet(20/58 Pages) PHILIPS

20 / 58 page

2003 Oct 30

Philips Semiconductors

Product speciﬁcation

Low power single card reader

TDA8029

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 15 Slave 0

Table 16 Slave 1

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 bit1=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 17 Slave 0

Table 18 Slave 1

Table 19 Slave 2

In the above example the differentiation among the

3 slaves is in the lower 3 address bits. Slave 0 requires

that bit0=0 and it can be uniquely addressed by

1110 0110. Slave 1 requires that bit1=0 and it can be

uniquely addressed by 1110 and 0101. Slave 2 requires

that bit2=0 and its unique address is 1110 0011.

To select slaves 0 and 1 and exclude slave 2 use address

1110 0100, since it is necessary to make bit 2 = 1 to

exclude slave 2.

The broadcast address for each slave is created by taking

the logical OR of SADDR and SADEN. Zeros in this result

are treated as don’t cares. In most cases, interpreting the

don’t cares as ones, the broadcast address will be FFh.

Upon reset SADDR (SFR address 0A9h) and SADEN

(SFR address 0B9h) are leaded with 0s. This produces a

given address of all ‘don’t cares’ as well as a broadcast

address of all ‘don’t cares’. This effectively disables the

automatic addressing mode and allows the microcontroller

to use standard 80C51 type UART drivers which do not

make use of this feature.

VALUE (BINARY)

SADDR

1100 0000

SADEN

1111 1101

Given

1100 00X0

VALUE (BINARY)

SADDR

1100 0000

SADEN

1111 1110

Given

1100 000X

VALUE (BINARY)

SADDR

1100 0000

SADEN

1111 1001

Given

1100 0XX0

VALUE (BINARY)

SADDR

1110 0000

SADEN

1111 1010

Given

1110 0X0X

VALUE (BINARY)

SADDR

1110 0000

SADEN

1111 1100

Given

1110 00XX

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