SC16IS752IPW datasheet(39/59 Pages) NXP

39 / 59 page

SC16IS752_SC16IS762_7

Product data sheet

Rev. 07 — 19 May 2008

39 of 59

NXP Semiconductors

SC16IS752/SC16IS762

Dual UART with I2C-bus/SPI interface, 64-byte FIFOs, IrDA SIR

10.3 Addressing

Before any data is transmitted or received, the master must send the address of the

receiver via the SDA line. The ﬁrst byte after the START condition carries the address of

the slave device and the read/write bit. Table 32 shows how the SC16IS752/SC16IS762’s

address can be selected by using A1 and A0 pins. For example, if these 2 pins are

connected to VDD, then the SC16IS752/SC16IS762’s address is set to 0x90, and the

master communicates with it through this address.

[1]

X = logic 0 for write cycle; X = logic 1 for read cycle.

10.4 Use of subaddresses

When a master communicates with the SC16IS752/SC16IS762 it must send a

subaddress in the byte following the slave address byte. This subaddress is the internal

address of the word the master wants to access for a single byte transfer, or the beginning

of a sequence of locations for a multi-byte transfer. A subaddress is an 8-bit byte. Unlike

the device address, it does not contain a direction (R/W) bit, and like any byte transferred

on the bus it must be followed by an acknowledge.

A register write cycle is shown in Figure 18. The START is followed by a slave address

byte with the direction bit set to ‘write’, a subaddress byte, a number of data bytes, and a

STOP signal. The subaddress indicates which register the master wants to access, and

the data bytes which follow will be written one after the other to the subaddress location.

Table 33 and Table 34 show the bits’ presentation at the subaddress byte for I2C-bus and

SPI interfaces. Bit 0 is not used, bits 2:1 select the channel, bits 6:3 select one of the

UART internal registers. Bit 7 is not used with the I2C-bus interface, but it is used by the

SPI interface to indicate a read or a write operation.

Table 32.

SC16IS752/SC16IS762 address map

SC16IS752/SC16IS762 I2C address (hex)[1]

VDD

0x90 (1001 000X)

VDD

VSS

0x92 (1001 001X)

VDD

SCL

0x94 (1001 010X)

VDD

SDA

0x96 (1001 011X)

VSS

VDD

0x98 (1001 100X)

VSS

0x9A (1001 101X)

VSS

SCL

0x9C (1001 110X)

VSS

SDA

0x9E (1001 111X)

SCL

VDD

0xA0 (1010 000X)

SCL

VSS

0xA2 (1010 001X)

SCL

0xA4 (1010 010X)

SCL

SDA

0xA6 (1010 011X)

SDA

VDD

0xA8 (1010 100X)

SDA

VSS

0xAA (1010 101X)

SDA

SCL

0xAC (1010 110X)

SDA

0xAE (1010 111X)

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