SC18IS602B Просмотр технического описания (PDF) - NXP Semiconductors.

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SC18IS602B

I²C-bus to SPI bridge

NXP Semiconductors. 

NXP Semiconductors

SC18IS602/602B/603

I2C-bus to SPI bridge

7.1.1 Addressing

R/W

slave address

Fig 5. Slave address

0 1 0 1 A2 A1 A0 X

fixed

programmable

002aac446

The first seven bits of the first byte sent after a START condition defines the slave address

of the device being accessed on the bus. The eighth bit determines the direction of the

message. A ‘0’ in the least significant position of the first byte means that the master will

write information to a selected slave. A ‘1’ in this position means that the master will read

information from the slave. When an address is sent, each device in a system compares

the first seven bits after the START condition with its address. If they match, the device

considers itself addressed by the master as a slave-receiver or slave-transmitter,

depending on the R/W bit.

A slave address of the SC18IS602/602B/603 is comprised of a fixed and a programmable

part. The programmable part of the slave address enables the maximum possible number

of such devices to be connected to the I2C-bus. Since the SC18IS602/602B/603 have

three programmable address bits (defined by the A2, A1, and A0 pins), it is possible to

have eight of these devices on the same bus.

The state of the A2, A1, and A0 pins are latched at reset. Changes made after reset will

not alter the address.

7.1.2 Write to data buffer

All communications to or from the SC18IS602/602B/603 occur through the data buffer.

The data buffer is 200 bytes deep. A message begins with the SC18IS60x address,

followed by the Function ID. Depending upon the Function ID, zero to 200 data bytes can

follow.

The SC18IS60x will place the data received into a buffer and continue loading the buffer

until a STOP condition is received. After the STOP condition is detected, further

communications will not be acknowledged until the function designated by the Function ID

has been completed.

S SLAVE ADDRESS W A

Fig 6. Write to data buffer

FUNCTION ID

A 0 TO 200 BYTES A P

002aac447

7.1.3 SPI read and write - Function ID 01h to 0Fh

Data in the buffer will be sent to the SPI port if the Function ID is 01h to 0Fh. The Function

ID contains the Slave Select (SS) to be used for the transmission on the SPI port. There

are four Slave Selects that can be used, with each SS being selected by one of the bits in

SC18IS602_602B_603_4

Product data sheet

Rev. 04 — 11 March 2008

© NXP B.V. 2008. All rights reserved.

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