CS7615-KQ Просмотр технического описания (PDF) - Cirrus Logic

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CS7615-KQ

CCD Imager Analog Processor

Cirrus Logic 

CS7615

SERIAL CONTROL BUS

The serial control bus protocol is an 8-bit protocol

controlled receiver. To the receiver, the control bus

looks like an 8-bit bi-directional channel down

which short packets are sent or received. Each

source device appears to the receiver as a set of 8-

bit registers, which are addressable to a device

through a station address. Packets are used to write

and read the contents of these device registers.

There are three packet formats: WRITE format,

ADDRESS SET format, and READ format. Each

packet is addressed to a device by its station ad-

dress. The LSB of the station address is the data di-

rection bit. This bit is set LOW in the WRITE and

ADDRESS SET packets, and it is set HIGH for

READ packets. The receiver can read and write to

non-existent registers within the selected device.

WRITE operations will have no effect; READ op-

erations will return a value of 00h.

Station Address

The CS7615 rev A default station address is A8h

for writes and A9h for reads. Subsequent versions

of the CS7615, starting with rev B, will use a de-

fault station address of 68h for writes and 69h for

reads.

The station address can be changed by writing a

new base station address to internal I2C register

FEh. Note that the station address register de-

scribes only the 7 MSBs of the CS7615 station ad-

dress. The base write address will need to be right

shifted by one place before being written into the

FEh register.

Write Operations

The WRITE format consists of a three-byte packet.

The first byte is the station address with the data di-

rection bit set LOW to indicate a write. The second

byte is the device register address (0..255). The

third byte is the register data (0..255). No extra

bytes should be sent.

Byte Sequence

First Byte

Second Byte

Third Byte

WRITE Format Packet Detail

Station Address

with LSB Set LOW

Device Register Address (0..255)

Register Data (0..255)

Table 3. WRITE Format Packet

Address Set Operation

The ADDRESS SET format consists of a two-byte

packet which sets the address of a subsequent

READ operation. The first byte of the station Ad-

dress with the LSB (data direction bit) set LOW to

indicate a write operation. The second byte is the

register address (0..255). The ADDRESS SET for-

mat is the same as the WRITE format, without the

register data.

Byte Sequence

First Byte

Second Byte

ADDRESS SET format

Packet Details

Station Address

with LSB Set LOW

Device Register Address (0..255)

Table 4. ADDRESS SET Format Packet Operation

Read Operations

The READ operation consist of two or more bytes.

The first byte is the station address with the LSB

(data direction bit) set HIGH indicating a read op-

eration. The addressed device then sends one or

more bytes back from the register last addressed by

the previous WRITE operation, or ADDRESS SET

operation.

Byte Sequence

First Byte

Second Byte

READ Format Packet Details

Station Address with LSB set

HIGH; Source Device then

Returns One Byte of Register

Data (0..255)

Returned data from CS7615

Table 5. READ Format Packet.

16

DS231PP6

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