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Date: 20.04.04

Page 13 of 30

Title:

Data Sheet GC-IP200

Name of Document:

43500-DB-2-1-E-IP200.pdf

5.2.3

Synchronous / Asynchronous Mode

Read data is loaded into the hold register by the RD0/ST command. This takes place when the internal

sequential control counter and the SYNC register have the same contents (synchronous mode) or when the

ASYNC

bit is set (asynchronous mode). Pin SDO is low during the waiting time (meaning of RDY) .

With the SPI working in synchronous mode, the output data can be assigned to a sample time. Equidistant

measurement is possible (refer also to the application example). Higher transmission rates are achieved in

asynchronous mode.

Example: 32-bit read access synchronous with internal cycle counter

RD0 / ST

XXXXXX

SYNC

RDY

RD1

Byte 0 +1

RDY

RD0 / ST *)

Byte 2 + 3

SYNC

RDY

SEN

SDI

SDO

*) any command

Hold register

Data to be transmitted

Figure 8

Example: 16-bit read access, asynchronous, 3 channels

RD0 H1

RD0 H2

SEN

SDI

SDO

RD0 H0

RD0 H0

XXX

Data H0

Data H1

Data H2

Hold register channel 0

Data to be transmitted

Hold register channel 1

Data to be transmitted

Hold register channel 2

Data to be transmitted

Figure 9

Example: write access 1 Channel

WRD (data)

SEN

SDI

SDO

WRA (address)

XXX

XXX

Example: command execution 1 channel

SEN

SDI

SDO

WRC

(Command)

XXX

Execution of command

Figure 10

Figure 11