COMBOSMARTMETER datasheet(35/60 Pages) TI1

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Hi-Z

START

DRDY

SCLK

DIN

DOUT

RDATA Opcode

Status Register + n-Channel Data (216 Bits)

RDATA Opcode

ADS131E04

ADS131E06

ADS131E08

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SBAS561A – JUNE 2012 – REVISED APRIL 2013

SDATAC: Stop Read Data Continuous

This opcode cancels the Read Data Continuous mode. There are no SCLK rate restrictions for this command,

but the following command must wait for 4 tCLK cycles to execute.

RDATA: Read Data

Issue this command after DRDY goes low to read the conversion result (in Stop Read Data Continuous mode).

There are no SCLK rate restrictions for this command, and there is no wait time needed for subsequent

commands or data retrieval SCLKs. To retrieve data from the device after the RDATA command is issued, make

sure either the START pin is high or the START command is issued. When reading data with the RDATA

command, the read operation can overlap the next DRDY occurrence without data corruption. Figure 40 shows

the recommended way to use the RDATA command. RDATA is best suited for systems where register settings

must be read or changed often between conversion cycles.

Figure 40. RDATA Usage

Sending Multibyte Commands

The ADS131E0x serial interface decodes commands in bytes and requires 4 tCLK cycles to decode and execute.

Therefore, when sending multibyte commands, a 4-tCLK period must separate the end of one byte (or opcode)

and the next.

Assuming SCLK is 2.048 MHz, then tSDECODE (4 tCLK) is 1.96 µs. When SCLK is 16 MHz, one byte can be

transferred in 500 ns. This byte transfer time does not meet the tSDECODE specification; therefore, a delay must be

inserted so the end of the second byte arrives 1.46 µs later. If SCLK is 4 MHz, one byte is transferred in 2 µs.

Because this transfer time exceeds the tSDECODE specification, the processor can send subsequent bytes without

delay. In this later scenario, the serial port can be programmed to move from single-byte transfers per cycle to

multiple bytes.

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Product Folder Links: ADS131E04 ADS131E06 ADS131E08

COMBOSMARTMETER Datasheet(PDF) 35 Page - Texas Instruments