Cirrus-logic AN131 Bedienungsanleitung PDF herunterladen (Seite 5)

AN131

AN131REV2 5

5. CONCLUSION

This application note presents an example of how

to interface the CS5521/22/23/24/28 to the

68HC05. It is divided into two main sections: hard-

ware and software. The hardware interface illus-

trates both three-wire and a four-wire interface.

The three-wire interface is SPI and Microwire™

compatible. The software section illustrates how to

initialize the converter and microcontroller, write

to the CSRs, write and read the ADC’s internal reg-

isters, perform calibrations, and acquire conver-

sions. The software is modularized and provides

important subroutines such as write_register,

read_register, write_csrs and convert, which were

all written in 68HC05 assembly language.

The software described in the note is included in

Section 6. “APPENDIX: 68HC05 Microcode to In-

terface to the CS5521/22/23/24/28” on page 6.

ommand Time

8SCLKs

SCLKs Clear SDO Flag

Data SDO Continuous Conversion Read

SCLK

SDI

ata Time

24 SCLKs

td = XIN/OWR clock cycles for each conversion except the

first conversion which will take XIN/OWR + 7 clock cycles

IN/OWR

Clock Cycles

Figure 5. Conversion/Acquisition Cycle Timing

MSB High-Byte

Mid-Byte

Low-Byte

A) 24-Bit Conversion Data Word (CS5522/24/28)

MSB High-Byte

Mid-Byte

Low-Byte

B) 16-Bit Conversion Data Word (CS5521/23)

0- always zero, 1- always one,

CI1, CI0 - Channel Indicator Bits

OD - Oscillation Detect, OF - Overflow

Figure 6. Bit Representation/Storage in 68HC05

D23 D22 D21 D20 D19 D18 D17 D16

D15 D14 D13 D12 D11 D10 D9 D8

D7 D6 D5 D4 D3 D2 D1 D0

D15 D14 D13 D12 D11 D10 D9 D8

D7 D6 D5 D4 D3 D2 D1 D0

1110CI1CI0ODOF

1 2 3 4 5 6 7 8 9 10 ... 13 14

Kommentare zu diesen Handbüchern

Keine Kommentare

Cirrus-logic AN131 Bedienungsanleitung Seite 5

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Hardware Cirrus-logic AN131