Source Code

Complete source code for both MAX110.EXE and

110CODE.MAX is provided on disk. MAX110.EXE was

written using Borland C++ version 3.0, and

110CODE.MAX was written using the Avocet 8051

Macro Assembler.

The most relevant subroutine in 110CODE.ASM is

Config110 (see Listing 1). This subroutine writes the

configuration word while simultaneously reading the

data from the MAX110 EV kit. Note that the configura-

tion word does not take effect until the next read/write

operation. Macros have been used to help make the

subroutine easier to understand.

Figures 1 and 2 show the timing specifications. The

80C32 module uses an 11.0592MHz clock, so the

instruction cycle time is 1.085µs per instruction cycle.

SCK must be low before

–

C

—

S

–

is activated. SCK’s pulse

width is 4.35µs, with period 17.33µs. The most signifi-

cant bit is sent first. Configuration data is valid 1.14µs

before the rising edge of SCK. Data from the MAX110

is sampled while SCK is high.

The communication protocol used between MAX110.EXE

and 110CODE is very simple. MAX110.EXE sets up a

configuration word by sending “Cxxxx”, where xxxx

represents the hexadecimal configuration word value.

MAX110.EXE then sends the “R” command, which

writes and reads the MAX110, and prints the hexadeci-

mal value it reads from the EV kit.

Note that the RAM resident code 110CODE.MAX resets

the MAX110 EV kit by sending three configuration bytes

in order: 8C8Ch, 8C88h, and 8C80h. These configura-

tion words reset the MAX110 by turning on auto-null

and gain-calibration mode together, then turning off

auto null, and finally turning off gain calibration. The

MAX110 internally divides the 1.024MHz crystal oscilla-

tor clock by two, for an effective clock of 512kHz. The

program uses the 16-bit resolution mode, unless other-

wise instructed by the user.

Source files SERCMD.C and MAX110.C form the core

interface to the MAX110 EV kit. To write your own pro-

grams using these files, read example programs

SIMPLE.C and NOISE.CPP, and the header files

SERCMD.H and MAX110.H. Both SERCMD and

MAX110 may be compiled under C or C++.

MAX110 Evaluation System/Evaluation Kit

8

_______________________________________________________________________________________

PIN No.

80C32

MAX110

FUNCTION

1–4

GND

GND

Ground

7, 8

+5V

+5V

+5V Supply to MAX110 EV Kit

27

P1.0

–

C

—

S

–

Active-Low Chip Select to MAX110

28

P1.1

SCK

Rising-Edge Clock Input to MAX110

29

P1.2

DIN

Serial Data Input to MAX110

30

P1.3

DOUT

Serial Data Output from MAX110

31

P1.4

–

B

—

U

—

S

—

Y

–

Active-Low Busy Output from MAX110

Table 10. Data-Connector Interface