AN420

Application example

Doc ID 2078 Rev 2

11/15

5

Application example

An example ST62 software program follows on the next pages. It executes the program flow

of Figure 3 in the application circuit of Figure 4.

Figure 4.

Example circuit

The ST6215 pin allocation is arbitrary. The three outputs can drive other identical circuits,

when more the one 10-bit A/D channel is needed. Also, a different number of 'pieces' can be

used to achieve a different resolution.

;***********************************************************************************

;* File name: HIRES_AD.ASM

;*

;* ALGEBRAIC ADDER AND ST6 A/D CONVERTERS - Application note software

;* This software is an example on how to increase the ST6 converter

;* resolution. Please refer to the application note for further

;* explanations.

;*

;* Allocation of pins: PC4, PC5 and PC6 are, respectively, voltage sources

;* VN1, VN2 and VN3. PB0 is an A/D input

;*

;***********************************************************************************

.input "6215_reg.asm" ;ST6215 standard definitions file

VN1 .equ 4

;PC4 bit select

VN2 .equ 5

;PC5 bit select

VN3 .equ 6

;PC6 bit select

drcs .def 0bfh,0ffh,0ffh

;shadow register for Data Register C

PC4

3.3K

5K

10K

10K

PC5

PC6

ST6215

PB0 (A/D Input)

2K

5K

Vin

OUTPUTS