A
PPLICATION NOTE
M16C/62 Group
A-D Converter OP-AMP Gain Adjustment Connection Mode
1. Abstract
This application note describes the operation of gain adjustment by using operational amplifier for A-D converter.
2. Introduction
This application note is applied to the M16C/62 group Microcomputers.
This program can be also operated under the condition of M16C family products with the same SFR (Special Function
Register) as M16C/62 Group products. Because some functions may be modified of the M16C family products, see the user’s
manual. When using the functions shown in this application note, evaluate them carefully for an operation.
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M16C/62 Group
A-D Converter OP-AMP Gain Adjustment Connection Mode
3. Detailed description
This example describes the operation of gain adjustment by using external operational amplifier for M16C/62 group
microcomputers.
3.1 Example of wiring
Figure 1 illustrates the operation of gain adjustment by using external operational amplifier.
380k
330k
270k
220k
170k
150k
120k
100k
7
+5V
VCC
VCC
VREF
N7
N6
N5
N4
N3
N2
N1
N0
NEX0
NEX1
VSS
VSS
M16C/62 group
100k
BA4558
100k
6
+
5
Input
100k
+12V
2
8
-
+
3
1
4
-12V
Figure1. Example of wiring
Note
(1)In this example, using 2nd inverting amplified circuit, feedback to in-phase.
The result shows a difference from this sample when use non-inverting amplified circuit.
(2)In this example, values input to AN0 to AN7 are amplified as below, due to the ratio of the value of resistance.
AN0: 100k/100k=1 (1 time amplified)
AN1: 120k/100k=1.2 (1.2 times amplified)
AN2: 150k/100k=1.5 (1.5 time amplified)
AN3: 170k/100k=1.7 (1.7 times amplified)
AN4: 220k/100k=2.2 (2.2 times amplified)
AN5: 270k/100k=2.7 (2.7 times amplified)
AN6: 330k/100k=3.3 (3.3 times amplified)
AN7: 380k/100k=3.8 (3.8 times amplified)
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A-D Converter OP-AMP Gain Adjustment Connection Mode
3.2 How to set up
This section shows the setting procedures when A-D conversion is carried out, for the output of the gain adjustment, by using
external operational amplifier. Examples of A-D conversion with sample & hold function for one-shot mode and 10-bit mode are
described.
(1) Setting ADCON2 register (A-D control register 2)
Setting A-D conversion method and frequency select bit
1
b0 b7
0
SMP: A-D conv ersi o n met hod sel e ct bit
"0": Without sample & hold
"1": With sample & hold
DGSEL1-0: A-D input group select bit (Note 1)
CKS2: Frequency selected bit 2 (Note 1,2)
Note 1: Only applied to M16C/62P group. For other group please set to "00".
Note 2: Select the frequency of φAD for M16C/62P group according to the following combination.
CKS2 CKS1 CKS0
0 0 0 Divided-by-4 of fAD
0 0 1 Divided-by-2 of fAD
0 1 0
0 1 1
1 0 0 Divided-by-12 of fAD
1 0 1 Divided-by-6 of fAD
1 1 0
1 1 1
fAD
Divided-by-3 of fAD
"00": Select port P10 group
"01": Don’t set it
"10": Select port P0 group
"11": Select port P2 group
"0": fAD, fAD divided by 2 or fAD divided by 4 is selected
"1": fAD divided by 3, fAD divided by 6 or fAD divided by 12
is selected
φAD
(2) Setting ADCON0 register (A-D control register 0)
Analog input pin select bit, A-D operation mode, frequency select bit
b0 b7
0 0 0 0
CH2 to 0: Analog input pin select bit
Set input pin for A-D conversion
MD1 to 0: A-D operation mode select bit 0
Set to "00" (one-shot mode)
TRG: Trigger select bit
Set to "0" (Software trigger)
DST: A-D conversion start flag
CKS0: Frequency select bit 0 (Note 3)
Note 3: Refer to "3.2 (1) Note 2" for details the setting example for M16C/62P group.
Set to "0" (A-D conversion disabled)
"0": fAD divided by 4 is selected
"1": fAD divided by 2 is selected
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M16C/62 Group
A-D Converter OP-AMP Gain Adjustment Connection Mode
(3) Setting ADCON1 register (A-D control register 1)
Setting A-D operation mode select bit 1, 8/10-bit mode select bit, frequency select bit 1, external op- amp connection
mode bit.
b0b7
0 1 1 1 1
SCAN1 to 0: A-D sweep pin select bit
Invalid in one-shot mode
MD2: A-D operation mode select bit 2
BITS: 8/10 bit mode select bit
CKS1: Frequency select bit 1 (Note 1)
VCUT: VREF connection bit
OPA1 to OPA0: External op-amp connection mode bit
Note 1: Refer to "3.2 (1) Note 2" for details the setting example for M16C/62P group.
Set to "0"
Set to "1" (10-bit mode)
"0": fAD divided by 2 or fAD divided by 4 is selected
"1": fAD is selected
Set to "1" (VREF connected)
Set to "11" (External op-amp connection mode)
(4) ADIC register (A-D interrupt control register)
b0 b7
0 0 0 0 0
ILVL2 to 0: Interrupt priority level select bit
Select interrupt priority select level
IR : Interrupt request bit
No interrupt requested
(5) Waiting until external op-amp operation is stable
Waiting until external op-amp operation is stable. (Varied from the op-amp being used)
In the wiring example of 3.1, it takes 50µs until input value to ANEX1 pin becomes stable.
About 50µs
Input to ANEX1 pin
(6) A-D conversion start
A-D conversion start when setting ADST bit of ADCON0 register to "1".
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(7) Waiting for A-D conversion complete
Wait until IR bit in ADIC register reaches to "1" (interrupt request).
(8) Reading of result of A-D conversion
Read A-D register i (i=0 to 7) corresponding to selected pin in analog input select bit.
M16C/62 Group
A-D Converter OP-AMP Gain Adjustment Connection Mode
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A-D Converter OP-AMP Gain Adjustment Connection Mode
4. Reference
Hardware Manual
M16C/62 group (M16C/62P) Hardware Manual Rev.1.11
M16C/62 group data sheet Rev.H2
M16C/62A group data sheet Rev.C1
M16C/62N group data sheet Rev.1.1
(Use the latest version on the web-site: http://www.renesas.com)
User’s Manual
M16C/62 group User’s Manual Rev.C3
M16C/62A group User’s Manual Rev.1.0
(Use the latest version on the web-site: http://www.renesas.com)
5. Web-site and contact for support
Renesas web-site
http://www.renesas.com/
Contact for Renesas technical support
E-mail: support_apl@renesas.com
M16C/62 Group
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A-D Converter OP-AMP Gain Adjustment Connection Mode
6. The example of a reference program
The following program shows a sequential reading of gain amplified value from AN0 to AN7 by connecting to external
operational amplifier.
;**********************************************************************
;
; M16C/62 Group Program Collection
;
; FILE NAME : rjj05b0441_src.a30
; CPU : M16C/62 Group
; FUNCTION : The example of A-D conversion at the time of external
; operational amplifier gain adjustment
; HISTORY : 2004.01.15 Ver 1.00
;
; Copyright (C) 2004. Renesas Technology Corp.
; Copyright (C) 2004. Renesas Solutions Corp.
; All right reserved.
;
;**********************************************************************
; ----- include define ---- .list off
.include sfr62p.inc
.list on
;
; ----- Symbol define ----vstack .equ 0002b00h ; Stack Pointer
vram .equ 0000400h ; Internal RAM area
vram_end .equ 0002c00h ;
vpro .equ 00fc000h ; Program Start address
vval_vec .equ 00ffd00h ; Variable vector address
vvector .equ 00fffdch ; Non-maskable vector address
;
; ----- Internal RAM Area ---- .section ramdata,data
.org vram
;
; ----- Program Area ---- .section program,code
.org vpro
reset:
;
; ----- Initial setting ---- ldc #vstack,sp ; Set stack-pointer address
ldintb #vval_vec ; Set variable vector table address
;
mov.b #003h, prcr
mov.b #008h, cm0
mov.b #020h, cm1 ; main-clock divid by 0 mode
mov.b #000h, prcr
mov.w #00000h, p0
mov.w #0ffffh, pd0 ; Port0/1 output select
mov.w #00000h, p2
mov.w #0ffffh, pd2 ; Port2/3 output select
mov.w #00000h, p4
mov.w #0ffffh, pd4 ; Port4/5 output select
mov.w #00000h, p6
mov.w #0ffffh, pd6 ; Port6/7 output select
bset prc2
mov.b #000h, pd9 ; P9_5(ANEX0) & P9_6(ANEXq) is input port
mov.b #000h, pd10 ; P10_0(AN0) to P10_7(AN7) is input port
;
;----- Evaluation start ----start:
mov.b #00000001b, adcon2
; | ||+--------------------- conversion mode select : sample&hold
; | ++---------------------- input group select : select P10 group
; +------------------------- Freq select bit2 : fAD/2
mov.b #10000000b, adcon0
; |||||+++--------------------- input select : AN0 select
; |||++------------------------ mode select bit0 : single mode
; ||+-------------------------- trigger select : software
; |+--------------------------- AD start flag : stop
; +---------------------------- Freq select bit0 : fAD/2
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A-D Converter OP-AMP Gain Adjustment Connection Mode
mov.b #11100000b, adcon1
; ||||||++--------------------- sweep pin select : none
; |||||+----------------------- mode select bit1 : 0 fix
; ||||+------------------------ 8/10 bit select : 8bit
; |||+------------------------- Freq select bit1 : fAD/2
; ||+-------------------------- VREF connect bit : VREF connect
; ++--------------------------- Ext ope-amp connect mode : Ext ope-amp connebt
mov.b #007h,adic ; set AD interrupt prioliry level
main_loop:
;
; ----- AN0 conversion -----
bclr adst ; AD conversion stop
mov.b #10000000b, adcon0
jsr AD_wait
bset adst ; AD conversion start
an0_wait: ; wait for AN0 conversion complate
btst ir_adic
jnc an0_wait
bclr ir_adic ; AD interrupt req clear
mov.b ad0, p0 ; conversion result display
;
; ----- AN1 conversion ---- bclr adst ; AD conversion stop
mov.b #10000001b, adcon0
; +++--------------------- input select : AN1 select
jsr AD_wait
bset adst ; AD conversion start
an1_wait: ; wait for AN1 conversion complate
btst ir_adic
jnc an1_wait
bclr ir_adic ; AD interrupt req clear
mov.b ad1, p1 ; conversion result display
;
; ----- AN2 conversion ---- bclr adst ; AD conversion stop
mov.b #10000010b, adcon0
; +++--------------------- input select : AN2 select
jsr AD_wait
bset adst ; AD conversion start
an2_wait: ; wait for AN2 conversion complate
btst ir_adic
jnc an2_wait
bclr ir_adic ; AD interrupt req clear
mov.b ad2, p2 ; conversion result display
;
; ----- AN3 conversion ---- bclr adst ; AD conversion stop
mov.b #10000011b, adcon0
; +++--------------------- input select : AN3 select
jsr AD_wait
bset adst ; AD conversion start
an3_wait: ; wait for AN3 conversion complate
btst ir_adic
jnc an3_wait
bclr ir_adic ; AD interrupt req clear
mov.b ad3, p3 ; conversion result display
;
; ----- AN4 conversion ---- bclr adst ; AD conversion stop
mov.b #10000100b, adcon0
; +++--------------------- input select : AN4 select
jsr AD_wait
bset adst ; AD conversion start
M16C/62 Group
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A-D Converter OP-AMP Gain Adjustment Connection Mode
an4_wait: ; wait for AN4 conversion complate
btst ir_adic
jnc an4_wait
bclr ir_adic ; AD interrupt req clear
mov.b ad4, p4 ; conversion result display
;
; ----- AN5 conversion ---- bclr adst ; AD conversion stop
mov.b #10000101b, adcon0
; +++--------------------- input select : AN5 select
jsr AD_wait
bset adst ; AD conversion start
an5_wait: ; wait for AN5 conversion complate
btst ir_adic
jnc an5_wait
bclr ir_adic ; AD interrupt req clear
mov.b ad5, p5 ; conversion result display
;
; ----- AN6 conversion ---- bclr adst ; AD conversion stop
mov.b #10000110b, adcon0
; +++--------------------- input select : AN6 select
jsr AD_wait
bset adst ; AD conversion start
an6_wait: ; wait for AN6 conversion complate
btst ir_adic
jnc an6_wait
bclr ir_adic ; AD interrupt req clear
mov.b ad6, p6 ; conversion result display
;
; ----- AN7 conversion ---- bclr adst ; AD conversion stop
mov.b #10000111b, adcon0
; +++--------------------- input select : AN7 select
jsr AD_wait
bset adst ; AD conversion start
an7_wait: ; wait for AN7 conversion complate
btst ir_adic
jnc an7_wait
bclr ir_adic ; AD interrupt req clear
mov.b ad7, p7 ; conversion result display
; ----- AD conversion complated -----
mov.b #0ffh, pd8
mov.b #0ffh, p8
end_loop:
jmp end_loop ; Infinity loop
;
; ----- Opeamp wakeup wait routine ----AD_wait:
mov.b #000b, ta0mr ; for Opeamp wakeup wait
mov.w #1600-1, ta0 ; 100us(16MHz,f1)
bset ta0s ; TA0 start
ta0_wait:
btst ir_ta0ic ; TA0 overflow wait
jnc ta0_wait
bclr ir_ta0ic
rts
;
;----- Evaluation end ----;
;/////////////////////////////////////////////////////////////////////
; interrupt routine
;/////////////////////////////////////////////////////////////////////
dummyi: ; Dummy interrupt routine
;
nop
nop
nop
nop
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A-D Converter OP-AMP Gain Adjustment Connection Mode
reit
;
;/////////////////////////////////////////////////////////////////////
; Non-maskable interrupt routine
;/////////////////////////////////////////////////////////////////////
undi: ; Undefined instruction interrupt
ovfli: ; Overflow interrupt
brki: ; BRK instruction interrupt
addri: ; Address match interrupt
wdti: ; Watch-dog timer interrupt
nmii: ; NMI interrupt
;
nop
nop
nop
nop
reit
;
;/////////////////////////////////////////////////////////////////////
; Variale vector table
;/////////////////////////////////////////////////////////////////////
.section val_vector,romdata
.org vval_vec
;
.lword dummyi ; 0=BRK instruction interrupt
.lword dummyi ; 1=
.lword dummyi ; 2=
.lword dummyi ; 3=
.lword dummyi ; 4=^INT3 interrupt
.lword dummyi ; 5=TB5 interrupt
.lword dummyi ; 6=TB4/Uart1 bus collision interrupt
.lword dummyi ; 7=TB3/Uart0 bus collision interrupt
.lword dummyi ; 8=SIO4/^INT5 interrupt
.lword dummyi ; 9=SIO3/^INT4 interrupt
.lword dummyi ;10=Uart2 bus collision interrupt
.lword dummyi ;11=DMA0 interrupt
.lword dummyi ;12=DMA1 interrupt
.lword dummyi ;13=KEY input interrut
.lword dummyi ;14=AD interrupt
.lword dummyi ;15=Uart2 transmit/NACK2 interrupt
.lword dummyi ;16=Uart2 receive/ACK2 interrupt
.lword dummyi ;17=Uart0 transmit/NACK0 interrupt
.lword dummyi ;18=Uart0 receive/ACK0 interrupt
.lword dummyi ;19=Uart1 transmit/NACK1 interrupt
.lword dummyi ;20=Uart1 receive/ACK1 interrupt
.lword dummyi ;21=TA0 interrupt
.lword dummyi ;22=TA1 interrupt
.lword dummyi ;23=TA2 interrupt
.lword dummyi ;24=TA3 interrupt
.lword dummyi ;25=TA4 interrupt
.lword dummyi ;26=TB0 interrupt
.lword dummyi ;27=TB1 interrupt
.lword dummyi ;28=TB2 interrupt
.lword dummyi ;29=^INT0 interrupt
.lword dummyi ;30=^INT1 interrupt
.lword dummyi ;31=^INT2 interrupt
.lword dummyi ;32=
.lword dummyi ;33=
.lword dummyi ;34=
.lword dummyi ;35=
.lword dummyi ;36=
.lword dummyi ;37=
.lword dummyi ;38=
.lword dummyi ;39=
.lword dummyi ;40=
.lword dummyi ;41=
.lword dummyi ;42=
.lword dummyi ;43=
.lword dummyi ;44=
.lword dummyi ;45=
.lword dummyi ;46=
.lword dummyi ;47=
.lword dummyi ;48=
.lword dummyi ;49=
.lword dummyi ;50=
.lword dummyi ;51=
.lword dummyi ;52=
.lword dummyi ;53=
.lword dummyi ;54=
.lword dummyi ;55=
.lword dummyi ;56=
.lword dummyi ;57=
.lword dummyi ;58=
.lword dummyi ;59=
.lword dummyi ;60=
.lword dummyi ;61=
.lword dummyi ;62=
M16C/62 Group
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A-D Converter OP-AMP Gain Adjustment Connection Mode
.lword dummyi ;63=
;
;/////////////////////////////////////////////////////////////////////
; Non-Maskable interrupt vector table
;/////////////////////////////////////////////////////////////////////
.section vector,romdata
.org vvector
;
.lword undi ; ffffdc to f Undefined instruction interrupt
.lword ovfli ; ffffe0 to 3 Overflow interrupt
.lword brki ; ffffe4 to 7 BRK instruction interrupt
.lword addri ; ffffe8 to b Address match interrupt
.lword dummyi ; ffffec to f
.lword wdti ; fffff0 to 3 Watch-dog timer interrupt
.lword dummyi ; fffff4 to 7
.lword nmii ; fffff8 to b NMI interrupt
.lword reset ; fffffc to f RESET
;
.end
M16C/62 Group
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Revision history
M16C/62 Group
A-D Converter OP-AMP Gain Adjustment Connection Mode
Rev. Issue date
1.00 2004.03.18 - First edition issued
Revised
Page Point
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A-D Converter OP-AMP Gain Adjustment Connection Mode
Keep safety first in your circuit designs!
Keep safety first in your circuit designs!
1. Renesas Technology Corporation puts the maximum effort into making semiconductor products
better and more reliable, but there is always the possibility that trouble may occur with them. Trouble
with semiconductors may lead to personal injury, fire or property damage.
Remember to give due consideration to safety when making your circuit designs, with appropriate
measures such as (i) placement of substitutive, auxiliary circuits, (ii) use of nonflammable material or
(iii) prevention against any malfunction or mishap.
M16C/62 Group
Notes regarding these materials!
Notes regarding these materials
1. These materials are intended as a reference to assist our customers in the selection of the Renesas
Technology Corporation product best suited to the customer's application; they do not convey any
license under any intellectual property rights, or any other rights, belonging to Renesas Technology
Corporation or a third party.
2. Renesas Technology Corporation assumes no responsibility for any damage, or infringement of any
third-party's rights, originating in the use of any product data, diagrams, charts, programs,
algorithms, or circuit application examples contained in these materials.
3. All information contained in these materials, including product data, diagrams, charts, programs and
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subject to change by Renesas Technology Corporation without notice due to product improvements
or other reasons. It is therefore recommended that customers contact Renesas Technology
Corporation or an authorized Renesas Technology Corporation product distributor for the latest
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Renesas Technology Corporation assumes no responsibility for any damage, liability, or other loss
rising from these inaccuracies or errors.
Please also pay attention to information published by Renesas Technology Corporation by various
means, including the Renesas Technology Corporation Semiconductor home page
(http://www.renesas.com).
4. When using any or all of the information contained in these materials, including product data,
diagrams, charts, programs, and algorithms, please be sure to evaluate all information as a total
system before making a final decision on the applicability of the information and products. Renesas
Technology Corporation assumes no responsibility for any damage, liability or other loss resulting
from the information contained herein.
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device or system that is used under circumstances in which human life is potentially at stake.
Please contact Renesas Technology Corporation or an authorized Renesas Technology Corporation
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REJ05B0442-0100Z/Rev.1.00
March 2004
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