Apr 2, 2007 ... APPLICATION NOTE. Page 1 of 7. 1. Abstract. The following article introduces
and shows an example of how to use the AD Converter (8-bit ...
APPLICATION NOTE
38D2 Group AD Converter (8-bit A/D Mode) 1. Abstract The following article introduces and shows an example of how to use the AD Converter (8-bit A/D Mode) on the 38D2 Group device.
2. Introduction The application explained in this document applies to the following MCU: Applicable MCU: 38D2 Group This sample program may include operations of unused bit functions for the convenience of the SFR bit layout. Set the values according to the operational conditions of the user system.
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38D2 Group AD Converter (8-bit A/D Mode) 3. Contents 3.1 Analog Signal Read in 8-bit A/D Mode Outline: The analog input voltage from a sensor is converted to digital values. Specifications: •The analog input voltage from a sensor is converted to digital values. •The P40/AN0 pin is used as an analog input pin. •8-bit A/D mode Figure 3.1 shows a Connection Diagram, Figure 3.2 shows the Relevant Register Settings, and Figure 3.3 shows the Control Procedure.
P40/AN0
Sensor
38D2 Group
Figure 3.1
Connection Diagram
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38D2 Group AD Converter (8-bit A/D Mode)
P o rt P 4 d ire c tio n re g is te r (a d d re s s : 0 0 0 9 h ) b7
b0 0
P4D
P 4 0 /A N 0 : In p u t m o d e P U L L re g is te r (a d d re s s : 0 F F 0 h ) b7 PULL
b0
0
0
P 4 0 to P 4 3 : N o p u ll-u p O s c illa tio n o u tp u t c o n tro l re g is te r (a d d re s s : 0 0 1 0 h ) b7 OSCOUT
0
b0 0
0
0
0
0
0
0
P 4 0 /P 4 3 o s c illa tio n o u tp u t c o n tro l: P 4 1 , P 4 0
n o rm a l p o rt
A /D c o n tro l re g is te r (a d d re s s : 0 0 1 5 h ) b7 ADCON
0
b0 1
0
1
0
0
0
A n a lo g in p u t p in s : S e le c t A N 0 0: A /D c o n v e rs io n c o m p le tio n b it ⎨ 1 :
A /D c o n v e rs io n s ta rts A /D c o n v e rs io n c o m p le te d (N o te 1 )
A D K E Y e n a b le b it: D is a b le d 1 0 -b it o r 8 -b it c o n v e rs io n s w itc h b it: S e le c t 8 -b it A /D A D K E Y s e le c tio n b it: V a lid A D c o n v e rs io n re g is te r (lo w -o rd e r) (a d d re s s : 0 0 1 6 h ) b7 ADL
0
b0 0
0
0
0
0
0
0
V R E F in p u t s w itc h b it ⎨ 0 : A U T O 1: O N A D c o n v e rs io n re g is te r (h ig h -o rd e r) (a d d re s s : 0 0 1 7 h ) b7 ADH
b0
b7 b6 b5 b4 b3 b2 b1 b0
(R e a d -o n ly ) S to re A /D c o n v e rs io n re s u lts (N o te 2 )
In te rru p t re q u e s t re g is te r 2 (a d d re s s : 0 0 3 D h ) b7 IR E Q 2
0
b0 0
N o A /D c o n v e rs io n in te rru p t re q u e s t is s u e d In te rru p t c o n tro l re g is te r 2 (a d d re s s : 0 0 3 F h ) b7 IC O N 2
0
b0 1
A /D c o n v e rs io n in te rru p t e n a b le d N o te s: 1 . A /D c o n v e rs io n is s ta rte d w h e n A /D c o n v e rs io n c o m p le tio n b it is s e t to 0 . O n ly 0 is v a lid w h e n w ritin g to A /D c o n v e rs io n c o m p le tio n b it a n d e v e n if 1 is w ritte n , th is b it is n o t s e t to 1 . T h e re fo re , w h e n w ritin g v a lu e to A D C O N w ith o u t a ffe c tin g A /D c o n v e rs io n c o m p le tio n b it, s e t A /D c o n v e rs io n c o m p le tio n b it to 1 . 2 . R e a d th e A /D c o n v e rs io n re s u lt a fte r A D c o n v e rs io n c o m p le tio n b it is s e t to 1 . W h e n re a d in g th e A /D c o n v e rs io n re s u lt in 8 -b it A /D m o d e , re a d th e A D c o n v e rs io n h ig h -o rd e r re g is te r o n ly .
Figure 3.2
Relevant Register Settings
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38D2 Group AD Converter (8-bit A/D Mode)
• X : N ot used in this application. S et to 0 or 1 according to use. O SO U T (address: 0010h) ← 00000000b P 4D (address: 0009h) ← X X X X X X X0b PU LL (address: 0FF 0h) ← 0X X X X 0X X b IC O N 2 (address: 003F h), bit 6 ← 0 AD C O N (address: 0015h) ← 010X 1000b AD L (address: 0016h) ← 00000000b NOP IR EQ 2 (address: 003D h), bit 6 ← 0 IC O N 2 (address: 003Fh), bit 6 ← 1 AD C O N (address: 0015h), bit 3 ← 0 C LI
• P 4 0 /AN 0 pin: N orm al port • P 4 0 /AN 0 pin: Input m ode • P 4 0 /AN 0 pin: N o pull-up • A /D conversion interrupt disabled • S elect A N 0 pin • V R E F input sw tich A U TO • • • •
N o A /D conversion interrupt request issued A /D conversion interrupt enabled S tart A /D conversion Interrupt enabled
A /D conversion interrupt routine C LT C LD P ush registers to the stack
R ead data of A D H (address: 0017h)
• Set X index m ode flag • S et decim al m ode flag • P ush registers used in interrupt routine to the stack
• R ead conversion results
≈ • Pop registers from the stack P op registers
R TI
Figure 3.3
Control Procedure
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38D2 Group AD Converter (8-bit A/D Mode) 4. Sample Programming Code Download a sample program from the Renesas Technology website. To download, click “Application Notes” in the left side menu on the page of the 38D2 Group.
5. Reference Datasheet 38D2 Group Datasheet Download the latest version from the Renesas Technology website. Technical News/Technical Update Download the latest information from the Renesas Technology website.
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38D2 Group AD Converter (8-bit A/D Mode) Website and Support Renesas Technology website http://www.renesas.com Inquiries http://www.renesas.com/inquiry
[email protected]
REVISION HISTORY
Rev.
Date
1.00
Feb 9, 2007
38D2 Group AD Converter (8-bit A/D Mode) Description
Page
REJ05B0990-0100/Rev.1.00
−
Summary First Edition issued
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38D2 Group AD Converter (8-bit A/D Mode)
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