PIC16C71X
7.9
Transfer Function
FIGURE 7-6: A/D TRANSFER FUNCTION
The ideal transfer function of the A/D converter is as fol-
lows: the first transition occurs when the analog input
voltage (VAIN) is Analog VREF/256 (Figure 7-6).
7.10
References
FFh
FEh
A very good reference for understanding A/D convert-
ers is the "Analog-Digital Conversion Handbook" third
edition, published by Prentice Hall (ISBN 0-13-03-
2848-0).
04h
03h
02h
01h
00h
Analog input voltage
FIGURE 7-7: FLOWCHART OF A/D OPERATION
ADON = 0
Yes
ADON = 0?
No
Acquire
Selected Channel
Yes
GO = 0?
No
Yes
Yes
Start of A/D
Conversion Delayed
1 Instruction Cycle
Finish Conversion
SLEEP
Instruction?
A/D Clock
= RC?
GO = 0
ADIF = 1
No
No
Yes
Yes
Abort Conversion
GO = 0
Wake-up
From Sleep?
Finish Conversion
Device in
SLEEP?
Wait 2 TAD
GO = 0
ADIF = 1
ADIF = 0
No
No
SLEEP
Power-down A/D
Finish Conversion
Stay in Sleep
Power-down A/D
Wait 2 TAD
GO = 0
ADIF = 1
Wait 2 TAD
1997 Microchip Technology Inc.
DS30272A-page 45
MICROCHIP [ MICROCHIP ]
