Datasheet

 1997 Microchip Technology Inc. DS30272A-page 45
PIC16C71X
7.9 Transfer Function
The ideal transfer function of the A/D converter is as fol-
lows: the first transition occurs when the analog input
voltage (V
AIN) is Analog VREF/256 (Figure 7-6).
7.10 References
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).
FIGURE 7-6: A/D TRANSFER FUNCTION
Digital code output
FFh
FEh
04h
03h
02h
01h
00h
0.5 LSb
1 LSb 2 LSb 3 LSb 4 LSb
255 LSb 256 LSb
(full scale)
Analog input voltage
FIGURE 7-7: FLOWCHART OF A/D OPERATION
Acquire
ADON = 0
ADON = 0?
GO = 0?
A/D Clock
GO = 0
ADIF = 0
Abort Conversion
SLEEP
Power-down A/D
Wait 2 T
AD
Wake-up
Yes
No
Yes
No
No
Yes
Finish Conversion
GO = 0
ADIF = 1
Device in
No
Yes
Finish Conversion
GO = 0
ADIF = 1
Wait 2 TAD
Stay in Sleep
Selected Channel
= RC?
SLEEP
No
Yes
Instruction?
Start of A/D
Conversion Delayed
1 Instruction Cycle
From Sleep?
Power-down A/D
Yes
No
Wait 2 TAD
Finish Conversion
GO = 0
ADIF = 1
SLEEP?