PIC16C712/716
8.4 A/D Conversions
Note: The GO/DONE bit should NOT be set in
the same instruction that turns on the A/D.
8.5 Use of the CCP Trigger
An A/D conversion can be started by the “special event
trigger” of the CCP1 module. This requires that the
CCP1M3:CCP1M0 bits (CCP1CON<3:0>) be pro-
grammed as 1011 and that the A/D module is enabled
(ADON bit is set). When the trigger occurs, the
TABLE 8-2 SUMMARY OF A/D REGISTERS
GO/DONE bit will be set, starting the A/D conversion,
and the Timer1 counter will be reset to zero. Timer1 is
reset to automatically repeat the A/D acquisition period
with minimal software overhead (moving the ADRES to
the desired location). The appropriate analog input
channel must be selected and the minimum acquisition
done before the “special event trigger” sets the
GO/DONE bit (starts a conversion).
If the A/D module is not enabled (ADON is cleared),
then the “special event trigger” will be ignored by the
A/D module, but will still reset the Timer1 counter.
Address Name
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR,
BOR
Value on all
other Resets
05h
PORTA
—
—
—(1)
RA4
RA3
RA2
RA1
RA0 --xx xxxx
0Bh,8Bh INTCON GIE PEIE T0IE INTE RBIE
T0IF
INTF RBIF 0000 000x
0Ch
PIR1
—
ADIF
—
—
—
CCP1IF TMR2IF TMR1IF -0-- -000
1Eh
ADRES A/D Result Register
xxxx xxxx
1Fh
ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE —
ADON 0000 00-0
85h
TRISA
—
—
—(1) PORTA Data Direction Register
---1 1111
8Ch
PIE1
—
ADIE
—
—
—
CCP1IE TMR2IE TMR1IE -0-- -000
9Fh
ADCON1 —
—
—
—
—
PCFG2 PCFG1 PCFG0 ---- -000
Legend: x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used for A/D conversion.
Note 1: Reserved bits; Do Not Use.
--xu uuuu
0000 000u
-0-- -000
uuuu uuuu
0000 00-0
---1 1111
-0-- 0000
---- -000
DS41106A-page 50
Preliminary
© 1999 Microchip Technology Inc.