Specifications

132
3706C–MICRO–2/11
AT89LP3240/6440
Notes:1.CONB (ACSRB.5) must be cleared to 0 before changing RFB[1-0].
2. CONA (ACSRA.5) must be cleared to 0 before changing RFA[1-0].
Table 19-3. AREF – Analog Comparator Reference Control Register
AREF = AFH Reset Value = 0000 0000B
Not Bit Addressable
CBC1 CBC0
RFB1 RFB0 CAC1 CAC0 RFA1 RFA0
Bit76543210
Symbol Function
CSC [1-0] Comparator B Clock Select
CBC1 CBC0 Clock Source
00System Clock
0 0 Timer 0 Overflow
0 1 Timer 1 Overflow
0 1 Timer 2 Overflow
RFB [1-0] Comparator B Negative Input Cha nnel Select
(1)
CRF1 RFB0 B- Channel
0 0 AIN2 (P2.6)
0 0 Internal V
AREF-Δ
(~1.2V)
0 1 Internal V
AREF
(~1.3V)
0 1 Internal V
AREF+Δ
(~1.4V)
CAC [1-0] Comparator A Clock Select
CAC1 CAC0 Clock Source
00System Clock
0 0 Timer 0 Overflow
0 1 Timer 1 Overflow
0 1 Timer 2 Overflow
RFA [1-0] Comparator A Negative Input Channel Select
(2)
RFA1 RFA0 A- Channel
0 0 AIN1 (P2.5)
0 0 Internal V
AREF-Δ
(~1.2V)
0 1 Internal V
AREF
(~1.3V)
0 1 Internal V
AREF+Δ
(~1.4V)