Rainbow Electronics ATmega163L - Manual (Page 89)

ATmega163(L)
89
• Bit 3 - ACIE: Analog Comparator Interrupt Enable
When the ACIE bit is set (one) and the I-bit in the Status Register is set (one), the analog comparator interrupt is activated.
When cleared (zero), the interrupt is disabled.
•
Bit 2 - ACIC: Analog Comparator Input Capture Enable
When set (one), this bit enables the Input Capture function in Timer/Counter1 to be triggered by the analog comparator.
The comparator output is in this case directly connected to the Input Capture front-end logic, making the comparator utilize
the noise canceler and edge select features of the Timer/Counter1 Input Capture interrupt. When cleared (zero), no con-
nection between the analog comparator and the Input Capture function is given. To make the comparator trigger the
Timer/Counter1 Input Capture interrupt, the TICIE1 bit in the Timer Interrupt Mask Register (TIMSK) must be set (one).
•
Bits 1,0 - ACIS1, ACIS0: Analog Comparator Interrupt Mode Select
These bits determine which comparator events that trigger the Analog Comparator interrupt. The different settings are
shown in Table 37.
When changing the ACIS1/ACIS0 bits, The Analog Comparator Interrupt must be disabled by clearing its Interrupt Enable
bit in the ACSR register. Otherwise an interrupt can occur when the bits are changed.
Analog Comparator Multiplexed Input
It is possible to select any of the PA7..0 (ADC7..0) pins to replace the negative input to the analog comparator. The ADC
multiplexer is used to select this input, and consequently, the ADC must be switched off to utilize this feature. If the Analog
Comparator Multiplexer Enable bit (ACME in SFIOR) is set (one) and the ADC is switched off (ADEN in ADCSR is zero),
MUX2..0 in ADMUX select the input pin to replace the negative input to the Analog Comparator, as shown in Table 38. If
ACME is cleared (zero) or ADEN is set (one), PB3 (AIN1) is applied to the negative input to the Analog Comparator.
Table 37. ACIS1/ACIS0 Settings
ACIS1 ACIS0 Interrupt Mode
0 0 Comparator Interrupt on Output Toggle
0 1 Reserved
1 0 Comparator Interrupt on Falling Output Edge
1 1 Comparator Interrupt on Rising Output Edge
Table 38. Analog Comparator Multiplexed Input
ACME ADEN MUX2..0 Analog Comparator Negative Input
0 x xxx AIN1
1 1 xxx AIN1
1 0 000 ADC0
1 0 001 ADC1
1 0 010 ADC2
1 0 011 ADC3
1 0 100 ADC4
1 0 101 ADC5
1 0 110 ADC6
1 0 111 ADC7