at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 128

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

13.18.1
13.18.2
13.18.3
128
AT90PWM81
Available Input Mode according to Running Mode
Event Capture
Using the Input Capture Unit
Some Input Modes are not consistent with some Running Modes. So the table below gives the input
modes which are valid according to running modes.
Table 13-8.
The PSC can capture the value of time (PSC counter) when a retrigger event or fault event occurs on PSC
inputs. This value can be read by software in PICRnH/L register.
The main challenge when using the Input Capture unit is to assign enough processor capacity for handling
the incoming events. The time between two events is critical. If the processor has not read the captured
value in the PICR1 Register before the next event occurs, the PICR1 will be overwritten with a new value.
In this case the result of the capture will be incorrect.
When using the Input Capture interrupt, the PICR1 Register should be read as early in the interrupt han-
dler routine as possible. Even though the Input Capture interrupt has relatively high priority, the maximum
interrupt response time is dependent on the maximum number of clock cycles it takes to handle any of the
other interrupt requests.
Input Mode Number
:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Available Input Modes according to Running Modes
1 Ramp Mode
Valid
Do not use
Do not use
Valid
Do not use
Do not use
Valid
Valid
Valid
Do not use
Valid
Do not use
2 Ramp Mode
Valid
Valid
Valid
Valid
Valid
Valid
Valid
Valid
Valid
Valid
4 Ramp Mode
Valid
Valid
Valid
Valid
Valid
Valid
Valid
Valid
Valid
Valid
Centered Mode
Do not use
Do not use
Do not use
Valid
Do not use
Do not use
Valid
Do not use
Do not use
Do not use
7734M–AVR–03/10