Timer/Counter1 Control Register B - Tccr1B - Atmel AVR AT90S2313 Manual

Timer/Counter1 Control
Register B – TCCR1B
AT90S2313
32
direction control bit must be set (one) to control an output pin. The control configuration
is shown in Table 8.
Table 8. Compare 1 Mode Select
COM1A1 COM1A0
0 0
0 1
1 0
1 1
Note: In PWM mode, these bits have a different function. Refer to Table 12 for a detailed
description.
• Bits 5..2 – Res: Reserved Bits
These bits are reserved bits in the AT90S2313 and always read zero.
• Bits 1,0 – PWM11, PWM10: Pulse Width Modulator Select Bits
These bits select PWM operation of Timer/Counter1 as specified in Table 9. This mode
is described on page 35.
Table 9. PWM Mode Select
PWM11 PWM10
0 0
0 1
1 0
1 1
Bit 7 6
$2E ($4E) ICNC1 ICES1
Read/Write R/W R/W
Initial value 0 0
• Bit 7 – ICNC1: Input Capture1 Noise Canceler (4 CKs)
When the ICNC1 bit is cleared (zero), the input capture trigger noise canceler function is
disabled. The input capture is triggered at the first rising/falling edge sampled on the ICP
(input capture pin) as specified. When the ICNC1 bit is set (one), four successive sam-
ples are measured on the ICP (input capture pin), and all samples must be high/low
according to the input capture trigger specification in the ICES1 bit. The actual sampling
frequency is the XTAL clock frequency.
• Bit 6 – ICES1: Input Capture1 Edge Select
While the ICES1 bit is cleared (zero), the Timer/Counter1 contents are transferred to the
Input Capture Register (ICR1) on the falling edge of the input capture pin (ICP). While
the ICES1 bit is set (one), the Timer/Counter1 contents are transferred to the Input Cap-
ture Register (ICR1) on the rising edge of the input capture pin (ICP).
• Bits 5, 4 – Res: Reserved Bits
These bits are reserved bits in the AT90S2313 and always read zero.
Description
Timer/Counter1 disconnected from output pin OC1
Toggle the OC1 output line.
Clear the OC1 output line (to zero).
Set the OC1 output line (to one).
Description
PWM operation of Timer/Counter1 is disabled
Timer/Counter1 is an 8-bit PWM
Timer/Counter1 is a 9-bit PWM
Timer/Counter1 is a 10-bit PWM
5 4 3
– – CTC1
R R R/W
0 0 0
2 1 0
CS12 CS11 CS10 TCCR1B
R/W R/W R/W
0 0 0
0839G–08/01