attiny25v ATMEL Corporation, attiny25v Datasheet - Page 107

• Manufacturer Part Number: attiny25v
• Description: Microcontroller With 2/4/8k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

13.3.8
2586K–AVR–01/08
PLLCSR – PLL Control and Status Register
• Bit 6 - OCF1A: Output Compare Flag 1A
The OCF1A bit is set (one) when compare match occurs between Timer/Counter1 and the data
value in OCR1A - Output Compare Register 1A. OCF1A is cleared by hardware when executing
the corresponding interrupt handling vector. Alternatively, OCF1A is cleared, after synchroniza-
tion clock cycle, by writing a logic one to the flag. When the I-bit in SREG, OCIE1A, and OCF1A
are set (one), the Timer/Counter1 A compare match interrupt is executed.
• Bit 2 - TOV1: Timer/Counter1 Overflow Flag
The bit TOV1 is set (one) when an overflow occurs in Timer/Counter1. TOV1 is cleared by hard-
ware when executing the corresponding interrupt handling vector. Alternatively, TOV1 is
cleared, after synchronization clock cycle, by writing a logical one to the flag. When the SREG I-
bit, and TOIE1 (Timer/Counter1 Overflow Interrupt Enable), and TOV1 are set (one), the
Timer/Counter1 Overflow interrupt is executed.
• Bit 0 - Res: Reserved Bit
This bit is a reserved bit in the ATtiny25/45/85 and always reads as zero.
• Bit 6:3- Res : Reserved Bits
These bits are reserved bits in the ATtiny25/45/85 and always read as zero.
• Bit 2 - PCKE: PCK Enable
The bit PCKE is always set in the ATtiny15 compatibility mode.
• Bit 1 - PLLE: PLL Enable
The PLL is always enabled in the ATtiny15 compatibility mode.
• Bit 0 - PLOCK: PLL Lock Detector
When the PLOCK bit is set, the PLL is locked to the reference clock. The PLOCK bit should be
ignored during initial PLL lock-in sequence when PLL frequency overshoots and undershoots,
before reaching steady state. The steady state is obtained within 100 µs. After PLL lock-in it is
recommended to check the PLOCK bit before enabling PCK for Timer/Counter1.
Bit
0x27
Read/Write
Initial value
LSM
R/W
7
0
R
6
0
-
R
5
0
-
R
4
0
-
R
3
0
-
PCKE
R/W
2
0
ATtiny25/45/85
PLLE
R/W
0/1
1
PLOCK
R
0
0
PLLCSR
107