ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 142

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

17.4
17.4.1
142
Register Description
Atmel ATmega48PA/88PA/168PA [Preliminary]
GTCCR – General Timer/Counter Control Register
• Bit 7 – TSM: Timer/Counter Synchronization Mode
Writing the TSM bit to one activates the Timer/Counter Synchronization mode. In this mode,
the value that is written to the PSRASY and PSRSYNC bits is kept, hence keeping the corre-
sponding prescaler reset signals asserted. This ensures that the corresponding
Timer/Counters are halted and can be configured to the same value without the risk of one of
them advancing during configuration. When the TSM bit is written to zero, the PSRASY and
PSRSYNC bits are cleared by hardware, and the Timer/Counters start counting
simultaneously.
• Bit 0 – PSRSYNC: Prescaler Reset
When this bit is one, Timer/Counter1 and Timer/Counter0 prescaler will be Reset. This bit is
normally cleared immediately by hardware, except if the TSM bit is set. Note that
Timer/Counter1 and Timer/Counter0 share the same prescaler and a reset of this prescaler
will affect both timers.
Bit
0x23 (0x43)
Read/Write
Initial Value
TSM
R/W
7
0
R
6
–
0
R
5
–
0
R
4
–
0
R
3
–
0
R
2
–
0
PSRASY
R/W
1
0
PSRSYNC
R/W
9223B–AVR–09/11
0
0
GTCCR