Rainbow Electronics ATmega128RFA1 - Manual (Page 288)

288
8266A-MCU Wireless-12/09
ATmega128RFA1
Register Bits Value Description
0x4 CTC, TOP = OCRnA
0x5 Fast PWM, 8-bit
0x6 Fast PWM, 9-bit
0x7 Fast PWM, 10-bit
0x8 PWM, Phase and frequency correct, TOP =
ICRn
0x9 PWM, Phase and frequency correct, TOP =
OCRnA
0xA PWM, Phase correct, TOP = ICRn
0xB PWM, Phase correct, TOP = OCRnA
0xC CTC, TOP = OCRnA
0xD Reserved
0xE Fast PWM, TOP = ICRn
0xF Fast PWM, TOP = OCRnA
• Bit 2:0 – CS42:40 - Clock Select
The three clock select bits select the clock source to be used by the Timer/Counter4
according to the following table. External pin modes cannot be used for the
Timer/Counter4.
Table 18-23 CS4 Register Bits
Register Bits Value Description
0x00 No clock source (Timer/Counter stopped)
0x01 clk_IO/1 (no prescaling)
0x02 clk_IO/8 (from prescaler)
0x03 clk_IO/64 (from prescaler)
0x04 clk_IO/256 (from prescaler)
0x05 clk_IO/1024 (from prescaler)
0x06 Reserved
CS42:40
0x07 Reserved
18.11.33 TCCR4C – Timer/Counter4 Control Register C
Bit 7 6 5 4 3 2 1 0
NA ($A2) FOC4A FOC4B FOC4C Res4 Res3 Res2 Res1 Res0 TCCR4C
Read/Write RW RW RW R R R R R
Initial Value 0 0 0 0 0 0 0 0
• Bit 7 – FOC4A - Force Output Compare for Channel A
The FOC4A bit is only active when the WGM43:0 bits specify a non-PWM mode. When
writing a logical one to the FOC4A bit, an immediate compare match is forced. Due to
the limited functionality of the Timer/Counter4 the match has no direct impact on any
output pin. Note that the FOC4A bits are implemented as strobes. Therefore it is the
value present in the COM4A1:0 bits that determine the effect of the forced compare. A
FOC4A strobe will not generate any interrupt nor will it clear the timer in Clear Timer on