13.4 Programmable Clock-Out from UART2 Baud Rate Timer
Using the UART2 Baud Rate Timer, a 50% duty cycle clock can be programmed to come out from pin S2CKO
(P3.5). The clock-out frequency depends on the system clock frequency (Fosc) and the reload value filled in the
S2BRT register, as shown in the following formula:
Fosc
Clock-Out Frequency =
n x (256-S2BRT)
Where,
n=24 if S2X12=0,
n=2 if S2X12=1.
The UART2 Baud Rate Timer is programmed for the clock-out mode as follows:
• Set S2CKOE bit in AUXR2 register.
• Determine the 8-bit reload value from the formula and enter it in S2BRT register.
• Start the timer by setting the run control bit S2TR in AUXR2 register.
Figure 13-2. Programmable Clock-Out from UART2 Baud Rate Timer
Fosc
D
Clock-Out
(P3.5)
Q
Q
12
"0"
"1"
Overflow
Counter
(8 Bits)
CK
S2TR
S2X12
S2BRT
(8 Bits)
MEGAWIN
MPC82G516A Data Sheet
66
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
