s3c72m9 Samsung Semiconductor, Inc., s3c72m9 Datasheet - Page 288

• Manufacturer Part Number: s3c72m9
• Description: The S3c72m5/s3c72m7/s3c72m9 Single-chip Cmos Microcontroller Has Been Designed For High Performance Using Samsung S
• Manufacturer: Samsung Semiconductor, Inc.

TIMERS and TIMER/COUNTERS
TC1A CLOCK FREQUENCY OUTPUT
Using timer/counter 1A, a modifiable clock frequency can be output to the TC1A clock output pin, TCLO1. To select
the clock frequency, load the appropriate values to the TC1A mode register, TMOD1A. The clock interval is selected
by loading the desired reference value into the 8-bit reference register TREF1A. To enable the output to the TCLO1
pin at I/O port 3.1, the following conditions must be met:
— TC1A output enable flag TOE1 must be set to "1".
— I/O mode flag for P3.1 (PM3.1) must be set to output mode ("1").
— P3.1 output latch must be cleared to "0".
In summary, the operational sequence required to output a TC1A-generated clock signal to the TCLO1 pin is as
follows:
1. Set the TMOD1A.7 to "0" to be operated as timer/counter 1A.
2. Load your reference value to TREF1A.
3. Set the internal clock frequency in TMOD1A.
4. Initiate TC1A clock output to TCLO1 (TMOD1A.2 = "1").
5. Set port 3.1 mode flag (PM3.1) to "1".
6. Clear the P3.1 output latch.
7. Set TOE1 flag to "1".
Each time TCNT1A overflows and an interrupt request is generated, the state of the output latch TOL1 is inverted and
the TC1A-generated clock signal is output to the TCLO1 pin.
F
Output a 30 ms pulse width signal to the TCLO1 pin:
11-40
PROGRAMMING TIP — TC1A Signal Output to the TCLO1 Pin
BITS
SMB
LD
LD
LD
LD
LD
LD
BITR
BITS
EMB
15
EA,#79H
TREF1A,EA
EA,#04CH
TMOD1A,EA
EA,#02H
PMG2,EA
P3.1
TOE1
; P3.1
; P3.1 clear
S3C72M5/C72M7/C72M9/P72M9 (Preliminary Spec)
output mode