GMS81C1404 Datasheet, PDF (51/93 Pages) Hynix Semiconductor – 8-BIT SINGLE-CHIP MICROCONTROLLERS

GMS81C1404/GMS81C1408
If it needed more higher frequency of PWM, it should be
reduced resolution.
Resolution
T1CK[1:0] =
00(125nS)
Frequency
T1CK[1:0] =
01(250nS)
T1CK[1:0] =
10(1uS)
10-bit
7.8KHz
3.9KHz
0.98KHZ
9-bit
15.6KHz
7.8KHz
1.95KHz
8-bit
31.2KHz
15.6KHz
3.90KHz
7-bit
62.5KHz
31.2KHz
7.81KHz
Table 13-2 PWM Frequency vs. Resolution at 8MHz
The bit POL of TM1 decides the polarity of duty cycle.
If the duty value is set same to the period value, the PWM
output is determined by the bit POL (1: High, 0: Low). And
if the duty value is set to “00_H”, the PWM output is deter-
mined by the bit POL (1: Low, 0: High).
It can be changed duty value when the PWM output. How-
ever the changed duty value is output after the current pe-
riod is over. And it can be maintained the duty value at
present output when changed only period value shown as
Figure 13-12 . As it were, the absolute duty time is not
changed in varying frequency. But the changed period val-
ue must greater than the duty value.
Note: If changing the Timer1(3) to PWM function, it
should be stop the timer clock firstly, and then
set period and duty register value. If user
writes register values while timer is in opera-
tion, these register could be set with certain
values.
Ex)
LDM TM1,#00H
LDM T1PPR,#00H
LDM T1PDR,#00H
LDM PWM0HR,#00H
LDM RBFUNC,#0001_1100B
LDM TM1,#1010_1011B
TM1
PWM0HR
POL
X
-
-
16BIT
0
-
-
PWME
CAP1
T1CK1 T1CK0 T1CN
T1ST
ADDRESS : D2H
RESET VALUE : 00000000
1
0
X
X
X
X
ADDRESS : D5H
-
-
PWM0HR3 PWM0HR2 PWM0HR1 PWM0HR0
RESET VALUE : ----0000
Bit Manipulation Not Available
-
-
X
X
X
X
Period High
Duty High
PWM0HR[3:2]
X: The value “0” or “1” corresponding your operation.
T0 clock source
T1ST
0 : Stop
1 : Clear and Start
T1PPR(8-bit)
COMPARATOR
CLEAR
1
MUX
÷1
T1 (8-bit)
fxin
÷2
÷8
COMPARATOR
T1CK[1:0]
T1CN
Slave
T1PDR(8-bit)
SQ
R
POL
PWM0O
[RBFUNC.4]
RB4/
PWM0
PWM0HR[1:0]
Master
T1PDR(8-bit)
Figure 13-10 PWM Mode
June. 2001 Ver 1.2
49