HMS87C1808B Datasheet, PDF (55/99 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

HMS87C1X04B/08B/16B
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 12-1 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 determined by the bit
POL (1: Low, 0: High).
It can be changed duty value when the PWM output. However the
changed duty value is output after the current period is over and
it can be maintained the duty value at present output when
changed only period value shown as Figure 12-12 . As it were, the
absolute duty time is not changed in varying frequency. But the
changed period value must greater than the duty value.
Note: If changing the Timer1 to PWM function, the
timer should be stop and set to PWM mode (PWME
= 1) firstly, and then set period and duty register val-
ue. When user writes register values while timer is in
operation, these register could be set with certain val-
ues. If user sets the T1PPR, T1PDR register value
with PWM mode being disabled, the T1PPR and
T1PDR can not be accessed because these registers
act as TDR1 and T1/CDR1 register in non-PWM
mode.
Ex)
LDM TM1,#0010_0000b
LDM T1PPR,#0EH
LDM T1PDR,#05H
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 : 0000_0000
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
fxin
÷2
÷8
T1 (8-bit)
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 12-10 PWM Mode
SEP. 2004 Ver 1.03
51