HT48CA0-1 Holtek Semiconductor, HT48CA0-1 Datasheet - Page 9

• Manufacturer Part Number: HT48CA0-1
• Description: (HT48RA0-1 / HT48CA0-1) Remote Type 8-Bit MCU
• Manufacturer: Holtek Semiconductor

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The chip reset status of the registers is summarized in the following table:
Note:
To guarantee that the system oscillator has started and
stabilized, the SST (System Start-up Timer) provides an
extra-delay of 1024 system clock pulses when the sys-
tem powers up or when the system awakes from a HALT
state.
When a system power up occurs, an SST delay is added
during the reset period. But when the reset comes from
the RES pin, the SST delay is disabled. Any wake-up
from HALT will enable the SST delay.
The functional unit chip reset status is shown below.
Carrier
The HT48RA0-1/HT48CA0-1 provides a carrier output
which shares the pin with PC0. It can be selected to be a
carrier output (REM) or level output pin (PC0) by code
option. If the carrier output option is selected, setting
PC0= 0 to enable carrier output and setting PC0= 1 to
disable it at low level output.
Rev. 1.40
Program Counter
MP
ACC
TBLP
TBLH
STATUS
PA
PB
PC
Program Counter
WDT Prescaler
Input/Output ports
Stack Pointer
Carrier output
Register
u means unchanged
x means unknown
(Power On)
1111 1111
1111 1111
xxxx xxxx
xxxx xxxx
-xxx xxxx
--00 xxxx
--xx xxxx
000H
Clear
Input mode
Points to the top of the stack
Low level
---- ---1
Reset
000H
(Normal Operation)
WDT Time-out
uuuu uuuu
uuuu uuuu
1111 1111
1111 1111
-uuu uuuu
--uu uuuu
--1u uuuu
---- ---1
000H
Carrier/Level Output
9
(Normal Operation)
The clock source of the carrier is implemented by in-
struction clock (system clock divided by 4) and pro-
cessed by a frequency divider to yield various carry
frequency.
Carry Frequency=
where m=2 or 3 and n=0~3, both are selected by code
option. If m=2, the duty cycle of the carrier output is 1/2
duty. If m=3, the duty cycle of the carrier output can be
1/2 duty or 1/3 duty also determined by code option (with
the exception of n=0).
Detailed selection of the carrier duty is shown below:
The following table shows examples of carrier fre-
quency selection.
2, 4, 8, 16
3
6, 12, 24
455kHz
RES Reset
uuuu uuuu
uuuu uuuu
1111 1111
1111 1111
-uuu uuuu
--uu uuuu
--uu uuuu
f
SYS
---- ---1
000H
m 2
37.92kHz
f
56.9kHz
n
CARRIER
HT48RA0-1/HT48CA0-1
Clock Source
RES Reset
uuuu uuuu
uuuu uuuu
1111 1111
1111 1111
-uuu uuuu
m 2
--uu uuuu
--01 uuuu
(HALT)
---- ---1
000H
1/2
1/3
1/2 or 1/3
n
1/3 only
1/2 only
Duty
December 21, 2005
Duty Cycle
WDT Time-out
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
-uuu uuuu
--uu uuuu
--11 uuuu
(HALT)*
---- ---u
000H
m´2
3
2
n