HT45R35V Holtek Semiconductor Inc., HT45R35V Datasheet - Page 25
HT45R35V
Manufacturer Part Number
HT45R35V
Description
C/r To F Type 8-bit Otp Mcu
Manufacturer
Holtek Semiconductor Inc.
Datasheet
1.HT45R35V.pdf
(42 pages)
Programming Example
The following example shows how the VFD display data is programmed by the microcontroller.
strobe
clk
data
data_2_register:
data_2_register_1:
Low Voltage Reset - LVR
The microcontroller provides a low voltage reset circuit
in order to monitor the supply voltage of the device. If the
supply voltage of the device is within the range
0.9V~V
will automatically reset the device internally.
The LVR includes the following specifications:
Note:
Rev. 1.00
The low voltage (0.9V~V
nal state for longer than t
does not exceed t
perform a reset function.
The LVR uses an OR function with the external RES
signal to perform a chip reset.
mov
mov
clr
clr
set
snz
clr
rlc
rlc
rlc
set
sdz
jmp
set
ret
LVR
*1: To make sure that the system oscillator has stabilized, the SST provides an extra delay of 1024 system
*2: Since low voltage has to be maintained its original state for longer than t
, such as when changing a battery, the LVR
clock pulses before starting the normal operation.
the reset mode.
equ pb.5
equ pb.6
equ pb.7
a,024d
count,a
strobe
clk
data
vfd_grid.7
data
vfd_segl
vfd_segh
vfd_grid
clk
count
data_2_register_1
strobe
LVR
, the LVR will ignore it and will not
LVR
LVR
) has to remain in its origi-
; send data to vfd driver
; shift register counter
; strobe = 0
; clk = 0
; data = 1
; data = 0
; shift data to vfd[7:0]
; shift data to vfd[15:8]
; shift data to vfd[22:16]
; clk = 1 (rising edge)
; strobe = 1, vfd output
. If the low voltage state
Low Voltage Reset
25
The relationship between V
Note:
V
operation at 4MHz system clock.
OPR
is the voltage range for proper chip
LVR
, therefore a t
DD
and V
LVR
LVR
January 15, 2009
HT45R35V
is shown below.
delay enters