HT46RU22 Holtek Semiconductor Inc., HT46RU22 Datasheet - Page 23

• Manufacturer Part Number: HT46RU22
• Description: Ht46ru22 -- A/d Type 8-bit Mcu
• Manufacturer: Holtek Semiconductor Inc.

Low Voltage Reset - LVR
The microcontroller provides 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~3.3V, such as changing a battery, the LVR will au-
tomatically reset the device internally.
The LVR includes the following specifications:
The relationship between V
Note: V
Note:
Rev. 1.20
The low voltage (0.9V~V
original state to exceed 1ms. If the low voltage state
does not exceed 1ms, the LVR will ignore it and do not
perform a reset function.
The LVR uses the OR function with the external RES
signal to perform chip reset.
operation at 4MHz system clock.
OPR
*1: To make sure that the system oscillator has stabilized, the SST provides an extra delay of 1024 system
*2: Since low voltage state has to be maintained in its original state for over 1ms, therefore after 1ms delay,
is the voltage range for proper chip
clock pulses before entering the normal operation.
the device enters the reset mode.
DD
LVR
and V
) has to remain in their
LVR
is shown below.
Low Voltage Reset
23
I
I
bidirectional 2-wire lines. The data line and clock line
are implement in SDA pin and SCL pin. The SDA and
SCL are NMOS open drain output pin. They must con-
nect a pull-high resistor respectively.
Using the I
data. One is in slave transmit mode, the other is in slave
receive mode. There are four registers related to I
Bus; HADR([20H]), HCR([21H]), HSR([22H]),
HDR([23H]). The HADR register is the slave address
setting of the device, if the master sends the calling ad-
dress which match, it means that this device is selected.
The HCR is I
device enable or disable the I
as a receiver. The HSR is I
sponds with the I
data register, data to transmit or receive must be via the
HDR register.
The I
HEN bit define the enable or disable the I
data wants transfer via I
HTX bit defines whether the I
ceive mode. If the device is as a transmitter, this bit must
be set to 1 . The TXAK defines the transmit acknowl-
edge signal, when the device received 8-bit data, the
device sends this bit to I
ceiver wants to continue to receive the next data, this bit
must be reset to 0 before receiving data.
2
2
C Bus Serial Interface
C Bus is implemented in the device. The I
2
C Bus control register contains three bits. The
2
C Bus, the device has two ways to transfer
2
C Bus control register which defines the
2
C Bus status. The HDR is input/output
2
2
C Bus at the 9th clock. If the re-
C Bus, this bit must be set. The
2
C Bus status register, it re-
2
2
C Bus is in transmit or re-
C Bus as a transmitter or
HT46RU22
March 23, 2007
2
C Bus. If the
2
C Bus is a
2
C