Download the Holtek HT LCD Controller Datasheet and browse our LCDs that use this controller. Version HT RAM Mapping 32 4 LCD Controller . HTB | HOLTEK | LCD Controller 4×32 segments | Drivers – Pricing and Availability. Description, RAM Mapping 32×4 LCD Controller For I/o uc. Company, Holtek Semiconductor Inc. Datasheet, Download HTB datasheet. Quote. Find where.

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Only three or four lines are required for the interface between the host controller and the HT The HT contains a power down command to reduce power consumption.

Download the Holtek HT1621 LCD Controller Datasheet

Chip selection BZ, BZ: X Y Pad No. The serial interface circuit is also reset. But if CS is at logic low level and is input to the CS pad, the data and command transmission between the host controller and the HT are all enabled. The clocked out gt1621b will appear on the Hltek line.

The host controller can use the next rising edge to latch the clocked out data. If the system clock comes from an external clock source, the external clock source should be connected to the OSCI pad.

These are stress ratings only. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.

If the VDD drops below the minimum voltage of operating voltage spec. But if the external clock source is chosen as the system clock, using the SYS DIS command can neither turn the oscillator off nor carry out the power down mode. The crystal oscillator option can be applied to connect an external frequency source of 32kHz to the OSCI pin. In this case, the system fails to enter the power down mode, similar to the case in the external kHz clock source operation.

The watch dog timer WDTon the other hand, is composed of an 8-stage time base generator along with a 2-stage count-up counter, and is designed to break the host controller or other subsystems from abnormal states such as unknown or unwanted jump, execution errors, etc. The outputs hoptek the time base generator and of the WDT time-out flag can be connected to the IRQ output by a command option.

There are totally eight frequency sources available for the time base generator and the WDT clock. The frequency is calculated by the following equation.


The 32kHz in the above equation indicates that the source of the system frequency is derived from a crystal oscillator of The source of the clock may be from ut1621b on-chip RC oscillator kHza crystal oscillator The configuration of the system oscillator is as shown. That command is, however, available only for the on-chip RC oscillator or for the crystal oscillator.

If an on-chip oscillator kHz or an external kHz frequency is chosen as the source of the system frequency, the frequency source is by default prescaled to 32kHz by a 3-stage prescaler.

Employing both the time base generator and the WDT related commands, one should be careful since the time base generator and WDT share the same 8-stage counter. The configuration of the time base generator along with the WDT are as shown.

In the case of hooltek RC oscillator or crystal oscillator, the power down mode can reduce power consumption since the oscillator can be turned on or off by the corresponding system commands. A simple tone generator is implemented in the HT The tone generator can output a pair of differential driving signals on the BZ and BZ, which are used to generate a single tone.

The tone outputs, namely BZ and BZ, are a pair of differential driving outputs used to drive a piezo buzzer. Once the system is disabled or the tone output is inhibited, the BZ and the BZ outputs will remain at low level. The LCD driving clock is derived from the system clock. The value of the driving clock is always Hz even when it is at a The LCD corresponding commands are summarized in the table.

The bold form goltek 1 0 0, namely 1 0 0, indicates the command mode ID. If successive commands have been issued, the command mode ID except for the first command, will be omitted. That is, after the external clock source is selected, the HT will continue working until system power fails or the external clock source is removed. After the system power on, the IRQ will be disabled. Data to be read or written or commands to be written have to be passed through the DATA line.

It is recommended that the host controller ht16211b in correct data during the interval between the rising edge and the next falling edge of the RD signal. The configuration mode of the HT is called command mode, and its command mode ID is 1 0 0.

The following are the ut1621b mode IDs and the command mode ID: In order to obtain the correct frequency, two additional load capacities C1, C2 are needed. The value of the capacity depends on how accurate the crystal is. We suggest that you can follow the table, which suggests the value of capacities.


Holtek HTB Datasheet

The table illustrates the suggestion value of capacities C1, C2. Command The mode command should be issued before the data or command is transferred. If successive commands have been issued, the command mode ID, namely 1 0 0, can be omitted.

The CS line is used to initialize the serial interface circuit hf1621b to terminate the communication between the host controller and the HT If the CS pin is set to 1, the data and command issued between the host controller and the HT are first disabled and then initialized. It is recommended that the host controller should read in the data from the DATA line between the rising edge of the RD line and the falling edge of the next RD line.

Yes Yes Yes Yes X: Power on reset default All the bold forms, namely 1 1 0, 1 0 1, and 1 0 0, are mode commands. Of these, 1 0 0 indicates the command mode ID. Holfek successive commands have been issued, the command mode ID except for nt1621b first command will be omitted. Calculation of the frequency is based on the system frequency sources as stated above.

It is recommended that the host controller should initialize the HT after power on reset, for power on reset may fail, which in turn leads to the malfunctioning of the HT As this information may be updated at regular intervals users are reminded to consult the Holtek website http: Dimensions in mm Min. Taipei Sales Office 4F-2, No. The information appearing in this Data Sheet is believed to be accurate at the time of publication.

However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise.

Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http: