Basic Information Functional Description Application Description Points to Note Others

Basic Information

Question 1

How do I change the shared pin locations of PWM0/PWM1/PWM2/TMR0/TMR1/INT0/INT1/PFD in the HT56R2x?

Answer

The HT56R2x MCU can setup the pin-shared I/O of those functions by programming the PINMAP register. Details are listed as follows.


Question 2

What is the accuracy of the 12-bit A/D? What is the sampling time? How long will it take to implement a conversion?

Answer

The accuracy of the 12-bit A/D is 10 bits. The sampling time is four tAD. The conversion time is 16 tAD where each tAD has a minimum value of 0.5us.

Question 3

Compared with the HT56R6x/6xx, what are the special features of the HT53R2x?

Answer

The biggest differences between the HT56R2x and the HT56R6x/6xx are:

  1. The HT56R2x provides a single 12-bit DAC audio output channel while the HT56R6x/6xx does not.
  2. The HT56R2x contains four SCOM outputs max. with I/Os providing 1/2 bias LCD driving capability. The HT56R6x/6xx contains a complete LCD drive module with both R and C type LCD drive capability.
  3. The HT56R2x includes a high accuracy internal RC oscillator with 4MHz/8 MHz/12MHz frequencies while the HT56R6x/6xx has no internal RC oscillator frequency options.

Functional Description

Question 1

What clock modes do the TinyPower series MCU offer?

Answer

The TinyPower series MCU provides a dual clock mode. Here a choice of high speed clock fM and low speed clock fSL can be selected from different clock sources via the configuration options. The high speed clock fM can be set from the OSC option as an external crystal, external RC, external clock or internal RC, while the low speed clock fSL can be setup as 32K RC or 23768 XTAL through the fSL clock select option. In the high speed clock mode, selected by the application program, the system clock is fM, while in the low speed clock mode, the system clock can be the source clock, fSL or fM, divided by 2~64, selected by the application program.

Application Description

　

Question 1

What is SCOM for in the HT56R2x? How is it used and how many LCD pixels does it support?

Answer

The HT56R2x series MCU includes a 1/2 bias LCD drive capability. The SCOM0~3 outputs are controlled using the LCDC register. When the LCDEN and COMxEN bit are 1, the corresponding pin shared by SCOMx and I/O will output a VDD/2 voltage level. Together with the SEG output simulations on other I/O pins, a 1/2 bias LCD drive capability can be implemented easily up to a maximum of 4 x46 pixels.

Question 2

How many operation modes do the HT56R2x series MCU provide? How do I switch between them?

Answer

The HT56R2x series MCU offers five different operation modes, namely the Normal mode, Slow mode 0, Slow mode 1, Idle Mode, and Sleep Mode, all of which can be setup through the HLCLK and IDLEN bits in the CLKMOD register combined with the HALT instruction. When HLCLK=1, the system will be in the Normal Mode, and if 0 will be in the Slow Mode. When IDLEN=1 and the HALT instruction is executed, the system will be in the Idle Mode. When IDLEN=0 and the HALT instruction is executed the system will be in the Sleep Mode. Refer to the datasheet for further mode switching information.

Question 3

How does the HT56R2x generate a 3.3V SPI signal?

Answer

The HT56R2x provides a 3.3V SIP pin setup using a configuration options to communicate with other 3.3V low voltage components without using a voltage converter. To execute this function, enable the VDDIO option to make PA4 the 3.3V voltage input port, and then decide from the configuration options if the PA5, PA6, PA7 and PE0 (or PD2) are using VDDIO or VDD. If VDDIO is selected, the corresponding pins will be input lines for 3.3V voltage data.

Question 4

How can I implement Voice applications in the HT56R2x?

Answer

The HT56R2x provides a 12-bit DAC to implement voice outputs. To implement a voice output function, the voice data should be stored in the external Flash memory. The HT56R2x is able to read data via its SPI interface and write into to the DAH/DAL resisters. Voice outputs are controlled using the DACTRL register. When DACEN=1, the 12-bit voice data written to the DAH and DAL will be converted automatically by the DAC and the corresponding simulated value will be output on the AUD pin. DAH stores high 8-bit voice data while the DAL 4~7 stores the low 4-bit voice data. DACTRL5~7 can also setup the volume control. For details refer to the datasheet.

Points to Note

　

Question 1

What is the internal equivalent circuit of the 12-bit A/D? What is the input resistance and capacitance?

Answer

The equivalent circuit of the ADC input is shown as follows.

ADC samples should only be taken after the VCAP has stabilized so as to ensure the accuracy of the conversion output.
RC Time constant= TRC = (Rs+Rswitch) * Csample (ignore the Cpin effect) Stabilization to 12 bits takes 8 ~ 9 TRC. However the sampling time of Holtek’s ADC is TADCLK, so TRC *8 = (Rs+1.5K)*47pF*8 < 3.5*
TADCLK When TADCLK =500ns ? Rs < 3.15K If the application circuit does not meet the above conditions, it is recommended to add a buffer to the input port or slow down the conversion speed.

Question 2

Does the HT56R2x MCU series share the same ICE tools?

Answer

The HT56R2x series uses Holtek’s latest development tools known as the e-ICE which have the special features of small size and being easy to use. Users can implement HT56R22/23/24/25/26 simulations using the same ICE.

Question 3

How do the HT56R2x series MCU tools support voice application development?

Answer

The HT56R2x series tools provide overall voice development requirements for users to implement their applications. The emulator is equipped with a Flash memory to store voice data and an output pin for the speaker. The IDE-3000 v7.1 also contains special tools for voice data editing and download simulation. The program setting is the same as with the MCU. When DACEN=1, the 12-bit voice data written to the DAH/DAL will be converted automatically through the DAC and the voice simulation value will be output on the AUD pin. For further operating methods refer to the voice description of the development system.

Question 4

When using the HIRC, if the I/O pin which is shared with OSC1 is to be used as an AC zero crossing detector, will there be any influence on the HIRC oscillation frequency? If yes, which MCUs will be affected and how can this problem be resolved??

Answer

If the HIRC is used and if the I/O pin which is shared with OSC1 is used as an AC zero crossing detector pin, the HIRC oscillation frequency will be influenced.
The affected MCUs are:
All MCUs whose I/O pin is pin-shared with OSC1 (including the enhanced OTP type MCU and Flash type MCU etc.)
How to resolve this issue:
1. Avoid using the I/O pin that is shared with OSC1 as AC zero crossing detector pin.
2. If the problem can still not be resolved, add external circuitry to ensure that the voltage applied on the OSC1 pin remains withing the range of VDD and VSS.