HT812D0 2.8 Second LOG-PCM Speech Features • • • • • • • • • • • • Operating voltage: 2.4V~5.0V Directly drives an external transistor Low standby current (1µA Typ. for VDD=3V) Minimal external components 124 words table ROM for key functions Programmable silence length and end-pulse width (minimal end-pulse width is 330µs at a 6kHz sampling rate) 2.8-second voice capacity Controllable volume FLAG1 options: – End-pulse output – 3Hz flash – 6Hz flash – Voice output indication – Busy output FLAG2 options: – 3Hz flash – 6Hz flash – Busy output • Four keys Key options: – Stop key: KEY4 – Random (only for KEY1) – Sequential (only for KEY1) – Repeat (for all KEYs, under retriggerable condition) – Key debounce time (for all KEYs): 700µs, 22ms, 45ms, 180ms (based on a sampling rate of approximately 6kHz) – One shot (for all KEYs) – Level-trigger – Pull-high resistance (for all KEYs) Section options: – Retriggerable – Non-retriggerable Applications • • • • • Toys Alarm clocks Public address system Alert & warning system Sound effect generators General Description The customer’s voice sources are recorded section by section into an internal mask ROM. The sectional playback arrangement instructions of each key are stored in the table ROM. The key features are also programmable. With such a flexible structure, the HT812D0 is excellent for versatile voice applications. The HT812D0 is a single chip LOG-PCM voice synthesizer LSI with 2.8-second voice capacity at 6kHz sampling rate. The chip when triggered drives a speaker through an external transistor with a current switch D/A converter output. Negligible current will be consumed in the standby state. The HT812D0 provides four key inputs and two programmable FLAG outputs. With a 2.4V~5.0V power supply, a complete synthesized voice playback system can be easily built with very few external components. 1 5th May ’98 HT812D0 Pin Assignment Block Diagram Unit: µm Pad Assignment Pad No. X Y 1 2 3 4 5 6 7 8 9 10 11 –919.00 –1007.00 –226.99 61.70 515.20 821.90 1006.90 957.00 894.20 –291.90 –532.50 480.30 –530.30 –480.30 –480.30 –480.30 –480.30 –530.30 289.10 480.30 480.30 480.30 Chip size: 2270 × 1380 (µm)2 * The IC substrate should be connected to VSS in the PCB layout artwork. Pin Description Pin No. Pin Name I/O Internal Connection 1 OSC1 I — 2 FLAG1 O NMOS Open Drain 3 VSS I — 4 FLAG2 O NMOS Open Drain Description Oscillator input pin 3Hz/6Hz flash output, busy output, end-pulse or voice output indication (by mask option). Open drain, active low output Negative power supply (GND) 3Hz/6Hz flash output or busy output (by mask option), open drain, active low output 2 5th May ’98 HT812D0 Pin Name I/O Internal Connection Description 5~8 KEY1~ KEY4 I Pull-High Trigger key, active low. Key features like debounce time, pull-high resistance and repeat can be selected by mask option. 9~13 NC — — No connection 14 VDD I — Positive power supply 15 AUD O PMOS Open Drain 16 OSC2 O — Pin No. Voice output for driving an external transistor Oscillator output pin Absolute Maximum Ratings* Supply Voltage ............................... –0.3V to 6V Storage Temperature ............... –50°C to 125°C Input Voltage ............... VSS–0.3V to VDD+0.3V Operating Temperature ............. –20°C to 70°C *Note: These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings” may cause substantial damage to the device. 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. (Ta=25°C) Electrical Characteristics Symbol Parameter Test Conditions VDD Conditions — Min. Typ. Max. Unit 2.4 — 5.0 V — 200 400 µA — 1 3 µA VDD Operating Voltage — IDD Operating Current 3V ISTB Standby Current 3V IO Max. AUD Output Current 3V VOH=0.6V –1.5 –2 — mA IOL FLAG Sink Current 3V VOL=0.3V 1.5 3.0 — mA VIH “H” Input Voltage — — 0.8VDD — VDD V VIL “L” Input Voltage — — 0 — 0.2VDD V fOSC Oscillating Frequency 3V ROSC=570kΩ 60 76 92 kHz No load, fOSC=96kHz — 3 5th May ’98 HT812D0 Functional Description The HT812D0 is a mask ROM type voice synthesizer with 2.8-second voice capacity. A group of pre-recorded voice sections is played upon receipt of key trigger input signals. Two output FLAGs send signals while playing voices. Play function block diagram The 2.8-second voice capacity can be divided into sections of arbitrary length. Notice that the silence length and end-pulse width are not included in the memory. By using HOLTEK’s programming tools, the contents and arrangement of sections, key features and FLAG output are all programmable before device fabrication. Voice ROM The voice ROM is originally designed to continuously record the 2.8-second voice data at about 6kHz sampling rate. A higher sampling rate can generate voices of good playback quality, but will shorten the total recording time. On the other hand, a lower sampling rate will result in longer recording time but sacrifice voice quality. The IC provides four key inputs (KEY1~KEY4). Of the four keys, KEY1 can be optioned as a direct, sequential or random trigger key. KEY4 can be selected as a stop or direct key. The remaining two keys (KEY2, KEY3), are used as direct keys exclusively. The playback time can be significantly extended by making use of coding efficiency, silence playing, section repeating, section cascade, etc. System oscillator The HT812D0 has a built-in RC oscillator which requires only one external resistor for normal applications. The oscillator frequency is typically 96kHz for an external resistor of 530kΩ. The required oscillator frequency may vary with different sampling rates in the process of voice programming. As a result the value of the oscillator resistor may be different for different items. Section Section is the basic element constituting the contents of the voice ROM. During programming, the customer’s voice sources can be divided into as many sections as required. A section can be composed of a voice or an interval of silence. However, the silent length is not counted in the voice ROM. The total number of sections included should be less than 124 due to the space limitation of the function table ROM. The total length of the included sections is limited by the voice ROM. The oscillator is turned on when triggered by a key input. After playing, the oscillator is immediately turned off and the chip goes into the standby state. A section, when triggered by a key input, can be played once, repeatedly or cascaded with other sections, depending on the key function table instructions. 4 5th May ’98 HT812D0 The following are examples of section division: Key function table Sections in the voice ROM are played according to the instructions of the key function table. The function table contains group information and the playing order of sections in the groups. Notice that the total amount of sections included in the groups should be less than 124–the space limitation of the function table ROM. • KEY1 as a direct key Each key is mapped to a group in the function table. If a key is not used, the group mapped to that key is a piece of silence. The following is an example of the function table: In addition, a section can be set as retriggerable or non-retriggerable depending on the code option. • Retriggerable When the currently playing section is set as retriggerable, it will stop immediately upon receipt of other key inputs. Group 1 sec.1 + sec.2 + sec.3 + sec.5 Group 2 sec.3 Group 3 sec.2 + sec.2 + sec.3 + sec.4 Group 4 sec.5 + sec.3 As illustrated on the above table, the voice ROM is composed of 5 sections, and as a whole comprise 11 sections for the function table. If KEY1 is momentarily triggered, section 1, section 2, section 3 and section 5 are played in sequence and then stopped. Triggering KEY2 plays section 3, and so on. • Non-retriggerable When the currently playing section is selected as non-retriggerable, it will keep on playing till the whole section is completed, whether or not there is a key input during voice playing. • KEY1 as a sequential or random key For a key group, some sections can be set as retriggerable and some as non-retriggerable. When a retriggerable section of a key group is playing, any key can be triggered to interrupt its playing. On the other hand, if a non-retriggerable section is playing, any key interrupt is invalid. When KEY1 is optioned as a sequential or random key, KEY1 can include multiple groups (sub-groups) in the function table. However, the remaining 3 keys (KEY2~KEY4) are used as direct keys exclusively and comprise only one group in the function table. An example is shown below: Group Group 1-1 sec.4 + sec.2 The HT812D0 plays groups according to the key input. A group can be made up of one or more sections. When a key is triggered, the corresponding group is played immediately. For example, triggering KEY2 plays group 2, and so on. The same section is allowed to appear in different groups. However, KEY1 can be made up of multiple groups when it is optioned as a sequential or random key. Otherwise, each key is composed of one group only. Group 1-2 sec.1 + sec.3 : : : : Group 1-N sec.2 + sec.3 5 Group 2 sec.2 + sec.3 Group 3 sec.3 + sec.5 Group 4 sec.1 + sec.5 + sec.2 5th May ’98 HT812D0 following ways: As stated on the table, KEY1 can be made up of sub-groups. The corresponding sub-groups is played in sequence each time KEY1 is triggered. ♦ ♦ ♦ ♦ sequential or random retriggerable – minimum key debounce time (≅700µs, fOSC=96kHz) For instance, if sub-group 1-3 is the previous playing group, sub-group 1-5 will start playing after 2 pulses are applied to KEY1, and so on. – – The playing sequence of sequential KEY1 is: Group 1-1 → Group 1-2 → Group 1-3 ..... → Group 1-N (the last group) → Group 1-1 ..... The playing sequence of random KEY1 is: Group 1-3 → Group 1-5 ..... → Group 1-N → Group 1-3 → Group 1-5 ..... That KEY1 functions as a random key is a special case of sequential key, which combines a particular arrangement of sub-group playing sequence. To make easy selection of KEY1 sub-groups, one of KEY2~KEY4 should be programmed as silence. Then this silence key has to be triggered to reset KEY1. By so doing, the playing sub-group of KEY1 is directly specified by the pulse number applied to KEY1 (see Figure 2). Reset of KEY1 playing sequence If a sub-group of KEY1 group is being played and one of the keys from KEY2~KEY4 is triggered, the playing sub-group will be terminated, and the newly triggered key group is played instead. The first sub-group will start playing by retriggering KEY1. In other words, the KEY1 playing sequence is reset whenever a key other than KEY1 is triggered (see Figure 1). • KEY4 as a stop key (by mask option) When KEY4 functions as a stop key, any voice output can be stopped by pressing KEY4. • KEY1~KEY3 as a repeat key KEY1~KEY3 all function as repeat key if one of the three keys is set as a repeat key. In other words, once the mode of one of KEY1~KEY3 is determined, the remaining two keys are set accordingly. Sub-group selection When KEY1 is triggered with pulses, the desired sub-group can be selected by controlling its corresponding pulse number. As a repeat key, the sections included can be played sequentially and repeatedly till other trigger is applied. KEY4 functions as a stop key when KEY1~KEY3 are set as repeat keys. The features of KEY1 have to be set in the Figure 1 Reset of KEY1 playing sequence Figure 2 KEY1 sub-group selection 6 5th May ’98 HT812D0 When KEY1~KEY3 are set as repeat keys, the key function should be optioned as retriggerable keys. Key features • Key priority When two or more keys are triggered simultaneously, the output voice is decided by the key priority as shown below: FLAG When voices are playing, both FLAG1 and FLAG2 pins are activated to output one of the following signals through code option. KEY1>KEY2>KEY3>KEY4 • Key debounce time FLAG1 can be optioned as one of the following signal outputs: There are four kinds of key-in debounce time to be selected by mask option, namely, 700µs, 22ms, 45ms and 180ms. The key debounce time varies with the value of the system frequency. None, 3Hz flash, Busy, 6Hz flash, Voice indicator, or End-pulse output FLAG2, on the other hand, can be set as one of the following signal outputs: • Pull-high resistance Four kinds of key input pin pull-high resistance can be selected by mask option, namely, 20kΩ, 50kΩ, 100kΩ and 200kΩ. The resistance may vary with VDD, temperatures and the chip itself due to process variations. None, 3Hz flash, 6Hz flash, or Busy output • 3Hz flash When voices are playing, FLAG1 as well as FLAG2 pin outputs a 3Hz signal to drive an LED. The signal is active low, 25% duty. Once the voice output is terminated, FLAG1 and FLAG2 pins become floating outputs. When FLAG1 and FLAG2 pins are optioned as 3Hz output, they will be alternately signaled at a 3Hz rate output. • Trigger mode All of the four keys can be optioned as oneshot trigger mode or level-trigger mode. ♦ One shot When one of the four keys (KEY1~KEY4) is pressed and held down, the group corresponding to that held key will play once. The corresponding group will also play once when one of the four keys is pressed momentarily. • 6Hz flash ♦ When voices are playing, the FLAG1 pin outputs a 6Hz signal to drive an LED. The signal is active low, 25% duty. Once the voice output is terminated, the FLAG1 pin becomes a floating output. When the FLAG1 and the FLAG2 pins are optioned as 6Hz output, they will be alternately signaled at a 6Hz rate output. Level trigger When one of the four keys is pressed and held down, the corresponding group will keep playing. Once the pressed key is released, the group will not stop till the included sections are all completed. 7 5th May ’98 HT812D0 • End-pulse output When the voice output is completed, the FLAG1 pin outputs an active low pulse. The pulse width can be programmed depending on the customer’s requirements. FLAG1 and FLAG2 pins are both floating outputs when the chip is in the standby state. • Busy output When a voice group is playing, the outputs of both FLAG1 and FLAG2 are turned low, indicating that the chip is busy. Volume control The function of the volume control can be set by mask option. A code is written in the function table for the purpose of controlling the volume of each section output after the volume control function is chosen. There are two volume options, namely, full range and half range. In addition to the above-stated output signals, FLAG1 can also generate one of the following signals by code option: • Voice indicator output FLAG1 is active low when voices are playing. It is also turned low during a voice section output. FLAG1 becomes a floating output after the silence section output is completed or the voice output is terminated. AUD The AUD pin is a PMOS open drain structure. It outputs voice signals to drive a speaker through an external NPN transistor when the chip is active. However, the AUD pin becomes a floating output when the chip is in the standby state. The 8050 type transistor with hFE≅150 is recommended for an output driver. 8 5th May ’98 HT812D0 Timing Diagram One-key operation • Sequential-retriggerable • Sequential-nonretriggerable • Random-retriggerable • Random-nonretriggerable Note: Group 1-N may be any of the KEY1 groups 9 5th May ’98 HT812D0 Multi-key operation • Retriggerable • Non-retriggerable • Repeat Note: M, N=1:4 10 5th May ’98 HT812D0 Application Circuits General application Parallel application 11 5th May ’98 HT812D0 Cascade or external driving Power-on play (one shot) 12 5th May ’98 HT812D0 Power-on play (continuous) With volume adjustment 13 5th May ’98 HT812D0 Push-pull output To prevent the speaker and driver transistor from damage due to excess power dissipation which results from a high voltage power supply (4.5V~5.5V), the following push-pull output stage is recommended. Coupling to power amplifier 14 5th May ’98 HT812D0 Standard Item List Item Name ROSC Remarks HT812D1 Baby Cry 532kΩ 4 keys HT812D2 Firecracker 370kΩ 4 keys HT812D3 Train Sound (I) 570kΩ 4 keys HT812D4 Crazy Laugh 787kΩ 4 keys HT812D5 Witch Laugh 469kΩ 4 keys HT812D6* Glass Broken — 4 keys HT812D7 Scream Sound 419kΩ 4 keys HT812D8 Racing Car Sound 572kΩ 4 keys HT812D9 Truck Sound 450kΩ 4 keys HT812DD Duck 397kΩ 4 keys HT812DF* Monkey — 4 keys HT812DG Horse 570kΩ 4 keys HT812DH Cat 427kΩ 4 keys HT812DJ Lion 472kΩ 4 keys HT812DK Elephant 363kΩ 4 keys HT812DL Sheep 264kΩ 4 keys — 4 keys HT812DN* Train Sound (II) * Under development 15 5th May ’98