MART-02: GENERAL PURPOSE MODULE TO RECORD AND TO PLAY-BACK AUDIO MESSAGES Assemble-it-yourself kit 1 mart02.pdf
The MART-02 Module is applicable for multiple recording and playing back audio signals using non-volatile analog memories, types ISD1416 or ISD1420, made by Winbond Electronics Corporation America (WECA). They feature high quality of sound recording, simple design and long storage time without power supply (as much as 100 years). Integrated circuits applied, like most of ISD devices, enable easy way to create various functions without any additional control circuits. These functions including, but not limited to the following: ADDRESSABLE RECORDING OF MESSAGES, ADDRESSABLE LEVEL-ACTIVATED PLAYBACK OF MESSAGES, ADDRESSABLE EDGE-ACTIVATED PLAYBACK OF MESSAGES, OPERATIONAL MODES (ADDRESSLESS) which enable: o message looping (continuous playback), o consecutive record with message separation method, o consecutive record with message linking method, o message cueing. Figure 1 below illustrates a circuit diagram of the MART-02 Module including external components which need to be connected to create the device of its full functionality. P1 1 P5 P6 P16 P7 P17 P8 P18 P9 PLAYBACK1 P15 PLAYBACK2 P14 RECORD P12 C1 1nF P2 R1 47k R2 47k R3 47k 9 8 7 6 5 4 3 2 1 2 3 4 5 6 9 10 23 24 27 26 R4 -R11 8x47k A0 A1 A2 A3 A4 A5 A6 A7 PLAYL PLAYE REC XCLK U1 VCCD VCCA VSSD VSSA SP+ ISD1416 SP- ISD1420 ANAIN ANAOUT RECLED MICREF MIC AGC 28 16 12 13 14 15 20 21 25 18 17 19 R14 470k C7 100nF C2 100nF R13 5,1k C4 100nF C3 4,7uF C5 100nF R18 1k C6 220uF R17 10k R15 1k R16 10k P3 P19 P10 P20 P11 P13 P4 LED + - 4,5-5,5V Speaker 16 Ω Signal from external source Electret microphone MART-02 Fig.1. Circuit diagram of MART-02 Module. 2 mart02.pdf
The kit includes integrated circuit ISD14xx and PC board (without other electronic devices). PC board component layout is shown in Fig.2. Fig.2. Component layout on PC board of MART-02 (Scale 2:1). All applicable control and audio signals are connected to soldering points P1 P20 located in two rows and spaced each other by 0.1 (2.54 mm), enable to solder of 20-pin double-row connector or a wire harness. Microphone leads shall be shielded and as short as possible. PORTS OF All address signals, A0 through A7, and control signals, PLAYE, PLAYL, REC, RECLED and XCLK of ISD devices are of digital nature and may take one of two possible levels: L* or H*. * Voltage of L-level (shortly: L level) means, in case of ISD devices, the voltage of 0 0.8 V with respect to ground. Voltage of H-level (shortly: H level) means, in case of ISD devices, the voltage of 2.4V Vcc with respect to ground, where Vcc the supply voltage. Hereinafter, an alternative notation will be used for specific address or control signal (input/output): signal name = L, signal name = H. 3 mart02.pdf
P1 - power supply +4.5 +5.5 V P2 - input of external clock signal XCLK. Refer to ISD Data Sheets as to how use this signal. If not used, connect this input to electrical ground. P3 - output to external LED to indicate recording (optionally). This output is controlled by signal at RECLED pin of ISD device. During recording (REC = L), LED is on. During playback, RECLED is at first high and when the end of message (EOM) mark is detected, this signal goes low for the period of 12.5 or 15.6 ms. P4 - microphone input (-) P5 - address input A0 P6 - address input A1 P7 - address input A3 P8 - address input A5 P9 - address input A7 P10 - speaker output (+) P11 - input for signal to record from external source P12 - input for REC signal, triggering level-activated recording (recording is started with HL edge and lasts as long as this input is kept low) P13 - microphone input (+) P14 - input for PLAYE signal, triggering edge-activated playback of recorded message (full message is played back by applying a short low pulse; playback is activated by HL edge) P15 - input for PLAYL signal, triggering level-activated playback of recorded message (playback is activated by HL edge and lasts as long as this input is low) P16 - address input A2 P17 - address input A4 P18 - address input A6 P19 - power supply (-) - electric ground P20 - speaker output (-) Note that audio signals at both speaker outputs are at DC voltage of about 1.5 V and are phase shifted each other by 180 o. WARNING: Connection of speaker outputs (P10 and P20) both with each other and with electric ground may cause damage to the integrated circuit. 4 mart02.pdf
DESCRIPTION OF OPERATION A basic operating mode of the Module is the address mode which enables to record and to playback many independent audio signals of maximum total duration and frequency band of: (i) 16 s and 0.15 3.4 khz for ISD1416, or (ii) 20 s and 0.15 2.7 khz for ISD1420, in successive cells of analog memory, divided into 160 addressable rows (identical number of rows in both ICs). This means that maximum 160 independent messages may be recorded, each of duration time 0.1 s or 0.125 s for ISD1416 or ISD1420, respectively. Actual number of messages and their duration depend on address selection within the memory address space. Addressing is made with a binary coding at eight (8) address inputs A0 A7 to the rule specified in Table 1 below. Binary digit 0 is equivalent to the L-level voltage while binary digit 1 to H-level voltage. Note that an address being specified always points out a memory row wherefrom specific operation is started. Further internal addressing of successive memory cells is made without any involvement of the user, via a so called Message Start Pointer (MSP), which is inaccessible from outside. At the start of write/read cycle the MSP pointer is set to the initial value corresponding to the specified address. Longer messages will be automatically loaded into successive memory rows, as necessary, until the process is completed or memory end is reached. Operation may also run without addressing (so called Operational Modes) where the initial address is always equivalent to the beginning of the system memory (00000000). In these modes the states at address inputs are not treat as address, but specify the type of the function being realized. These functions affect then internal addressing within the memory. The system is switched over into operational modes by providing H-level voltage to A6 and A7 address inputs (P18 and P9 ports). Individual modes are activated by applying H-level signals to specific address inputs as specified below: A0 = H - message cueing (for playback only), A1 = H - deleting internal end-of-message (EOM) markers (for record only), A3 = H - message looping during playback, A4 = H - consecutive addressing; retaining current value of MSP when starting specific operation. 5 mart02.pdf
Digital number of memory row Table 1 A7 A6 A5 A4 A3 A2 A1 A0 Start time of operation for ISD1416 [s] Start time of operation for ISD1420 [s] 0 0 0 0 0 0 0 0 0 0,000 0,000 1 0 0 0 0 0 0 0 1 0,100 0,125 2 0 0 0 0 0 0 1 0 0,200 0,250 8 0 0 0 0 1 0 0 0 0,800 1,000 16 0 0 0 1 0 0 0 0 1,600 2,000 32 0 0 1 0 0 0 0 0 3,200 4,000 64 0 1 0 0 0 0 0 0 6,400 8,000 128 1 0 0 0 0 0 0 0 12,800 16,000 158 1 0 0 1 1 1 1 0 15,800 19,750 159 1 0 0 1 1 1 1 1 15,900 19,875 Combinations of operational modes may also be used to effect various functions of the module. All address and control inputs on PC board are biased at the H-level. These inputs may be driven to L-level by applying external signal at L-level, e.g. by connecting to electric ground (current consumption at these inputs may be neglected). At the end of a record or playback cycle, the module automatically enters the power down mode, where current drawn from power supply is greatly reduced (it depends on the states of address and control inputs). The integrated circuit itself, ISD1416 or ISD1420, consumes typically as low as c. 0.5 µa in this mode. Before starting with recording and playing back, external components shall be connected to the ports P1 P20 as shown in Fig.1. These are as follows: - power supply unit (battery, power pack); - electret microphone providing signal voltage c. 20 mvpp; - speaker, 16 Ω; - LED (operating current of c. 7 ma); - push-buttons referred to in the diagram as PLAYBACK1, PLAYBACK2 and RECORD. The diagram does not provide all possible means for controlling ISD14xx devices. In particular, record or playback may be initiated by means of external control signals of specified levels (instead of push-buttons). Furthermore, signals from speaker outputs may be applied to audio amplifier input so as to get higher output power. 6 mart02.pdf
ADDRESSABLE RECORD OF MESSAGES** This function enables to record independent messages under various addresses. The total recording time must not exceed 16 s for ISD1416 or 20 s for ISD1420. Apply address as per Table 1 to the address input A0 to A7 (record shall start from the memory row of this address). Initiate record by applying L-level voltage to the REC input (port P12), e.g. connect P12 with electric ground by means of RECORD push-button. Record message using microphone connected to ports P13 and P4. Record is initiated with HL edge of REC signal and lasts until the end of L-level of this signal (LH edge). At the same time, the end of record is marked out with an internal marker EOM, which is used for play-back. Record terminates also when end of the memory is reached. Apply successive address to the address inputs to record the next message and repeat the operation. Pay attention for the messages do not overlap one another within the address space of the system as it will cause disturbances during playback (overlapped messages will be seen as the single message and the message recorded later on will cancel the previous one within their common portion). Record is indicated by LED, connected to port P3, which is switched on for this operation. Also an audio signal applied to ANA IN input (port P11) from external source, e.g. tape recorder, tuner, generator, sound card of computer, etc can be recorded. The microphone circuit may be then omitted. Record has priority over playback, i.e. record initiated during playback causes playback interruption and record the message at this address. ** Observe the order of specified actions. Especially, the address line voltages shall be stabilised before the signals are applied to the control inputs PLAYL, PLAYE and REC. 7 mart02.pdf
LEVEL-ACTIVATED ADDRESSABLE PLAYBACK OF MESSAGES There are two methods which enable to playback independent messages stored at various addresses. These can be achived by following way: Apply address of the message start to address inputs A0 to A7 (playback shall start from the memory row of specified address). Initiate playback operation by applying L-level voltage to the input PLAYL (port P15), e.g. by connect P15 with electric ground by means of push-button PLAYBACK1. Playback is continued as long as the L-level is kept at this input; and is terminated when the H-level is returned (LH edge) or when end of message or end of memory is reached. EDGE-ACTIVATED ADDRESSABLE OF MESSAGES Apply message address to address inputs. Initiate playback operation by applying, to the input PLAYE (port 14), the triggering pulse of L-level and duration shorter than the time of message to be playback, however not shorter than 300 ns (e.g. temporarily connect P14 with electric ground with the push-button PLAYBACK2). This operation is initiated by HL edge of the pulse. The message is played back in full, i.e. until the EOM marker is encountered. OPERATIONAL MODES (ADDRESSLESS) 1. Message looping This mode enables continuous playing back a single message recorded from the beginning of memory. Apply L-level voltage to all address inputs. Record one message of total duration up to 16 s (ISD 1416) or 20 s (ISD1420) as outlined above. Apply H-level voltage to address inputs A6 and A7, which causes the system to be switched over to operational modes. Apply H-level voltage to address input A3. Start playback operation by level-activated method (PLAYBACK1) or edge-activated method (PLAYBACK1) as outlined above (while keeping the state of address lines unchanged). The message will be repeated: until H-level is re-established at the input PLAYL for the former case, or until disconnecting the power supply of the system for the latter case. 8 mart02.pdf
2. Consecutive recording This mode enables to record many messages one after another with no need to address each of them. There are two methods of such record as outlined below. Consecutive record by message linking method Messages are recorded consecutively from the beginning of memory; they compose an entirety which, when playback, is treated as a single record. Apply H-level voltage to address inputs A1, A4, A6 and A7; the remaining address inputs to be at L-level voltage. Record the first message by applying L-level voltage to the input REC. Terminate the record by returning H-level voltage at this input. While keeping the state of address inputs, use the same method to record the second message and possibly the successive ones. Consecutive record by message separating method Messages are recorded one after the other from the beginning of memory, each successive message having been recorded immediately after the previous one. Messages are independent each other which, in effect, is similar to the addressable record, but in this case the addresses of individual messages are unknown. During playback the messages are not linked. Apply H-level voltage to the address inputs A4, A6 and A7 and L-level voltage to the remaining address inputs. Record consecutive messages as outlined above. 3. Playing back messages which were recorded consecutively Method I normal playback With this method, the pointer MSP is cleared which causes that each new playback operation commences from the memory beginning. a) signal level activation Apply H-level voltage to address inputs A6 and A7 and L-level voltage to the remaining address inputs. Start playback by applying L-level voltage to the input PLAYL. In case of messages recorded with linking method, consecutive messages will be read one after the other as the integral unit as long as the input PLAYL is low or until the end of the last message or the end of memory. In case of messages recorded with separating method, just the first 9 mart02.pdf
message will be played back like for the addressable level-activated playback for the message with the address of 00000000. b) signal edge activation Bias the inputs as in previous case. Start playback by applying the trigger pulse to the input PLAYE. In case of messages recorded with linking method, they all will be played back one after the other as a single message. In case of messages recorded with separating method, just the first message will be played back like for the addressable edge-activated playback for the message with the address of 00000000. Method II consecutive playback With this playing back mode, there is no clearing of the message pointer MSP, so it is possible to memorise current location in memory and to playback its full content. a) signal level activation Apply H-level voltage to the address inputs A4, A6 and A7 and L-level voltage to the remaining address inputs. Start playback by applying L-level voltage to the input PLAYL. Consecutive messages having been recorded with linking method will be played back as an integral unit as long as the input is low or until end of the last message, or end of memory. If playback is stopped and then restarted, playing back will be continued from the point of stoppage. In case of messages having been recorded with separating method, playing back will start from the first message and will be continued until the input PLAYL becomes high or until the end of message. When restarted, playing back will be continued from the point of stoppage until the end of current message or until the point of next stoppage. When repeating this operation, we can play back all messages while we do not know their addresses. b) signal edge activation Bias the inputs as in previous case. Start playback by applying the trigger pulse to the input PLAYE. In case of messages recorded with linking method, they all will be played back one after the other as a single message. In case of messages recorded with separating method, each consecutive trigger pulse will cause that consecutive message will be played back in full. When repeating this operation, we can play back all messages while we do not know their addresses. 10 mart02.pdf
If the Method II is used and we reach the end of memory, the playing back will be stopped and the device is no longer responsive to successive activation. This is because the message pointer MSP has not been cleared so there is no way to go to the beginning of the memory. This status may be left out by momentary disconnecting the power supply or by returning L-level at the address input A4 (switching to the Method I) and restarting the playback. 4. Message cueing This function enables to find out any message (among others being recorded with addressing method or with consecutive recording with message separating) without specifying its address. To use this function we need to know the successive number of the message being searched for. Apply H-level voltage to address inputs A0, A4, A6 and A7 Apply shifting pulses, each at L-level and of duration 300 ns 10 µs to the control input PLAYE; each such pulse causes a jump forward to the next message (with no playing it back) and an indication of the next message. Apply L-level voltage to the input A0 (termination of cueing process). Playback the message pointed out by applying the L-level trigger pulse to the input PLAYE. Consecutive activating pulses will cause successive messages to be playback, while repeated activation of cueing function (by applying H-level to the input A0) will cause the process outlined above to be started from the end of the last message being played back. BASIC TECHNICAL DATA OF Power supply: +4.5 5.5 V. Recording time: 16 s (for ISD1416) or 20 s (for ISD1420). Message retention: 100 years non-volatile message storage without power supply. Maximum frequency of recorded signal: 3.4 khz (for ISD1416) and 2.7 khz (for ISD1420). Acoustic power: 12 mw at speaker resistance of 16 Ω. Recording signal voltage from external source: max. 50 mvpp. Microphone inputs adapted to connect any electret microphone providing output signal max. 20 mvpp. The MART-02 Module enables also many other functions which are derivatives of those outlined above. It is up to user s invention how they will be exercised. 11 mart02.pdf