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Holtek HT98R068-1 Manual

Two-way radio otp mcu
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HT98R068-1 Two-way Radio OTP MCU
D/N: AN0305E
Introduction
The Holtek HT98R068-1 is an ASSP OTP (One-Time Programmable) MCU specifically
designed for two-way radio communication applications. The internal in-band tone/sub-tone
processor supports functions, such as emphasis/de-emphasis, CTCSS/DCS encoder/
decoder, DTMF encoder/decoder, scramble/descramble, VOX...etc., transmitted to the
other port by a radio frequency carrier. Using the code to mark the product extended series,
but it's still avalible in this text such as the HT98R068-1.
Operating Principles
Sub-tone
 CTCSS encode/decode
 DCS encode/decode
In-band tone processor
 DTMF encode/decode
 Selective call tone (EEA standard)
 In band tone(user define)
Other signals
 DCS turn-off tone
Advanced audio processor
 Scrambling
 Companding
 Emphasis/De-emphasis
 Digital filter: 12.5k / 25k / HPF(300) filter
In-band signal level adjustment function
Voice Control(VOX)
MIC AGC
HT98R068-1 Two-way Radio OTP MCU
1

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Summary of Contents for Holtek HT98R068-1

  • Page 1 HT98R068-1 Two-way Radio OTP MCU D/N: AN0305E Introduction The Holtek HT98R068-1 is an ASSP OTP (One-Time Programmable) MCU specifically designed for two-way radio communication applications. The internal in-band tone/sub-tone processor supports functions, such as emphasis/de-emphasis, CTCSS/DCS encoder/ decoder, DTMF encoder/decoder, scramble/descramble, VOX…etc., transmitted to the other port by a radio frequency carrier.

  • Page 2: Block Diagram

    HT98R068-1 Two-way Radio OTP MCU Block Diagram Hardware Block Function Decription  Audio processor unit: A signal process unit, responsible for the audio and signal processing.  Input unit: The input source selection including MIC OPA, multiplexer and PGA. Multiplexer provides selectable audio and modulation signal input such as MICO, AUX, BEEP1 and DEMI.

  • Page 3: Application Circuit

    HT98R068-1 Two-way Radio OTP MCU Application Circuit The application circuit is divided into three main parts.  Clock/PLL circuit: Y1, R7, C16 and C17 are from the PLL external clock source where Y1 is a 32,768 KHz crystal to lock the PLL so as to the set frequency. R6, C14 and C15 are the PLL filter circuits.
  • Page 4 HT98R068-1 Two-way Radio OTP MCU System Clock Switches In the system setup preliminary stage, the operating frequency controlled by two groups of registers, CTRL2 [7-5, 3-0] and CTRL0 [0] is firstly selected. The description is as follows: System Control Register 2 (CTRL2)
  • Page 5 HT98R068-1 Two-way Radio OTP MCU PLL Control Flow - for MCU Flow description: <Set … PLL>: Setup the PLL divider and PLL enable. <Delay10ms>: Delay 10ms which is to wait the PLL to stabilise. <CLKMOD=0>: Set the MCU to be in the PLL mode.
  • Page 6 HT98R068-1 Two-way Radio OTP MCU Audio Processor Reset Flow Flow description: <CTRL2 [4]>: This is the audio processor reset bit. The correct reset sequence is 1  0  1, with two nope instructions in between. <Delay>: This is the audio processor initial time. Any SPI data transmitted during this period may be overwritten by the audio processor and become invalid , which may waste 250ms~300ms.
  • Page 7 HT98R068-1 Two-way Radio OTP MCU SPI Command The audio processor uses the SPI interface as the communication interface with two methods of communicating through the internal (SPICR [7] =1) SPI circuit or the external (SPICR [7] =0) pin-shared I/Os (the following unit will describe). The internal communication can control the...
  • Page 8 HT98R068-1 Two-way Radio OTP MCU SPI Application Example Program The source codes are attached in the HT98R068-1_AppInc.inc file where the SPI application section contains:  SPI command Macro = SPITX (macro)  SPI Write = Procedure_SPI_Tx (procedure)  SPI Read = Procedure_SPI_Rx (procedure) ...

  • Page 9: Cli Command

    HT98R068-1 Two-way Radio OTP MCU  Read 1Eh Flow Flow description: <91E00>: Read the 1Eh register. A data response will be sent to 1Eh after this command is transmitted. CLI Command This interface protocol is different from the I/O command. For the write mode it must contain three bytes of 20-bit SPI data and two for the read mode.
  • Page 10 HT98R068-1 Two-way Radio OTP MCU Ex: Write FFFFh (with MOD and SMOD outputs at the maximum modulation) to the CLI register "04CBh" and then read this register.  Write 04CBh Flow Flow description: <14082>: The CLI writeS ID code. To execute a write operation with the CLI Command, it is necessary to execute this command first.

  • Page 11: External Control

    HT98R068-1 Two-way Radio OTP MCU External Control For different audio processing control requirements, in addition to the internal MCU connections, external SPI control is also supported. However, before using the external control, some relevant initialisation must be executed which includes the PLL, reset and SPI path.
  • Page 12 HT98R068-1 Two-way Radio OTP MCU  Use External Control Flow Flow description: <PLL setting>: Enable and set the PLL. <Audio processor>: Reset the audio processor. <Control signal status>: Check the control signal status and select the SPI path to be external or internal.
  • Page 13 HT98R068-1 Two-way Radio OTP MCU IDLE M ode When the audio processor is not processing data, entering this mode can save power, however the quantity depends on the actual practical situation. The device provides many ways to enter the idle mode (see to the datasheet). Here we use the simplest method.
  • Page 14 HT98R068-1 Two-way Radio OTP MCU TX Mode Entering the TX mode depens on the input data trigger, such as pressing PTT, audio signal (VOX)…etc.The mode switches, input source selection, circuit disabling etc will be generally executed in this mode. As for the audio buffer input source, it is recommended to switch to bias voltage to reduce noise, or disable the buffer (I/O CMD-1Eh [3]), or even choose both.
  • Page 15 HT98R068-1 Two-way Radio OTP MCU RX Mode This mode is mainly applied for in-band signal demodulation. Although it is acceptable to wait for the RF signal in this mode, it is recommended that the MCU should verify the RSSI (Receive signal strength indicator) signal before switching the input source to the DEMOD path and then enable the audio processor for management.
  • Page 16 HT98R068-1 Two-way Radio OTP MCU Audio Processor IRQ When an audio process event occurs, the audio processor will use this signal as an interrupt request, during which time the master should send a SPI signal to read the 20-bit data, transmitting 100h as the first 12 bits data with the last data corresponding to the I/O CMD-23h, the last byte data bit will generate an interrupt if there is a status changing event (0 ...
  • Page 17 HT98R068-1 Two-way Radio OTP MCU Step 2: Rx AUP ISR. Step 3: Rx 23h detection flow. Flow description (1): <82248>: Set the interrupt enabled selection. Select the CTCSS interrupt, enable the interrupt source. Flow description (2): <Is received 10008>: Confirm this interrupt signal is CTCSS event.
  • Page 18 HT98R068-1 Two-way Radio OTP MCU Audio Processor Status Reset When decoding normally, the audio processor processes depending on the signal data code, frequency and amplitude. Its status (I/O CMD-23h, 30h) will change if the communication flow meets with that RF ok  signal ok  signal fail  RF fail. When the audio status changes by a sequence 0 ...
  • Page 19 HT98R068-1 Two-way Radio OTP MCU Selective Call Setting It’s a sine wave frequency anolog signal, has 16 groups of signals. It meets with the standard international specification (EIA, EEA, CCIR, ZVEI 1, ZVEI 2…etc), also, the user can define the frequency channel to applicate flexibly. It can be achieved from 300Hz to 3000Hz.
  • Page 20 HT98R068-1 Two-way Radio OTP MCU Ex: RX mode, Input = DEMOD, Output =null, Non sub-tone.  Set Selective Call RX Mode Flow Flow description: <RSSI OK>: Acknowledge the RF signal is OK. <81EC3>: Enable the PGA circuit, PGA on – enable the input source PGA.

  • Page 21: Dtmf Setting

    HT98R068-1 Two-way Radio OTP MCU DTMF Setting DTMF is a dual tone multiple frequency anolog signal, which includes high frequency tone and low frequency tone. There are 16 groups signals (0~D), common in telephone system dialing or keypad tone. Set I/O CMD-11h [4-2] = b’100. Select the TX encode channel by using the I/O CMD-2Dh [3-0] bits and select the frequencies in the list.
  • Page 22 HT98R068-1 Two-way Radio OTP MCU Ex: RX mode, Input = DEMOD, Output = null, Non sub-tone.  Set the DTMF RX Mode Flow Flow description: <RSSI OK>: Acknowledge the RF signal is OK. <81EC3>: Enable the PGA circuit, PGA on – enable the input source PGA.
  • Page 23 HT98R068-1 Two-way Radio OTP MCU Sub-tone Function For the open systems such as walkie-talkies, under conditions of limited frequency channels, a sub-tone method can be applied to increase the same frequency channel numbers and to receive the required signals. Users at the receiving port should select the correct sub-tone type and channel so as to decode the data properly and reduce unnecessary signals.
  • Page 24 HT98R068-1 Two-way Radio OTP MCU Event 2 Control - 31h Address En_CTC En_CTC Name — — — — — — Rx_Anti-tone Tx_Anti-tone Event 2 Control Register Event 2 Status - 30h Address CTC Anti- Name — — — — —...
  • Page 25 HT98R068-1 Two-way Radio OTP MCU Ex: RX mode, Input = DEMOD, Output = AUDO (sources = DAC1), Sub-tone = CTCSS, CTCSS tone = 01h  CTCSS RX Mode Setup Flow Flow description: <RSSI OK>: Confirm the RF signal is OK.
  • Page 26 HT98R068-1 Two-way Radio OTP MCU DCS Setting DCS is a data waveform formed by a digital carrier signals using “0” and “1” data. The 23-bit data signal includes the checksum and data codes. It provides a choice of 83x2 (reverse codes included) standard channels and one user-defined channel. Set this function by using I/O CMD-11h[1-0] = b’01.
  • Page 27 HT98R068-1 Two-way Radio OTP MCU Ex: TX mode, Input = AUX, Output = MOD & SMOD, Sub-tone = DCS, DCS tone = 01h  DCS TX Mode Setup Flow (1)Tx DCS Signal (2) Transmit an off_tone signal at the end of the signal Flow description (1): <82B01>: Setup the sub-tone channel by selecting the first DCS channel group.
  • Page 28 HT98R068-1 Two-way Radio OTP MCU * * * After the DCS signal is transmitted * * * Flow description (2): <82B7F>: Select the OFF-tone to produce 134Hz signals. <81101>: Return to the idle mode. Complete the DCS and return to the standby status.
  • Page 29 HT98R068-1 Two-way Radio OTP MCU (3) Enable and output the Audio_out signal Flow description (1): <RSSI OK>: Confirm the RF signal is OK. <81EC3>: Enable the PGA circuit, PGA on - enable the PGA input source. <81B33>: Select the PGA and Audio input source paths. Select the PGA input source to be DEMOD and audio out to be DAC common-mode bias voltage to reduce noise.
  • Page 30 HT98R068-1 Two-way Radio OTP MCU Audio Advanced Function The device provides multiple audio processors, including scrambler, compandor, emphasis, HPF, LPF…etc. for a wide range of applications. The function switches are located in I/O CMD-2Ch [7-2]. As the audio processor operating frequencies are different, there are some restrictions in enabling the function groups and for using the TX/RX.
  • Page 31 HT98R068-1 Two-way Radio OTP MCU Audio – Pre-emphasis/de-emphasis Funtction Set The Emphasis function is used to modulate the high/low frequencies of the power spectrum so as to obtain a more average power spectrum density and a better S/N ratio. The high frequency power spectrum of a typical signal tends to reduce while noise will increase rapidly as the frequency rises.
  • Page 32 HT98R068-1 Two-way Radio OTP MCU Audio – Scrambler/De-scrambler Function Setting Scrambling implements reversion signal processing which is an encryption method for the transmitted signals. In the TX mode, signals transmitted through a scrambler will become meaningless and impossible to use. Likewise, when in the RX mode, after the descrambler is used, the scrambled signals will be returned back to their original signals.
  • Page 33 HT98R068-1 Two-way Radio OTP MCU  Change Scrambling Code Inversion Frequency (3200Hz) Flow Flow description: <82C00>: Setup data: 00h. 2Ch [7] = 0 disable the scrambler. <14082>: The CLI wrote ID code. To execute a write operation with the CLI Command, it is necessary to execute this command first.
  • Page 34 HT98R068-1 Two-way Radio OTP MCU Audio – Compandor Function Setting Companding is applied to lower the dynamic range by compressing or expanding the signals. Dynamic range: 60dB, output 30dB, value = 0.5 (subject: MIC in). In a radio transmission process, the RF signals will include noise after reception. Therefore, before the signals are transmitted, the data is compressed by a certain setup ratio.
  • Page 35 HT98R068-1 Two-way Radio OTP MCU In-band Signal Level Adjustment Function The output modulation differs between different system applications. The device provides multi-level modulating settings for different paths and also provides a mixer. The modulation diagram and description are as follows: Modulation Path Block Diagram ...
  • Page 36 HT98R068-1 Two-way Radio OTP MCU  Sub-audio Path Modulating Flow Flow description: <14082>: The CLI wrote ID code. <104CB>: Select the register: 04CB <100FF>: Setup data: 00FFh. VR2 = FFh enables the maximum VR2 level. <Is reply 14000>: The audio processor writes an acknowledge reply.
  • Page 37 HT98R068-1 Two-way Radio OTP MCU Voice Control Function -- VOX The VOX function is often applied in some special applications. From the VOX high level threshold (CLI CMD-04CD) and low level threshold (CLI CMD-04CE) which are related to the MIC voice volume, the input source can be determined whether it is above the threshold (I/O CMD-29[1-0]=02h) or below the threshold (I/O CMD-29[1-0]=01h).
  • Page 38 HT98R068-1 Two-way Radio OTP MCU (2) VOX Signal Status Detection Flow description (1): <81EC7>: Enable the MIC and PGA circuits. MIC on–enable the microphone circuit, PGA on–enable the PGA input source. <81B10>: Select the PGA and Audio input source paths. Select the PGA input source to be MIC and the audio out to be DAC common-mode bias voltage to reduce the noise.
  • Page 39 HT98R068-1 Two-way Radio OTP MCU Auto Gain Control -- AGC The audio input magnitude to microphones usually varies influencing the quality of the audio output. This problem is usually resolved by the addition of an AGC circuit which requires less circuit space but incurs a cost increase. This device includes an internal...

  • Page 40: Parameter Setting

    For details, see the HT98R068-1_AppProgNote_Vxx.pdf. Tool Development Considerations  Use the development tool specifically for the HT98R068-1. Real ICE: MEV (Lot No.:M1001C) DEV (Lot No.: D1044A) or the update version).  To meet with the stabilish requirement, it’s recommended that be used by connecting with power externally to provide correct detection voltage (See e-ICE manual).
  • Page 41 HT98R068-1 Two-way Radio OTP MCU ICE pin assignment of the 64LQFP real chip: Real Real Real Chip Real Chip Real Real Chip Real Chip Real Chip Chip Chip Pin Name Pin Name Chip Pin Pin Name Pin Name PA7/RESB 27/28/29...
  • Page 42 HT98R068-1 Two-way Radio OTP MCU ICE pin assignment of the 48LQFP real chip: Real Real Real Real Real Real Chip Real Chip Real Chip Chip Chip Chip Chip Chip Pin Name Pin Name Pin Name Pin Name PA7/RESB XOUT PLLC...
  • Page 43 HT98R068-1 Two-way Radio OTP MCU Appendix In the different functional groups, the audio processor system clock speed table. Sub-audio Audio Scrambler Compandor Emphasis _Audo ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ None ˇ ˇ ˇ...
  • Page 44 HT98R068-1 Two-way Radio OTP MCU Sub-audio Audio Scrambler Compandor Emphasis Fsys_Audo ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ None ˇ ˇ ˇ ˇ ˇ ˇ ˇ None ˇ ˇ ˇ ˇ ˇ ˇ ˇ ˇ...

This manual is also suitable for:

An0305e