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Microcyber HT1200M, Руководство пользователя

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http://www.microcyber-fieldbus.com

HART Modem ASIC | HT1200M | Page

Email | [email protected]

9

ceramic resonator when using the internal oscillator or grounded when using an

external 460.8 kHz clock signal.

OCBIAS: Comparator Bias Current

The current through this output controls the operating parameters of the internal

operational amplifiers and comparators. For normal operation, OCBIAS current is

set to 2.5 uA.

OCD: Carrier Detect Output

This output goes high when a valid input is recognized on IRXA. If the received

signal is greater than the threshold specified on ICDREF for four cycles of the IRXA

signal, the valid input is recognized.

ORXAF: Analog Receive Filter Output

This signal is the square wave output of the receiver high-pass filter.

ORCD: Digital Receive Output (CMOS)

This signal outputs the digital receive data. When the received signal (IRXA) is 1200

Hz, ORXD outputs logic high. When the received signal (IRXA) is 2200 Hz, ORXD

outputs logic low. ORXD is qualified internally with OCD and is logic high when

OCD is low.

OTXA: Analog Transmit Output

This output provides the trapezoidal signal controlled by ITXD. When ITXD is low,

the output frequency is 2200 Hz. When ITXD is high, the output frequency is 1200

Hz. This output is active when INRTS is low and 0.5 VDD when INRTS is high.

OXTL: Oscillator Output

This output from the internal oscillator must be connected to an external 460.8 kHz

clock signal or to a parallel mode 460.8 kHz ceramic resonator when using the

internal oscillator.

TEST(12: 1): Test Pin

These are test pins. For normal operation, tie these signals as per Table1.

VDD: Digital Power

This is the power for the digital modem circuitry.

VDDA: Analog Supply Voltage

This is the power for the analog modem circuitry.

VSS: Ground

This is the analog and digital ground.

Содержание HT1200M

Страница 1: ...MICROCYBER HT1200M User Manual HART Modem ASIC According to HCF_SPEC 54 Version 1 1 Date 07 12...

Страница 2: ...http www microcyber fieldbus com Revision History Version Release Date Detail of Changes 1 1 07 12 22 First release...

Страница 3: ...0M Pin Descriptions 7 List of Figures Figure 1 HT1200M Hart Modem Typical Application 6 Figure 2 a 28Pin PLCC Pinout Package b 32Pin LQFP Pinout Package 6 Figure 3 Reset Timing 8 Figure 4 HT1200M Bloc...

Страница 4: ...ith the SYM20C15 The HT1200M uses Phase Continuous Frequency Shift Keying FSK at 1200 bits per second To conserve power the receive circuits are disabled during transmit operations and vice versa This...

Страница 5: ...ldbus com HART Modem ASIC HT1200M Page Email fang siqi microcyber cn 6 Typical Application Figure 1 HT1200M Hart Modem Typical Application Pin Assignment a b Figure 2 a 28Pin PLCC Pinout Package b 32P...

Страница 6: ...ICDREF input 12 9 Carrier detect reference voltage OCBIAS output 13 10 Comparator bias current TEST10 input 14 11 Connect to Vss VDDA power 15 13 Analog supply voltage IRXA input 16 14 FSK modulated H...

Страница 7: ...holds all the digital logic in Reset During normal operation INRESET should be at VDD INRESET should be held low for a minimum of 10 ns after VDD 2 5 V as shown in Figure 3 INRTS Request To Send Figu...

Страница 8: ...l outputs the digital receive data When the received signal IRXA is 1200 Hz ORXD outputs logic high When the received signal IRXA is 2200 Hz ORXD outputs logic low ORXD is qualified internally with OC...

Страница 9: ...analog receive circuitry band pass filters the received signal for input to the modem and the carrier detect circuitry The oscillator provides the modem with a stable time base using either a simple...

Страница 10: ...cuit produce received serial data at ORXD Maximum demodulator jitter is 12 percent of one bit given input frequencies within HART specifications a clock frequency of 460 8 kHz 1 0 percent and zero inp...

Страница 11: ...unt to 3 33 ms when the received signal is 1200 Hz and to 1 82 ms when the received signal is 2200 Hz ANALOG RECEIVER CIRCUITRY Voltage References The HT1200M requires two voltage references IAREF and...

Страница 12: ...he input impedance of the entire filter is greater than 150 ohm at frequencies below 50 kHz Figure 8 Receive Schematic OSCILLATOR The HT1200M requires a 460 8 kHz clock signal on OXTL This can be prov...

Страница 13: ...0 8 kHz clock as shown in Figure 10 rather than the internal oscillator because of the high cost and low availability of ceramic resonators In addition the HT 1200M consumes less current when an exter...

Страница 14: ...http www microcyber fieldbus com HART Modem ASIC HT1200M Page Email fang siqi microcyber cn 15 Package Information Figure 10 LQFP32...

Страница 15: ...http www microcyber fieldbus com HART Modem ASIC HT1200M Page Email fang siqi microcyber cn 16 Figure 11 PLCC28...

Страница 16: ...ut Voltage Low 2 7 5 5V 0 3 VDD V VIL INRESET INRTS 2 7 3 3V 0 9 1 2 1 4 V VIH Input Voltage 2 7 5 5V 0 7 VDD V VIH INRESET INRTS 2 7 3 3V 1 3 1 8 2 3 V VOL Output Voltage Low IOL 1 8mA 2 7 3 3V 0 4 V...

Страница 17: ...nge 150 0 15 0 025 VDD 0 15 V s kHz V s IRXAC Carrier Detect Receive Filter Input Leakage Current 500 nA OTXA Modulator Output Frequency Mark Logic1 Frequency Space Logic0 Amplitude IAREF1 235V Slop 3...

Страница 18: ...siqi microcyber cn 19 CERAMIC RESONATOR EXTERNAL CLOCK SPECIFICATIONS VDD 2 7V to 5 5V VSS OV TA 40 C to 85 C Parameter Min Typical Max Units Resonator Tolerance 460 8 1 kHz Frequency External Clock...

Страница 19: ...ge Email fang siqi microcyber cn 20 YOUR FIELDBUS EXPERT CONTACT INFORMATION Address 17 8 Wensu Street Hunnan New District Shenyang China Website www microcyber fieldbus com Phone 86 24 31217278 86 24...

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