Stensat Controller
The controller is implemented using a modified MIM v2.0 Module (based on the Micro Chip PIC16C73A) and a California Micro CM8870 DTMF decoder for command control. The modified MIM provides the following functionality:
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External watch dog reset |
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Antenna release (by pulsing nichrome wire to melt release line) |
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Morse Code Id |
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AX.25 telemetry |
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Command Processing (from CM8870 DTMF chip) |
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A/D sensor inputs (voltage, current, RSSI, temp) |
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3 Digital sun sensor inputs |
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Set TX power level (Hi/Lo) |
The controller is connected to a Linear Technology LTC694-3.3v Microprocessor Supervisory Circuit that acts as a low voltage cutoff monitor and as a 100ms external watchdog timer to help protect against RAD latchups. The controller uses switching FET's to control the antenna release, TX power level, RX squelch (RSSI) and the main power bus. The controller is located on the bottom internal circuit board.