MSP430 Fan Controller
Thursday 27 MAR 2014 Use MSP "G" 2231 for developmemt. Final will use MSP "F"xxxx Set up watchdog ISR w/ 1ms period Temperature read on board chip in watchdog ISR PWM set using two hardware registers Fan at full speed is 633 Hz -->1.5ms period
Fan speed monitor using watchdog timer. Every ~100 cycles look at and reset counter Hardware ISR increments counter on rising edge of Tach Input. At full speed, expect ~63 counts. At Mid speed expect 31 counts.
8 bit. I2C Sets: use register, value both 8 bit I2C Reads: use register, value.
PINS 1.0 Tach input 1.2 PWM output 1.4&1.5 strap (slave addr) 1.6 SCL 1.7 SCD
Temp, 10 bit adc expect .4 deg res. MCLK -- set to 1 MHz SMCLK div 4 --> 250 KHz Watchdog TimerA = SMCLK /8 = 31.25 KHz