Topic       : Documentation of the CT60
Author      : Didier MEQUIGNON
Version     : Version 2.00 (December 11, 2010)
Subject     : Documentation
Nodes       : 135
Index Size  : 3664
HCP-Version : 3
Compiled on : Atari
@charset    : atarist
@lang       : 
@default    : 
@help       : 
@options    : -i
@width      : 75
View Ref-File10.5  THERMAL SENSOR                                              CT60

The 68060 contains a Die Temperature Sensor with two external pins
THERM0 & THERM1. The sensor is done with a temperature sensitive
resistor which has a 780 ohms value at 25°C and increases/decreases
by steps of 2.8 ohms per °C unit. By example, a 060 core at 80°C
gives a resistance of 934 ohms between the two THERMx pins.

 Equations : R60 = 780 + 2.8 x (TEMP 25) or TEMP = (R60 - 710) / 2.8 

The CT60 uses a small slow Analog/Digital converter (TI TLV0831) to
obtain a 8-Bit value of the voltage between the THERMs pins.

 The equation is : U60 = (3.34 x R60) / (1000 + R60)  where R60 is
the value of the core sensor resistor; 3.34 is the power supply and
1000 is the value of the resistor connected between the 3.34V and the
positive THERM0/IN+ line.

 TOLERANCES : 

   ∙ Power supply : 3.3V +/- 4% : From 3.168V to 3.432V. Curently, it
     is 3.30 to 3.34.

   ∙ Resistor : 1K +/-1% : From 990 to 1010 Ohms. Curently, it is
     from 995 to 1005 ohms.

The AD converter uses a REF voltage of 1.800 V. With 0 to 0.007 V
between the two pins of the AD converter, the digital result is 0.
With 1.794 to 1.800 V, the result is 255. The value
increases/decreases by steps of 0.007 V.

 The equation is : Data = INT [U60/0.007]. 

At   0°C : Vin+ = 1.387 V  Data = 197  R60=710
At  25°C : Vin+ = 1.464 V  Data = 208  R60=780
At  50°C : Vin+ = 1.535 V  Data = 218  R60=850
At 100°C : Vin+ = 1.662 V  Data = 236  R60=990

 ATTENTION : The varation of the data is not linear !! 

The CPU must access the TLV831 by a basic bit-by-bit protocol. It is
the software responsibility to respect the protocol & timings of the
following chronogram, and assemble the bits.



f   : Clock frequency                         10 to 600 kHz (typical = 250)
tsu : Setup time, CS LOW before CLK goes HIGH 350 ns MIN
tpd : Propagation delay time :
      output data after CLK goes HIGH         500 ns MAX (typical = 200)
twh : Pulse duration, CS HIGH                 220 ns MIN
tconv : Converstion Time (at 250kHz)          32 us

Three registers are present in the SDR60 chip.

The 060 CPU must drive THCS & THCK and read THDA by these registers.

The address $F1000000, $F1800000 & $F1000000 are used respectively
for THCS, THCK & THDA.

THCS (Chip Select)
LONG WRITE at $F1000000   WRITE 0 to CS Rising edge of CS (removed)
LONG WRITE at $F1400000   WRITE 1 to CS Falling edge of CS (active)

THCK (Clock)
LONG WRITE at $F1800000   WRITE 0 to CLK Falling edge of CLK
LONG WRITE at $F1C00000   WRITE 1 to CLK Rising edge of CLK

THDA (Data Output)
LONG READ at $F1000000   READ from DO
                         Value is available on D0 of the CPU data bus.

For an example, see the example in the DIMM EEPROM chapter.