August 27, 1998
GENERAL RELEASE SPECIFICATION
SECTION 14
TEMPERATURE SENSOR
The MC68HC05SB7 MCU can measure temperature in two ways: by using the
internal temperature sensor, or by using an external thermistor.
14.1 INTERNAL TEMPERATURE SENSOR
The internal temperature sensor is designed to measure temperature over the
0°C to 70°C range; with its voltage output connected to channel 5 of the Analog
Subsystem (AN5, see Analog Subsystem section).
The temperature sensor is disabled/enabled by the TSEN bit in the Miscellaneous
Control Register at $0B. The TSEN bit also disables/enables the BandGap
reference voltage.
BIT 7
TSEN
0
BIT 6
LVRON
1
BIT 5
BIT 4
SCLK
0
BIT 3
CSSEL
0
BIT 2
TCSEL
0
BIT 1
BIT 0
MCR
R
0
COPON
0
ESVEN SMINLEV
$000B
W
reset:
0
0
Figure 14-1. Miscellaneous Control Register (MCR)
TSEN — Internal Temperature Sensor and BandGap Reference Enable
This read/write bit enables the internal temperature sensor and BandGap refer-
ence. Reset clears TSEN.
1 = Temperature sensor and bandgap reference enabled.
0 = Temperature sensor and bandgap reference disabled.
NOTE
The temperature gradient is typically 2.2mV/°C ±10%.
The internal temperature sensor is a semiconductor type sensor. Due to process
variations, the absolute output voltage at a given temperature will vary from one
device to another. It is the user’s responsibility to measure and calibrate the
temperature sensor output voltage when the MCU is in the target system.
As an option, the temperature sensor voltage at 80°C is available preprogrammed
into the PEPROM. See PEPROM section.
MC68HC05SB7
REV 2.1
TEMPERATURE SENSOR
MOTOROLA
14-1
FREESCALE [ Freescale ]
