ADUC847 Analog Devices, ADUC847 Datasheet - Page 70

• Manufacturer Part Number: ADUC847
• Description: Precision Analog Microcontroller: 12MIPS 8052 Flash MCU + 10-Ch 24-Bit ADC + 12-Bit DAC
• Manufacturer: Analog Devices

Specifications of ADUC847

• Mcu Core: 8052
• Mcu Speed (mips): 12
• Sram (bytes): 2304Bytes
• Gpio Pins: 34
• Adc # Channels: 10
• Other: PWM

ADuC845/ADuC847/ADuC848
TIME INTERVAL COUNTER (TIC)
A TIC is provided on-chip for counting longer intervals than
the standard 8051-compatible timers can count. The TIC is
capable of timeout intervals ranging from 1/128 second to 255
hours. Also, this counter is clocked by the external 32.768 kHz
crystal rather than by the core clock, and it can remain active in
power-down mode and time long power-down intervals. This
has obvious applications for remote battery-powered sensors
where regular widely spaced readings are required. Note that
instructions to the TIC SFRs are also clocked at 32.768 kHz, so
sufficient time must be allowed in user code for these instructions
to execute.
Six SFRs are associated with the time interval counter,
TIMECON being its control register. Depending on the
configuration of the IT0 and IT1 bits in TIMECON, the selected
time counter register overflow clocks the interval counter. When
this counter is equal to the time interval value loaded in the
INTVAL SFR, the TII bit (TIMECON.2) is set and generates an
interrupt, if enabled. If the part is in power-down mode, again
with TIC interrupt enabled, the TII bit wakes up the device and
resumes code execution by vectoring directly to the TIC
interrupt service vector address at 0053H. The TIC-related SFRs
are described in Table 45. Note also that the time based SFRs
can be written initially with the current time; the TIC can then
be controlled and accessed by user software. In effect, this
facilitates the implementation of a real-time clock. A basic block
diagram of the TIC is shown in Figure 47.
Rev. B | Page 70 of 108
Because the TIC is clocked directly from a 32 kHz external
crystal on the parts, instructions that access the TIC registers
are also clocked at 32 kHz (not at the core frequency). The user
must ensure that sufficient time is given for these instructions
to execute.
TIME INTERVAL COUNTER INTERRUPT
TCEN
INTERVAL TIMEOUT
32.768kHz EXTERNAL CRYSTAL
HUNDREDTHS COUNTER
SECOND COUNTER
MINUTE COUNTER
Figure 47. TIC Simplified Block Diagram
HOUR COUNTER
PRESCALER
HOUR
8-BIT
HTHSEC
SEC
MIN
INTERVAL COUNTER
INTVAL SFR
EQUAL?
8-BIT
SELECTION
ITS0 ITS1
TIMEBASE
INTERVAL
MUX
TIEN