78m6618-imr/f/p Maxim Integrated Products, Inc., 78m6618-imr/f/p Datasheet - Page 10

• Manufacturer Part Number: 78m6618-imr/f/p
• Description: Octal Power And Energy Measurement Ic
• Manufacturer: Maxim Integrated Products, Inc.

78M6618 Data Sheet
1.11 PLL and Internal Clock Generation
Timing for the device is derived from the 32.768 kHz crystal oscillator output. The PLL and on-chip timing
functions provide several clocks which include:
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These internal clocks can be adjusted for various programmable rates which affect device functionality.
See the 78M6618 Programmer’s Reference Manual for more information regarding the programmability
of the 78M6618 PLL and internal clock generation modules.
1.12 Real-Time Clock (RTC)
The RTC circuit is driven directly by the crystal oscillator. The RTC consists of a counter chain and output
registers. The counter chain consists of registers for seconds, minutes, hours, day of week, day of
month, month, and year (including leap years). See the 78M6618 Programmer’s Reference Manual for
more information regarding the use of the 78M6618 RTC.
1.13 Hardware Watchdog Timer
In addition to the basic watchdog timer included in the 80515 MPU, an independent, robust, fixed-
duration, watchdog timer (WDT) is included in the device. It uses the crystal oscillator as its time base
and must be refreshed by the MPU firmware at least every 1.5 seconds. When not refreshed on time the
WDT overflows, and the part is reset as if the RESET pin were pulled high, except that the IORAM bits
will be maintained and a Watchdog timer expired flag will be set. 4096 oscillator cycles (or 125 ms) after
the WDT overflow, the MPU will be re-launched from program address 0x0000. The WDT can be
disabled by tying the V1 pin to within 10mV of V3P3. See the 78M6618 Programmer’s Reference Manual
for more information regarding the use of the 78M6618 Hardware Watchdog Timer.
1.14 Temperature Sensor
The device includes an on-chip temperature sensor for determining the temperature of the bandgap re-
ference. The primary use of the temperature data is to determine the magnitude of compensation required
to offset the thermal drift in the system. See the 78M6618 Programmer’s Reference Manual for more
information regarding the use of the 78M6618 Temperature Sensor.
1.15 General Purpose Digital I/O
The 78M6618 includes up to 19 pins of general-purpose digital I/O. When configured as inputs, these
pins are 5V compatible (no current-limiting resistors are needed).
inputs until they are configured for the desired direction under MPU control. The Digital I/O pins can be
categorized as follows:
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The MPU clock (CKMPU)
The emulator clock (2 x CKMPU)
The clock for the CE (CKCE)
The delta-sigma ADC and FIR clock(CKADC, CKFIR)
DIO1/OPT_RX, DIO2/OPT_TX
DIO3
DIO4/SEG24
DIO13/SEG33 -- DIO19/SEG39
DIO43/SEG63
-- DIO11/SEG31
(2 pins) UART/DIO pin
(1 pin ) Dedicated DIO pin
(8 pins) LCD/DIO pins
(7 pins) LCD/DIO pins
(1 pin ) LCD/DIO pin
On reset or power-up, all DIO pins are
DS_6618_005
Rev. 1.3