GE MAC 1200

GE Medical Systems MAC 1200 V 1.2 Page 15
Information Technologies 227 492 21 Rev F
m 1/O ports
m Real-Time Clock counter register
In addition, the MPC821 contains a JTAG port with test and programming capabilities.
The MPC821 has the following additional power supplies:
ш VDDSYN, filtered from the + 3.3V logic supply, for the clock generation.
m KAPWR, generated from the + 3.3V logic supply, or from a battery when device is off,
used for buffering the RTC Counter Register.
The clock generation for the MPC821 is realized by a quartz oscillator with 32.768KHz.
The system clock CLOCKOUT is adjusted with the internal PLL register. The system
frequency is 25 MHz.
The Watchdog /Reset Generation is implemented separately in an integrated system
monitoring chip. lt has the following functions:
m Power-up reset for the MPC821 when the device is switched on
m Voltage monitoring of the + 3.3V and + 5V, with reset generation
8 Watchdog
EH Switchover to battery supply for patient ECG memory when device is switched off
m Signal for access protection for patient ECG memory when device is switched off
The Reset Configuration defines startup conditions like boot port size and clock
generation source.
Four LEDs indicate the device status in addition:
LED1: active when a HRESET_ occurs
LED2: indicator for the logic supply
LED3, LED4: indicate internal software states
The control register comprises device control signals to switch off the device, control
battery charging and display control signals.
The status register contains information on the device hardware configuration and the
state of the battery charge.
2.3.5 Real time clock
With Software V5.2, two options for the real time clock are supported. The software checks
for an external real time clock chip (X13 on PWA control). This chip is available with Index
G of PWA Control CS Cl and Index F of PWWA Control CS C.
If the external RTC is found, it will be used for the clock function. If not, the internal clock of
the MPC821 will be used. The external RTC is more accurate than the internal one. Both
clocks are buffered by the voltage KAPWR.