Controller Core - GE MAC 1200 Service Manual

Controller Core

2-10
Functional Description: PCB Control CS_CI
The actual core comprises the Motorola Power PC MPC855T, which contains the
following integrated components.

Chipselect logic

DRAM controller

SCC and SMC for RS-232
 SPI interface

I/O ports

Real-time clock counter register
In addition, the MPC855T contains a JTAG port with test and programming
capabilities.
The MPC855T has the following additional power supplies.

VDDSYN, filtered from the +3.3 V logic supply, for the clock generation.

KAPWR, generated from the +3.3 V logic supply or from a battery when device
is off, used for buffering the RTC Counter Register.
The clock generation for the MPC855T is realized by a quartz oscillator with 32.768
KHz. 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. It has the following functions.
 Power-up reset for the MPC855T when the device is switched on.

Voltage monitoring of the +3.3 V and +5 V with reset generation.

Watchdog

Switchover to battery supply for patient ECG memory when device is switched
off.

Signal for access protection for patient ECG memory when device is switched
off.
MAC 1200 resting ECG analysis system
2012250-095
Revision D