Respironics Trilogy 02, Техническая информация, Страница: 43 / 424

P
AGE
4-8
T
RILOGY
S
ERVICE
& T
ECHNICAL
I
NFORMATION
1002735, V
ER
. 05
Wakeup - The wakeup circuit is a result of a unique requirement for the CPU. Approximately 1 to 2 seconds
after the supply voltage reach a stable operating condition the CPU requires a rising edge on the wakeup
signal to boot. To generate this wakeup signal a 555 timer (U9) is used. When power is applied the timer
generates a 100Hz square wave output used as the wakeup signal for the CPU.
SDRAM - The CPU daughter card has a 64MB synchronous dynamic random access memory (SDRAM) (U2).
This memory is controlled by the processor using the built-in SDRAM controller. This memory is used by the
CPU as a “scratch pad”. The SDRAM has a 13-bit address line (2-bit bank select and 11-bit address input line)
and 32-bit data bus operates at 100MHz. The SDRAM is powered by the 3.3VDC supply.
Flash Memory The CPU daughter card has a 32MB nonvolatile, electrically block erasable (Flash)
programmable memory (U3) configured for 16 bit word size. It stores the application code for the CPU. The
flash memory is organized as thirty-two 128KB erase blocks and each block can be individually written and
erased. The flash memory has a 22-bit address and 16-bit data bus. It is powered by 3.3VDC supply.
Ethernet Controller - The CPU daughter card provides a MAC to PHY interface using the Ethernet (non-PCI)
controller (U6). This device is a mixed signal (Analog/Digital) device, that through the use of a 16 bit parallel
interface generates the 4 necessary outputs signals for the 10/100 Mbps IEEE 8023 Ethernet communication.
The PHY interface is a 4B5B/Manchester encoder/decoder. The Ethernet chip is powered by the 3.3VDC
supply and uses an external clock input of 25MHz.
EERPOM - A serial EEPROM (U13) is connected to a SPI peripheral of the Ethernet controller. It is used by the
controller to store default communication information and parameters.
Keypad LED Driver - The CPU uses a keypad led driver (U7) to provide eight additional I/O ports. The driver
also provides higher output current capacity and to act as a possible ESD buffer for front panel LEDs.