HARDWARE
2-10
CPCI-824 User’s Manual
Revision 1.0, January 2006
Table 2-7. I
2
C Device Addresses
2.10.1
SDRAM EEPROM
The EEPROM located on the DDR SDRAM module contains identification and configuration infor-
mation. Breeze code will read this information on power-up and will properly configure the
PPC440GX processor to the SDRAM type. No user intervention is required.
2.10.2
Temperature Sensors
The LM75 temperature sensors have overtemperature trip points that will trigger an interrupt when
crossed. The sensors have been placed on the board U1 & U14 and share an interrupt line to the
processor. Polling the two devices will be required to determine which part has triggered the interrupt.
The sensors are placed in interrupt mode by the Breeze initialization code. The default overtemperature
point is 80 degrees Celsius. The sensors can be read for a temperature reading at any time, reading after
an interrupt clears the interrupt. The sensor will not interrupt again until the temperature has dropped
below the hysteresis value (default is 75 degrees Celsius) and risen again passed the trip point. Consult
the LM75 data sheet for more details on programming the temperature sensors.
2.10.3
Serial EEPROM
The first time a CPCI-820 is powered up, initial conditions are read from a serial EEPROM connected
to the I2C bus. The device is read during reset. Initially, the serial EEPROM is disabled and the
processor powers up in a default state. Once the board is programmed and the serial EEPROM is
programmed, then subsequent power ups will use the data stored.
2.10.4
Phase Lock Loop Clock Driver
The PPC440GX memory controller generates a single differential pair memory clock for the DDR
SDRAM devices. The CDCV850 is a low skew, low jitter, zero delay buffer that distributes the differ-
ential clock to the three input pairs of the 200 pin SoDIMM.
2.11
JTAG EMULATOR SUPPORT
The CPCI-824 provides a joint test action group JTAG emulator interface at J27 for XScale compatible
emulators. The JTAG emulator interface connects to the JTAG port of the IOP331 processor and has the
ability to assert a reset to the secondary PCI bus. The JTAG emulator header definition is shown in
Table 2-8
Designator
Device
Function
Address
J10
DDR SDRAM
EEPROM SODIMM
Memory
Configuration
10100011
U13
LM75
Temperature Sensor
1001000x
U1
LM75
Temperature Sensor
1001001x
U16
24C08-LV
Serial EEPROM
1010000x
