CyClone COMPACTPCI-824 user manual Sdram Eeprom, Jtag Emulator Support

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Table 2-7. I2C Device Addresses

Designator	Device	Function	Address
J10	DDR SDRAM	Memory	10100011
	EEPROM SODIMM	Configuration
U13	LM75	Temperature Sensor	1001000x
U1	LM75	Temperature Sensor	1001001x
U16	24C08-LV	Serial EEPROM	1010000x

2.10.1SDRAM 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.

2.10.2Temperature 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.

2.10.3Serial 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.

2.10.4Phase 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.

2.11JTAG 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

2-10	CPCI-824 User’s Manual
	Revision 1.0, January 2006