Chapter 4 Functional Description
SRAM
The MV64360 integrates 2Mb of general-purpose SRAM. It is accessible from the CPU or any of the other interfaces. It can be used as fast CPU access memory (6 cycles latency) and for off loading DRAM traffic. A typical usage of the SRAM can be a descriptor RAM for the Gigabit Ethernet ports.
General-Purpose Timers/Counters
There are four 32-bit wide timers/counters on the MV64360. Each timer/counter can be selected to operate as a timer or as a counter. The timing reference is based on the MV64360 Tclk input, which is set at 133 MHz. Each timer/counter is capable of generating an interrupt. Refer to the MV64360 Data Sheet, listed in Appendix C, Related Documentation, for additional information and programming details.
Watchdog Timer
The MV64360 internal watchdog timer is a 32-bit count-down counter that can be used to generate a non-maskable interrupt or reset the system in the event of unpredictable software behavior. After the watchdog timer is enabled, it becomes a free running counter that must be serviced periodically to keep it from expiring. Refer to the MV64360 Data Sheet, listed in Appendix C, Related Documentation, for additional information and programming details.
I2O Message Unit
I2O compliant messaging for the MVME6100 board is provided by an I2O messaging unit integrated into the MV64360 system controller. The MV64360 messaging unit includes hardware hooks for message transfers between PCI devices and the CPU. This includes all of the registers required for implementing the I2O messaging, as defined in the Intelligent I/O (I2O) Standard specification. For additional details regarding the I2O messaging unit, refer to the MV64360 Data Sheet, listed in Appendix C, Related Documentation.
Four Channel Independent DMA Controller
The MV64360 incorporates four independent direct memory access (IDMA) engines. Each IDMA engine has the capability to transfer data between any two interfaces. Refer to the MV64360 Data Sheet, listed in Appendix C, Related Documentation, for additional information and programming details.
I2C Serial Interface and Devices
A two-wire serial interface for the MVME6100 board is provided by a master/slave capable I2C serial controller integrated into the MV64360 device. The I2C serial controller provides two basic functions. The first function is to optionally provide MV64360 register initialization following a reset. The MV64360 can be configured (by switch setting) to automatically read data out of a
