BIT3 MODEL 607
Adapter with DMA connects a GIO Bus system to a VMEbus system
Bit 3's Model 607 is an easy-to-use, cost effective way to share memory and special purpose boards between a Silicon Graphics GIO bus computer and a VMEbus system. The Model 607 Adaptor provides high-speed data transfers between systems, and requires minimal software support.
Model 607 interconnects the GIO32 or GIO32bis (but not the GIO 64) bus and VMEbus systems at the physical layer. Working at the lowest level, the bus, the Adaptor allows the two systems to share memory; memory appears to and is treated by each system as if it were its own. In addition, a card only available on one bus may be directly controlled by a device on the other bus. For example, an Array Processor board in a VMEbus chassis can be directly controlled by the GIO processor.
The Model 607 Adaptor allows each bus to operate independently. The timing of the GIO bus and VMEbus is linked only when a memory or I/O reference is made to an address on one system that translates to a reference on the other. The integrity of the interface between Adaptor cards is maintained by parity checks on address, control and data lines.
Model 607 supports bi-directional random access bus mastering from either system and also supports 16- / 32-bit data transfers using a built-in DMA Controller. The DMA Controller is a high-speed data mover engine that moves data between GIO system memory and the VMEbus at sustained data transfer rates up to 26 Megabytes per second (M Bytes/sec). It also allows a VMEbus DMA device (such as a disk controller) to DMA through the Adaptor directly into GIO memory at data transfer rates in excess of 12M Bytes/sec. Actual performance rates are dependent on the capabilities of the specific GIO system and the speed of the VMEbus memory.
Other Bit 3 Adaptors, supporting a wide variety of buses, can be used with Model 607 Adaptors to connect multiple computers and systems in star, daisy-chain or modified star/daisy-chain configurations.
COMMUNICATIONS BETWEEN GIO BUS & VMEbus
Model 607 supports two methods of intersystem communications: Memory Mapping and Direct Memory Access (DMA).
Memory Mapping controls random access (PIO transfers) to remote bus RAM, dual-port memory, and remote bus I/O, and provides an easy-to-use, flexible interface with low overhead. When the GIO bus is the transmitting system, it can access up to 4G bytes of memory in the VMEbus system through a window in GIO bus address space. Conversely, if the VMEbus is the transmitting system, it can access all GIO bus memory from a window in VMEbus address space.
Seven Window Mapping Registers are available to steer accesses in 256K segments from GIO address space to VMEbus address space. Likewise, there are 16 Page Mapping Registers available for accesses from VMEbus address space to GIO address space.
Memory Mapping also controls access to dual-port memory. Dual Port RAM is an optional card installed on the VMEbus Adaptor card. Dual Port RAM provides a memory buffer; saves the cost of additional memory cards; and requires no additional VMEbus card slots.
Optional Dual Port RAM provides shared memory space accessible by random access reads and writes from either system. Dual Port RAM access uses only the bandwidth of the accessing bus. Consequently, data can be exchanged with minimal impact on the performance of the other system's bus. Both systems can access Dual Port RAM simultaneously; the Adaptor arbitrates accesses.
Dual Port RAM cards now available from Bit 3 include: 32K, 128K, 1M, 2M, 4M, and 8M byte cards.
DMA, the other method of communication, is the automatic transfer of data from one memory address to another. The Model 607 Adaptor supports two DMA techniques: DMA Controller Mode and Slave Mode DMA.
DMA Controller Mode uses the Adaptor's DMA Controller to enable high-speed data transfers from one system's memory directly into the other system's memory. Data transfer in either direction can be initiated by the GIO bus or VMEbus processor. Each DMA cycle supports transfer lengths up to 64K bytes. The DMA Controller also allows data transfers between GIO bus memory and Dual Port RAM on the VMEbus Adaptor card.
In Slave Mode DMA, the Adaptor card appears as a slave memory card. This type of DMA transfer is performed when a VMEbus DMA device (such as a disk controller) transfers data through the Adaptor directly into the GIO bus.
INTERRUPT AND ERROR HANDLING
The Adaptor supports interrupts from four sources:
Up to four interrupts can also be sent from the VMEbus system to the GIO bus. These interrupts are selected from eight possible sources: IRQ1-IRQ7 and the PT interrupt.
Although there are several potential VMEbus interrupt sources, only one GIO bus interrupt signal is used. Therefore, an 8-bit status register and an interrupt control register are available for the GIO bus interrupt handling routine to use to determine the VMEbus interrupt source.
One interrupt source, programmed interrupt to VMEbus (PR interrupt), can be generated from the GIO Adaptor card and sent to the VMEbus.
SYSTEM CONTROLLER MODE CAPABILITY
In addition to VMEbus control and bus master capabilities, the Model 607 Adaptor can provide the system controller functions. If the VMEbus system is used primarily as an expansion chassis for the GIO system, System Controller Mode eliminates the need to purchase an additional VMEbus system controller.
When configured as the system controller the Model 607 Adaptor provides the VMEbus system clock and system reset, and the Bus Error (BERR) global timeout. The VMEbus Adaptor card may be configured to be Single-Level (SGL) arbiter or a four-level bus arbiter in Priority (PRI) or Round-Robin (RRS) Mode.
MAPPING REGISTERS
All accesses from GIO to VMEbus, except Adaptor I/O registers, are through Window Mapping Registers. Each of the seven Mapping Registers controls access to 256K bytes of VMEbus address space.
Sixteen Page Mapping Registers are available to access the GIO bus for VMEbus initiated or DMA transfers. Each Page Mapping Register controls access to 4K bytes of GIO address space.
TECHNICAL HIGHLIGHTS
The VMEbus Adaptor card draws 2.6A at 5V. The GIO Adaptor card draws 1.0A at 5V.
Temperature: 0 to 60 degrees C operating;
-40 to 85 degrees C storage.
Humidity: 0% to 90% non-condensing.
REQUIRED COMPONENTS
Each Model 607 package contains: one GIO Adaptor card, one VMEbus Adaptor card, and a manual. A cable is required but is ordered separately so that you can specify the appropriate length and type for your installation.
OPTIONS
32K byte Model 400-201 128K byte Model 400-202 1M byte Model 400-203 2M byte Model 400-204 4M byte Model 400-205 8M byte Model 400-206
8' Round EMI-Shielded Model 400-107 25' Round EMI-Shielded Model 400-108
Bulkhead connector configurations (contact Bit 3 for configurations)
Two Fiber Card Model 400-5 Four Fiber Card Model 400-6 Two Fiber Module Model 400-50 Four Fiber Module Model 400-60
(Fiber-Optic Cards are for the VMEbus system only; Modules may be used with either the GIO or VMEbus system. Two Fiber-Optic Interfaces are required. For more information, request the Model 400 Fiber-Optic Interface data sheet.)
Model 963 provides IRIX compatible software support, including: a device driver, installation scripts and example programs that demonstrate use of the device driver and Model 607 Adaptor.