Difference between revisions of "DRV11-B Direct Memory Access Interface"
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| − | The '''DRV11-B Direct Memory Access Interface''' is a parallel | + | The '''DRV11-B Direct Memory Access Interface''' is a [[parallel interface]] [[device controller]] for the [[QBUS]] which provided a pair of 16-[[bit]] parallel ports, one input, and one output; it uses [[Direct Memory Access|DMA]] to transfer data. |
It is effectively a [[half-duplex]] device; it has only a single pair of [[bus]] [[address]] and word count [[register]]s. Directional control is by the [[user]]'s device specifying whether each cycle is a DATI, DATO, or DATIO. | It is effectively a [[half-duplex]] device; it has only a single pair of [[bus]] [[address]] and word count [[register]]s. Directional control is by the [[user]]'s device specifying whether each cycle is a DATI, DATO, or DATIO. | ||
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{{16bit-bitout}} | {{16bit-bitout}} | ||
| − | [[Category:QBUS | + | [[Category: QBUS Parallel Interfaces]] |
Latest revision as of 02:54, 10 June 2020
The DRV11-B Direct Memory Access Interface is a parallel interface device controller for the QBUS which provided a pair of 16-bit parallel ports, one input, and one output; it uses DMA to transfer data.
It is effectively a half-duplex device; it has only a single pair of bus address and word count registers. Directional control is by the user's device specifying whether each cycle is a DATI, DATO, or DATIO.
It was a quad format card (M7950); connection to the user's device is via a pair of 40-pin Berg connectors.
Contents
Registers
The device has five control and buffer registers, which can be configured to any group of four sequential word locations in the I/O page; the first DRV11-B is normally configured to addresses 772410-72416. The two buffer registers share an address, responding to read or write cycles as the case might be.
| Register | Abbreviation | Address |
|---|---|---|
| Word Count Register | DRWCR | 767770 |
| Bus Address Register | DRBAR | 767772 |
| Control and Status Register | DRCSR | 767774 |
| Input Data Buffer Register | DRINBUF | 767776 (read) |
| Output Data Buffer Register | DROUTBUF | 767776 (write) |
In the register contents (below), bits which are read/write are shown in normal font, those which are read-only are in italics, and write-only in bold.
Word Count Register (DRWCR)
| WC15 <-> WC0 | |||||||||||||||
| 15 | 14 | 13 | 12 | 11 | 10 | 09 | 08 | 07 | 06 | 05 | 04 | 03 | 02 | 01 | 00 |
Bus Address Register (DRBAR)
| BA15 <-> BA1 | 0 | ||||||||||||||
| 15 | 14 | 13 | 12 | 11 | 10 | 09 | 08 | 07 | 06 | 05 | 04 | 03 | 02 | 01 | 00 |
Status Register (DRCSR)
| ERR | NEX | ATTN | MAINT | STATUS | CYCLE | RDY | IE | XAD | FNCT | GO | |||||
| 15 | 14 | 13 | 12 | 11 | 10 | 09 | 08 | 07 | 06 | 05 | 04 | 03 | 02 | 01 | 00 |
- ERR - Error; set by NEX or ATTN
- NEX - Nonexistent Memory; also write-to-zero
- ATTN - Attention; signal from user's hardware which can be tested, or cause an interrupt (below)
- MAINT - Maintenance
- STATUS - Signals from user hardware
- CYCLE - DMA cycle requested
- RDY - DRV11-B is able to accept a new command; set by ERR or WCR overflow, cleared by GO
- IE - Interrupt Enable - When set, allows setting RDY to cause an interrupt
- XAD - Extended Address; extension of BAR
- FNCT - Signals to user's hardware
- GO - Enables DMA, sent to user's hardware
Output Buffer Register (DROUTBUF)
| OUT15 <-> OUT0 | |||||||||||||||
| 15 | 14 | 13 | 12 | 11 | 10 | 09 | 08 | 07 | 06 | 05 | 04 | 03 | 02 | 01 | 00 |
Input Buffer Register (INBUF)
| IN15 <-> IN0 | |||||||||||||||
| 15 | 14 | 13 | 12 | 11 | 10 | 09 | 08 | 07 | 06 | 05 | 04 | 03 | 02 | 01 | 00 |
