Difference between revisions of "DZQ11 asynchronous serial line interface"
Revision as of 04:49, 3 January 2021
The DZQ11 asynchronous serial line interface was a QBUS four port asynchronous serial line mux card for DEC computers; a re-implementation of the DZV11 (with which it is program compatible and plug compatible ). Like the original UNIBUS DZ11, it used used programmed I/O, and thus could present a considerable load on the CPU when running a high speed line.
A 64-entry FIFO buffer silo was provided on the input side. The DZQ11 could operate with full-duplex modems. It provided program-set baud rates (up to 19800 baud), but not split speed. Break could be detected or generated on each line.
Physically, it was a dual card, the M3106; a cable plugged into a Berg connector header on the card led the lines out of the computer. The pin assignments in the Berg header are mirrored, so that if the mating Berg connector is plugged in backwards, the only result is to invert the line numbering.
One choice for the cabling is the special BC11U-25 cable; it consisted of 4 separate round cables, from a Berg connector, to individual DB25 male connectors (DB-25P) wired as DTEs.
An alternative to the BC11U consisted of a flat cable from a Berg connector to a distribution panel (DEC part number 70-19964), holding 4 DB25 male connectors. (The distribution panel may be recognized by the part number on its PCB, 50-15419.)
|Control and Status Register||CSR||760100|
|Receiver Buffer Register*||RBUF||760102|
|Line Parameter Register*||LPR||760102|
|Transmit Control Register||TCR||760104|
|Modem Status Register||MSR||760106|
|Transmit Data Register||TDR||760106|
The RBUF and LPR share an address, as do the MSR and TDR: the RBUF is read only, and the LPR is write only; the MSR is read only, and the TDR is write only. Registers marked with a '*' are word-width only, no byte operations.
Control and Status Register (CSR)
- TRDY - Transmitter Ready
- TIE - Transmitter Interrupt Enable
- SA - Silo Alarm
- SAE - Silo Alarm Enable
- Tx Line - Line ready to transmit
- RDONE - Received Done
- RIE - Receiver Interrupt Enable
- MSE - Master Scan Enable
- CLR - Clear input FIFO, CSR and UARTs
- MAINT - Maintenance loopback enabled
Receiver Buffer Register (RBUF)
Line Parameter Register (LPR)
Transmit Control Register (TCR)
Modem Status Register (MSR)
Transmit Data Register (TDR)
- DZQ11 User Guide, EK-DZQ11-UG-002
- DZQ11 Technical Manual, EK-DZQ11-TM-001