DC11 asynchronous serial line interface - Revision history

Jnc: New cat header

2023-02-18T02:33:15Z

New cat header

Jnc: +manual

2022-11-24T00:50:44Z

+manual

Jnc: New cat

2022-08-17T13:53:36Z

New cat

Jnc: Addesses, power, etc

2019-09-29T13:36:08Z

Addesses, power, etc

Jnc: some details

2019-09-28T14:05:02Z

some details

Jnc: Other DF11s too

2019-09-28T13:51:17Z

Other DF11s too

Jnc: A decent start

2019-09-28T13:46:52Z

A decent start

New page

The '''DC11 asynchronous serial line interface''' is an early [[UNIBUS]] [[peripheral]] which provides an [[asynchronous serial line]] connection to a [[modem]] (Bell 103 and 202 models), using an [[EIA RS-232 serial line interface|EIA RS-232]] interface. Both input and output used [[programmed I/O]] (with separate receive and transmit [[interrupt]]s).

The line parameters:

* baud rates (4 speeds, ranging from 50 to 1800, depending on the clock module)
* character length (5-8 bits)
* input parity (even or odd)

could be set under program control. A 'break' condition on the line (i.e. continuous assertion) could also be generated and detected. The speeds available with various models were:

{| border=1
! Model !! Speeds
|-
| -AA || 300, 150, 134.5, 110
|-
| -AB || 1800, 1200, 300, 110
|-
| -AC || 1200, 600, 150, 110
|-
| -AD || 150, 134.5, 110, 50
|-
| -AE || 150, 134.5, 110, 75
|-
| -AG || 1200, 300, 150, 134.5
|-
| -AH || 1800, 1200, 134.5, 110
|-
| -AX || Other (up to 19.6K), 150, 134.5, 110
|}

==Device registers==

{| border=1
! [[Register]] !! Abbreviation !! Address
|-
|Receive Status Register || DCRCSR || 774000
|-
|Receive Buffer Regist || DCRBUF || 774002
|-
|Transmit Status Register || DCTCSR || 774004
|-
|Transmit Buffer Register || DCTBUF || 774006
|}

==Implementation==

The implementation used a single custom [[system unit]] [[backplane]], containing two indepent DC11's, each consisting of:

* M794 Interface ([[DEC card form factor|quad]])
* [[M782 Interrupt Control‎|M7821]] - Interrupt control
* [[M105 Address Selector|M105]] - Address selection
* M594 EIA level converter
* M957 data set cable connector

Board locations (as seen from the board insertion side of the backplane, not the [[wire-wrap]] pin side, as is common in [[DEC]] documentation) are:

{| class="wikitable"
! !! colspan="6" | Connector
|-
! Slot !! A !! B !! C !! D !! E !! F
|-
| 1 || colspan="2" style="text-align:center;" | UNIBUS In || M957 || M594 || M7821|| M105
|-
| 2 || G8000 filter || M454 clock || colspan="4" style="text-align:center;" | M794
|-
| 3 || power|| @ || colspan="4" style="text-align:center;" | M794
|-
| 4 || colspan="2" style="text-align:center;" | UNIBUS Out || M957 || M594 || M7821|| M105
|}

@ = M205 for -AD, -AE; M405 for -AX; or blank

[[Category: UNIBUS Serial Interfaces]]

← Older revision		Revision as of 02:33, 18 February 2023
Line 88:		Line 88:
	* [http://www.bitsavers.org/pdf/dec/unibus/DEC-11-HDCD-D_DC11_Asynchronous_Line_Interface_Sep73.pdf DC11 asynchronous line interface manual] (DEC-11-HDCD-D)		* [http://www.bitsavers.org/pdf/dec/unibus/DEC-11-HDCD-D_DC11_Asynchronous_Line_Interface_Sep73.pdf DC11 asynchronous line interface manual] (DEC-11-HDCD-D)

−	[[Category: UNIBUS ~~Serial Interfaces]]~~	+	[[Category: UNIBUS Asynchronous Serial Interfaces]]
−	~~[[Category: DEC~~ Asynchronous Serial Interfaces]]

@@ Line 79: / Line 79: @@
 Power comes in on a single-width stub card in the A3 slot (as is canonical in the [[PDP-11/20]] generation of [[PDP-11]]s).
 [[Category: UNIBUS Serial Interfaces]]
 [[Category: DEC Asynchronous Serial Interfaces]]

← Older revision		Revision as of 13:53, 17 August 2022
Line 81:		Line 81:

	[[Category: UNIBUS Serial Interfaces]]		[[Category: UNIBUS Serial Interfaces]]
		+	[[Category: DEC Asynchronous Serial Interfaces]]

@@ Line 3: / Line 3: @@
 The line parameters:
-* [[baud rate]]s (4 speeds, ranging from 50 to 1800, depending on the clock module)
+* [[baud rate]]s (4 speeds, separate for transmit and receive, ranging from 50 to 1800, depending on the clock module )
 * character length (5-8 bits)
-* stop bits (1 or 2)
+* output stop bits (1 or 2)
 * input parity (even or odd)
-could be set under program control (identical for transmit and receive). A 'break' condition on the line (i.e. continuous assertion) could also be generated and detected.
+could be set under program control. A 'break' condition on the line (i.e. continuous assertion) could also be generated and detected.
 The speeds available with various models were:
@@ Line 47: / Line 47: @@
 |Transmit Buffer Register       || DCTBUF || 774006
 |}
 ==Implementation==
@@ Line 69: / Line 71: @@
 | 2 || G8000 filter || M454 clock || colspan="4" style="text-align:center;" | M794
 |-
-| 3 || power|| @ || colspan="4" style="text-align:center;" | M794
+| 3 || Power|| @ || colspan="4" style="text-align:center;" | M794
 |-
 | 4 || colspan="2" style="text-align:center;" | UNIBUS Out || M957 || M594 || M7821|| M105
@@ Line 75: / Line 77: @@
 @ = M205 for -AD, -AE; M405 for -AX; or blank
 [[Category: UNIBUS Serial Interfaces]]

@@ Line 1: / Line 1: @@
-The '''DC11 asynchronous serial line interface''' is an early [[UNIBUS]] [[peripheral]] which provides an [[asynchronous serial line]] connection to a [[modem]] (Bell 103 and 202 models), using an [[EIA RS-232 serial line interface|EIA RS-232]] interface. Both input and output used [[programmed I/O]] (with separate receive and transmit [[interrupt]]s).
+The '''DC11 asynchronous serial line interface''' is an early [[UNIBUS]] [[peripheral]] which provides an [[asynchronous serial line]] connection to a [[modem]] (Bell 103 and 202 models), using an [[EIA RS-232 serial line interface|EIA RS-232]] interface. Both input and output used [[programmed I/O]] (with separate receive and transmit [[interrupt]]s); there was no [[buffer]]ing.
 The line parameters:
-* baud rates (4 speeds, ranging from 50 to 1800, depending on the clock module)
+* [[baud rate]]s (4 speeds, ranging from 50 to 1800, depending on the clock module)
 * character length (5-8 bits)
 * input parity (even or odd)
-could be set under program control. A 'break' condition on the line (i.e. continuous assertion) could also be generated and detected. The speeds available with various models were:
+could be set under program control (identical for transmit and receive). A 'break' condition on the line (i.e. continuous assertion) could also be generated and detected.
 {| border=1
@@ Line 29: / Line 32: @@
 |}
-Other [[DF11 Communications Line Adapter]]s could be used to interface to other serial line types.
+Other [[DF11 Communications Line Adapter]]s could be used in place of the EIA RS-232 interface card.
 ==Device registers==
@@ Line 47: / Line 50: @@
 ==Implementation==
-The implementation used a single custom [[system unit]] [[backplane]], containing two indepent DC11's, each consisting of:
+The implementation used a single custom [[system unit]] [[backplane]], containing two independent DC11's, each consisting of:
 * M794 Interface ([[DEC card form factor|quad]])

@@ Line 28: / Line 28: @@
 | -AX || Other (up to 19.6K), 150, 134.5, 110
 |}
 ==Device registers==