DU11 synchronous serial line interface - Revision history

Jnc: New cat scheme

2023-02-18T02:21:14Z

New cat scheme

Jnc: /* External links */ +manuals, EngDrw

2022-11-17T02:00:10Z

‎External links: +manuals, EngDrw

Jnc: New cat

2022-08-15T19:29:40Z

New cat

Jnc: +See also

2021-08-04T00:32:44Z

+See also

Jnc: typos

2021-08-03T17:37:55Z

typos

Jnc: Basically complete

2021-08-03T14:53:06Z

Basically complete

New page

The '''DU11''' is an early [[synchronous serial line]] [[peripheral|interface]] for the [[UNIBUS]]. Like the earlier [[DP11-A synchronous serial line interface|DP11-A]], it used [[programmed I/O]] (with separate receive and transmit [[interrupt]]s) to transfer data; it was double-[[buffer]]ed for both input and output.

It provided an [[EIA RS-232 serial line interface|EIA RS-232]] interface (to Bell 200 series [[modem]]s, such as the model 201, and equivalents), and optionally a [[20mA current loop serial line interface|current loop]] interface (to Bell 300 series modems, such as the model 303, and equivalents). [[Baud rate]]s of up to 9.6K bits/second were supported by the EIA interface, and up to 100K bits/second by the current loop interface.

The [[character]] length (5, 6, 7 or 8 [[bit]]s), and the [[sync character]], were selectable; [[parity]] (even or odd) was optionally supported for error detection. It could operate in either [[half-duplex]] or [[full-duplex]] mode. All configuration, as well as all the modem control leads, could be set under program control. A [[jumper]] allows configuration of whether one or two contiguous sync characters is needed for synchronization.


It was a [[DEC card form factor|quad-width]] card, the '''M7822'''; it plugged into an [[Small Peripheral Controller|SPC]] slot. A [[Berg connector|Berg header]] on the card provided the 'native' EIA interface; alternatively, when the M7822 card was plugged into a [[DD11-B backplane]], a two single-card [[DF11 Communications Line Adapter]] set could be used to connect to current loop modems which were not supported 'natively' by the M78222 (such as the Bell 303). Optionally, the DFC11-A (installed instead of a DF11) allowed use of an internal [[clock]] (when two interfaces were connected directly, without modems)..

==Registers==

{| border=1
! Register !! Abbreviation !! Address
|-
|Receiver Status Register || RxCSR || 16xx10
|-
|Receiver Data Buffer Register (read only) || RxDBUF || 16xx12
|-
|Parameter Control Register (write only) || PARCSR || 16xx12
|-
|Transmitter Status Register || TxCSR || 16xx14
|-
|Transmitter Data Buffer Register || TxDBUF || 16xx16
|}

===16xx10: Receiver Status Register (RxCSR)===

{{16bit-header}}
| DSCA || RING || CTS || CARR || RACT || SECRCV || DSR || SSYNC || RDN || RIE || DSIE || SSYNC || SECXMT || RTS || DTR || Unused
{{16bitoctal-bitout}}

* DSC - Data Set Change; set for any change on Ring, Carrier, Data Set Ready, Clear to Send or Secondary Received Data lines
* RING - Ring Indicator
* CTS - Clear to Send
* CARR - Carrier
* RACT - Receiver Active; setting dependent on the internal/external synchronization mode
* SECRCV - Secondary Received Data
* DSR - Data Set Ready
* SSYNC - Strip Sync; sync characters are discarded
* RDN - Receive Done Flag; set when the receive buffer is filled with an assembled character
* RIE - Receive Interrupt Enable; allows an input interrupt when Receive Done is set
* DSIE - Data Set Interrupt Enable; allows an input interrupt when DSC is set
* SSYNC - Search Synchronization; when set, the receiver looks for synch character(s)
* SECXMT - Secondary Transmit Data
* RTS - Request to Send
* DTR - Data Terminal Ready

===16xx12 (read): Receiver Data Buffer Register (RxDBUF)===

{{16bit-header}}
| ERR || OVR || Rsvd || PARERR || colspan=4 | Rsvd || colspan=8 | RDBUF
{{16bitoctal-bitout}}

* ERR - Error
* OVR - Overrun
* PARERR - Parity Error
* RABO - Received Abort
* REOM - End of Received Message
* RSOM - Start of Received Message
* RDBUF - Receiver Data Buffer

===16xx12 (write): Parameter Control Register (PARCSR)===

{{16bit-header}}
| colspan=2 | Rsvd || colspan=2 | MODE || colspan=2 | LEN || PAR EN || EVEN PAR || colspan=8 | SYNC
{{16bitoctal-bitout}}

* MODE - Synchronous Mode (10=External, 11=Internal)
* LEN - Length (00=5, 01=6, 10=7, 11=8)
* PAR EN - Parity Enable
* EVEN PAR - Even Parity selected
* SYNC - Sync Character

===16xx14: Transmitter Status Register (TxCSR)===

{{16bit-header}}
| DNA || MD || MCLK || colspan=2 | MMS || MBW || Unused || MR || TDN || TIE || DNAIE || SEND || HDFD || colspan=2 | Unused || BRK
{{16bitoctal-bitout}}

* DNA - Data Not Available
* MTDO - Maintenance Data
* MCLK - Maintenance Clock
* MMSB - Maintenance Mode Select (01=Internal, 10=External, 11=Internal systems)
* MID - Maintenance Bit Window
* DRST - Master Reset
* TDN - Transmitter Done; set when the Transmitter Data Buffer is ready for the next character
* TIE - Transmitter Interrupt Enable; allows a transmit interrupt when Transmit Done is set
* DNAIE - Data Not Available Interrupt Enable
* SEND - Send; enables the transmitter logic
* HDFD - Half-Duplex/Full-Duplex
* BRK - Send [[Asynchronous serial line|Break]]

===16xx16: Transmitter Data Buffer Register (TxDBUF)===

{{16bit-header}}
| colspan=8 | Unused || colspan=8 | TDBUF
{{16bitoctal-bitout}}

* TDBUF - Transmitter Data Buffer

[[Category:UNIBUS Serial Interfaces]]

← Older revision		Revision as of 02:21, 18 February 2023
Line 106:		Line 106:
	* [http://www.bitsavers.org/pdf/dec/unibus/DU11_RevD_Engineering_Drawings_Jul75.pdf DU11 Engineering Drawings]		* [http://www.bitsavers.org/pdf/dec/unibus/DU11_RevD_Engineering_Drawings_Jul75.pdf DU11 Engineering Drawings]

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

@@ Line 99: / Line 99: @@
 * [[DUP11 synchronous serial line interface]]
 [[Category: UNIBUS Serial Interfaces]]
 [[Category: DEC Synchronous Serial Interfaces]]

← Older revision		Revision as of 19:29, 15 August 2022
Line 100:		Line 100:
	* [[DUP11 synchronous serial line interface]]		* [[DUP11 synchronous serial line interface]]

−	[[Category:UNIBUS Serial Interfaces]]	+	[[Category: UNIBUS Serial Interfaces]]
		+	[[Category: DEC Synchronous Serial Interfaces]]

← Older revision		Revision as of 00:32, 4 August 2021
Line 95:		Line 95:

	* TDBUF - Transmitter Data Buffer		* TDBUF - Transmitter Data Buffer
		+
		+	==See also==
		+
		+	* [[DUP11 synchronous serial line interface]]

	[[Category:UNIBUS Serial Interfaces]]		[[Category:UNIBUS Serial Interfaces]]

@@ Line 27: / Line 27: @@
 {{16bit-header}}
-| DSCA || RING || CTS || CARR || RACT || SECRCV || DSR || SSYNC || RDN || RIE || DSIE || SSYNC || SECXMT || RTS || DTR || Unused
+| DSC || RING || CTS || CARR || RACT || SECRCV || DSR || STRSYN || RDN || RIE || DSIE || SRCHSYN || SECXMT || RTS || DTR || Unused
 {{16bitoctal-bitout}}
@@ Line 37: / Line 37: @@
 * SECRCV - Secondary Received Data
 * DSR - Data Set Ready
-* SSYNC - Strip Sync; sync characters are discarded
+* STRSYN - Strip Sync; sync characters are discarded
 * RDN - Receive Done Flag; set  when the receive buffer is filled with an assembled character
-* RIE - Receive Interrupt Enable; allows an input interrupt when Receive Done is set
+* RIE - Receiver Interrupt Enable; allows an input interrupt when Receive Done is set
 * DSIE - Data Set Interrupt Enable; allows an input interrupt when DSC is set
-* SSYNC - Search Synchronization; when set, the receiver looks for synch character(s)
+* SRCHSYN - Search Synchronization; when set, the receiver looks for synch character(s)
 * SECXMT - Secondary Transmit Data
 * RTS - Request to Send
@@ Line 49: / Line 49: @@
 {{16bit-header}}
-| ERR || OVR || Rsvd || PARERR || colspan=4 | Rsvd ||  colspan=8 | RDBUF
+| ERR || OVR || Unused || PARERR || colspan=4 | Unused ||  colspan=8 | RDBUF
 {{16bitoctal-bitout}}
@@ Line 55: / Line 55: @@
 * OVR - Overrun
 * PARERR - Parity Error
 * RDBUF - Receiver Data Buffer
@@ Line 63: / Line 60: @@
 {{16bit-header}}
-| colspan=2 | Rsvd || colspan=2 | MODE || colspan=2 | LEN || PAR EN || EVEN PAR ||  colspan=8 | SYNC
+| colspan=2 | Unused || colspan=2 | MODE || colspan=2 | LEN || PAR EN || EVEN PAR ||  colspan=8 | SYNC
 {{16bitoctal-bitout}}
-* MODE - Synchronous Mode (10=External, 11=Internal)
+* MODE - Synchronous Mode Select (10=External, 11=Internal)
 * LEN - Length (00=5, 01=6, 10=7, 11=8)
 * PAR EN - Parity Enable
@@ Line 79: / Line 76: @@
 * DNA - Data Not Available
-* MTDO - Maintenance Data
+* MD - Maintenance Data
 * MCLK - Maintenance Clock
-* MMSB - Maintenance Mode Select (01=Internal, 10=External, 11=Internal systems)
+* MMS - Maintenance Mode Select (01=Internal, 10=External, 11=Internal systems)
-* MID - Maintenance Bit Window
+* MBW - Maintenance Bit Window
-* DRST - Master Reset
+* MR - Master Reset
 * TDN - Transmitter Done; set when the Transmitter Data Buffer is ready for the next character
 * TIE - Transmitter Interrupt Enable; allows a transmit interrupt when Transmit Done is set