RX211 floppy disk controller - Revision history

Jnc: /* Further reading */ +Two Potential Problems with the RXV21

2024-07-29T17:23:14Z

‎Further reading: +Two Potential Problems with the RXV21

Jnc: /* Further reading */ +Bootstrap for RX02

2024-07-29T01:04:24Z

‎Further reading: +Bootstrap for RX02

Jnc: /* External links */ Manual + FMPS

2022-11-06T13:06:30Z

‎External links: Manual + FMPS

Jnc: Better naming system, links, avoid redir

2020-10-29T15:42:39Z

Better naming system, links, avoid redir

Jnc: +cat

2018-09-04T00:55:19Z

+cat

Jnc: Reasonable complete

2018-03-27T22:17:37Z

Reasonable complete

New page

The '''RX211''' and '''RXV21''' are controllers for the [[RX0x floppy drive|RX02]] )and also the RX01) [[diskette|floppy disk]] [[disk|drives]] for the [[UNIBUS]] and [[QBUS]], respectively.

They have an identical programming interface; both use [[Direct Memory Access|DMA]] to transfer information between [[main memory]] and the floppy.

==Device registers==

{| border=1
! Register !! Abbreviation !! Address
|-
|Command and Status Register || RX2CS || 777170
|-
|Data Buffer Register || RX2DB || 777172
|}

===777170: Command and Status Register (RX2CS)===
{{16bit-header}}
| Error || Initialize || colspan=2 | Extended Address || RX02 || colspan=2 | Unused || Density || Transfer Request || Interrupt Enable || Done || Unit Select || colspan=3 | Function || Go
{{16bit-bitout}}

The function codes are:
{| class="wikitable"
! Code !! Function
|-
| 0 || Fill Buffer
|-
| 1 || Empty Buffer
|-
| 2 || Write Sector
|-
| 3 || Read Sector
|-
| 4 || Set Media Density
|-
| 5 || Read Status
|-
| 6 || Write Deleted Data Sector
|-
| 7 || Read Error Register
|}

===777172: Data Buffer Register (RX2DB)===

This register contains one of several 'virtual' registers, depending on the function in progress.

The 'Transfer Request' bit in the RXCS is used to indicate which virtual register is in use at any given time.

====Track Address (RX2TA)====
{{16bit-header}}
| colspan=8 | Unused || 0 || colspan=7 | Track
{{16bit-bitout}}

====Sector Address (RX2SA)====
{{16bit-header}}
| colspan=8 | Unused || 0 || 0 || 0 || colspan=5 | Sector
{{16bit-bitout}}

====Word Count (RX2WC)====
{{16bit-header}}
| colspan=8 | Unused || 0 || colspan=7 | Count
{{16bit-bitout}}

====Bus Address (RX2BA)====
{{16bit-header}}
| colspan=16 | Address
{{16bit-bitout}}

====Data Buffer (RX2DB)====
{{16bit-header}}
| colspan=8 | Unused || colspan=8 | Data
{{16bit-bitout}}

Note the name clash between this virtual register, and the actual register which contains it.

====Error and Status (RX2ES)====
{{16bit-header}}
| colspan=4 | Unused || NXM || WC Overflow || Reserved || Unit Select || Drive Ready || Deleted Data || Drive Density || Density Error || AC Low || Initialize Done || Reserved || CRC Error
{{16bit-bitout}}

====Error (RX2ER)====
{{16bit-header}}
| colspan=8 | Unused || colspan=8 | Error Code
{{16bit-bitout}}

Error code values:

{| class="wikitable"
! Value !! Meaning
|-
| 0010 || Drive 0 failed to see home on Initialize
|-
| 0020 || Drive 1 failed to see home on Initialize
|-
| 0040 || Tried to access a track greater than 76
|-
| 0050 || Home was found before desired track was reached
|-
| 0070 || Desired sector could not be found after looking at 52 headers (2 revolutions)
|-
| 0110 || More than 40 μsec and no SEP clock seen
|-
| 0120 || A preamble could not be found
|-
| 0130 || Preamble found but no ID mark found within allowable time span
|-
| 0140 || [[CRC]] error found on what we thought was a header
|-
| 0150 || The header track address of a good header does not compare with the desired track
|-
| 0160 || Too many tries for an IDAM (identifies header)
|-
| 0170 || Data AM not found in allotted time
|-
| 0200 || CRC error on reading the sector from the disk
|-
| 0220 || R/W electronics failed maintenance test mode
|-
| 0230 || Word count overflow
|-
| 0240 || Density error
|-
| 0250 || Wrong key word for set media density command
|}

← Older revision		Revision as of 17:23, 29 July 2024
Line 125:		Line 125:

	* ''Bootstrap for RX02'', [[MicroNote]] #065		* ''Bootstrap for RX02'', [[MicroNote]] #065
		+	* ''Two Potential Problems with the RXV21 Interface'', MicroNote #092

	==External links==		==External links==

@@ Line 121: / Line 121: @@
 | 0250 || Wrong key word for set media density command
 |}
 ==External links==

@@ Line 121: / Line 121: @@
 | 0250 || Wrong key word for set media density command
 |}
 [[Category: UNIBUS Storage Controllers]]
 [[Category: QBUS Storage Controllers]]

@@ Line 1: / Line 1: @@
-The '''RX211''' and '''RXV21''' are controllers for the [[RX0x floppy drive|RX02]] )and also the RX01) [[diskette|floppy disk]] [[disk|drives]] for the [[UNIBUS]] and [[QBUS]], respectively.
+The '''RX211''' and '''RXV21''' are controllers for the [[RX01/02 floppy drive|RX02]] (and also the [[RX01/02 floppy drive|RX01]]) [[diskette|floppy disk]] [[disk|drives]] for the [[UNIBUS]] and [[QBUS]], respectively.
 They have an identical programming interface; both use [[Direct Memory Access|DMA]] to transfer information between [[main memory]] and the floppy.
@@ Line 103: / Line 103: @@
 | 0130 || Preamble found but no ID mark found within allowable time span
 |-
-| 0140 || [[CRC]] error found on what we thought was a header
+| 0140 || [[Cyclic redundancy check|CRC]] error found on what we thought was a header
 |-
 | 0150 || The header track address of a good header does not compare with the desired track
@@ Line 122: / Line 122: @@
 |}
-[[Category:UNIBUS Storage Controllers]]
+[[Category: UNIBUS Storage Controllers]]
-[[Category:QBUS Storage Controllers]]
+[[Category: QBUS Storage Controllers]]

← Older revision		Revision as of 00:55, 4 September 2018
Line 121:		Line 121:
	\| 0250 \|\| Wrong key word for set media density command		\| 0250 \|\| Wrong key word for set media density command
	\|}		\|}
		+
		+	[[Category:UNIBUS Storage Controllers]]
		+	[[Category:QBUS Storage Controllers]]