Interlan NI1010A/NI2010A Ethernet Communications Controller

The Interlan NI1010A and NI2010A are Ethernet network interfaces for the UNIBUS and QBUS respectively. (The two device controllers are very similar in programming terms, so they are covered in this single article.)

They use DMA to transfer data to and from buffers in main memory. They have an on-board FIFO buffer which can hold up to 13.5K bytes of inbound data; the host can pre-queue up to 16 input buffer DMA requests.

The NI1010A is a single hex board. The NI2010A is a quad board, with a large daughter card; they take two slots, but only the mother card has edge fingers to plug in. A grant continuity card is supplied, to plug into the second slot, to carry the QBUS' bus grant lines through the slot.

Their bus address and interrupt vectors can be set via DIP switches on the board (to 7mnnp0, where m can be 6 or 7, and p 0,2,4 or 6; and 0xx0, respectively), but their defaults are 0764000 and 0340.

There are two interrupt vectors; 0xx0 for 'Receive DMA done' and 0xx4 for 'Command done'.

Device registers

The NI1010A controller includes 3 registers, and the NI2010A 4 (the optional extra register is needed because of the larger address space on the QBUS):

Register	Abbreviation	Address
Control Status Register	CSR	764000
Bus Address Register	BAR	764002
Byte Count Register	BCR	764004
Bus Address Extension Register NI2010A only	BER	774006

The Bus Address Extension Register was enabled by a switch; i.e. the NI2010A could be set to be identical, programmatically, to the NI1010A, at the cost of not being able to use more than 256KB of main memory.

In the register contents (below), bits which are read/write or unused are shown in normal font, those which are read-only are in italics, and those which are write-only are shown in bold.

764000: Control Status Register (CSR)

XM		FUNC						CDN	CIE	RDN	RIE	STAT
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

Bits are:

Bits	Use
XM	Extended address bits A17 and A16
FUNC	Command Function Code
CDN	Command Done
CIE	Command Done Interrupt Enable
RDN	Receive DMA Done
RIE	Receive DMA Done Interrupt Enable
STAT	Command Status Code

Reading the CSR clears the two 'done' bits. The extended address bits are disabled on the NI2010A when the BER is enabled.

Command function codes are:

Code	Command
01	Set loopback
02	Set internal loopback
03	Clear loopback
04	Set promiscuous receive
05	Clear promiscuous receive
06	Set receive-on-error
07	Clear receive-on-error
10	Go offline
11	Go online
12	Run diagnostic
15	Set insert source address
16	Clear insert source address
17	Set network address to default
20	Set receive all multicast
21	Clear receive all multicast
22	Perform loopback test
23	Perform collision detection test
30	Report and clear stats
31	Report collision delay times
40	Supply receive buffer
50	Load transmit data
51	Load transmit data and send
52	Load group address(es)
53	Delete group address(es)
54	Load physical network address
60	Flush input buffer queue
77	Reset

Command status codes are:

Code	Status
00	Success
01	Success with retries
02	Illegal command
03	Inappropriate command
04	Failure
05	Buffer size exceeded
06	Frame too small
10	Excessive collisions
12	Buffer alignment error
13	No heartbeat detected
14	No CRC error occurred
15	Inappropriate CRC error
16	Last data byte not received
17	Non-existent memory

764002: Bus Address Register (BAR)

BA15 <---> BA00
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

Write-only register.

764004: Byte Count Register (BCR)

BC15 <---> BC0
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

Write-only register.

7764006: Bus Address Extension Register (BER)

Unused										BA21 <---> BA16
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

Write-only register.

Note: This register is present in the NI2010A only.