Applix SCSI and Memory board


Components

TTL chips

U51		74F74		Fast D-type flip flops, divide 30 MHz to 15 MHz
U41		74F157		Fast multiplexers for SRAM MA22-20
U35		74F157		Fast multiplexers for SRAM MA19-16
U43		74F157		Fast multiplexers for SRAM MA15-12
U39		74LS393		Counter	divides 15 MHz by 256
U50		74LS245		SRAM  D15-8 buffer
U57		74LS245		SRAM   D7-0 buffer
U45		74LS245		DRAM MD15-8 buffer
U46		74LS245		DRAM  MD7-0 buffer
U52,53,54,55	74LS244		Bus signal buffers

Memory chips

U1-32		?		DRAM, 256K x 4-bit	
U36,42,44	CY7C128		SRAM

Programmable logic

U33		PAL20L8		SCSI logic
U34		PAL20L8		SMMUX	Multiplexer MA8-5 (4 bits)
U38		PAL20L8		SMMS	Memory
U40		PAL20L8		SMMLX	Multiplexer MA4-0 (9 bits)
U58		PAL20L8		SMBI	Bus Interface
U46		PAL20R8		SMCAS	CAS decoder
U47		PAL16R8		SMMT	Memory Timing
U49		PAL20L8		SMSR	Static RAM controller

Register offsets (in hex)

U37		5380		SCSI controller

SCSI controller (5380)

Base address = ffde00.

Register offsets (in hex)

00 : Data
08 : Initiator command
10 : Mode
18 : Target command
20 : Current bus status
28 : Bus and status
30 : Input data
38 : Reset parity and interrupts.

DMA registers

00 : DMA output
30 : DMA input
80 : DMA output with EOP
b0 : DMA input  with EOP.

SRAM

f80000 - ffffff	: MMU translation and history RAM.

DRAM

000000 - 0fffff	: 1st Megabyte of RAM
100000 - 1fffff	: 2nd Megabyte of RAM
200000 - 2fffff	: 3rd Megabyte of RAM
300000 - 3fffff	: 4th Megabyte of RAM.

DRAM chip map

 RAS 
10
CAS 0191732000000 Base
12101831080000
23111930100000
34122029180000
45132128200000
56142227280000
67152326300000
78162425380000
 15-1211-87-43-0 
Data bus bits