Revision as of 01:15, 17 November 2016

Sanyo Programmable Controler ("PUPPET") used in CD systems. Handles DMA to DRAM. Later replaced by the LC98000. Both publicly available datasheets for these ICs are incomplete.

DMA

The datasheet describes a 16-instruction microcode that is used to control DMA registers and transfer. There is no public documentation of this (?) and all open source emulates use HLE to emulate it. 18 bytes of microcode are written by the BIOS for each type of transfer to register. The microcode can be written using 9 word writes or 4 longword writes and one word write (verified).

This can be used as a reference to reverse engineer the microcode format or to control the DMA hardware without BIOS routines. These were tested working on top-loading CDM 4-x boards as part of a test routine.

Set $FF0061 to $00
Write microcode to $FF007E+
Set registers as defined by microcode
Set $FF0061 to $40

Word fill

dc.w $FFDD,$FCF5,$92F6,$2602,$FDFF,$FFFF,$FCF5,$8AF0,$1609 (CDM 4-x & CDZ)

$FF0064: 32bit destination
$FF006C: 16bit word to fill with
$FF0070: 32bit length in words

Word copy

dc.w $FE6D,$FCF5,$82BF,$F693,$BF29,$02FD,$FFFF,$F97D,$FCF5 (CDM 4-x)
dc.w $FE3D,$FCF5,$82BF,$93BF,$F629,$02FD,$FFFF,$F17D,$FCF5 (CDZ)

$FF0064: 32bit source
$FF0068: 32bit destination
$FF0070: 32bit length in words

Address fill

dc.w $FEF5,$FCF5,$92E8,$BE96,$F629,$02FD,$FFFF,$FC3D,$FCF5 (CDM 4-x & CDZ)

$FF0064: 32bit destination
$FF0070: 32bit length in longs (number of addresses to copy)

Byte copy

dc.w $F2DD,$FCF5,$82F6,$93DA,$BE93,$DABE,$2C02,$FDFF,$FFCD (CDM 4-x)
dc.w $E2DD,$FCF5,$82BE,$93DA,$BE93,$DABE,$F62D,$02FD,$FFFF (CDZ)

$FF0064: 32bit source
$FF0068: 32bit destination
$FF0070: 32bit length in words (as in pairs of bytes)

Used for copying data to 8bit memory, such as PCM RAM.

Read word from source
Swap word
Write word to destination
Swap word again
Write word to destination + 2
source += 2, destination += 4
Repeat (length) times

IRQs

There is a programmable IRQ controller in this chip but it's not known if the NEO-MGA is used for this instead. DMA is used to copy the 2KB of data into work RAM and an interrupt is generated to signal this after every sector copied (and for other events too?). This is emulated at least by MESS.

Datasheet

Incomplete official datasheet: [[1]]

@@ Line 4: / Line 4: @@
 Both publicly available datasheets for these ICs are incomplete.
-==DMA==
+=DMA=
 The datasheet describes a 16-instruction microcode that is used to control DMA registers and transfer.  There is no public documentation of this (?) and all open source emulates use HLE to emulate it.  18 bytes of microcode are written by the BIOS for each type of transfer to register. The microcode can be written using 9 word writes or 4 longword writes and one word write (verified).
@@ Line 15: / Line 15: @@
 *Set $FF0061 to $40
-===Word fill===
+==Word fill==
 <pre>
@@ Line 25: / Line 25: @@
 </pre>
-===Word copy===
+==Word copy==
 <pre>
@@ Line 36: / Line 36: @@
 </pre>
-===Address fill===
+==Address fill==
 <pre>
@@ Line 45: / Line 45: @@
 </pre>
-===Byte copy===
+==Byte copy==
 <pre>
@@ Line 66: / Line 66: @@
 *Repeat (length) times
-==IRQ==
+=IRQs=
 There is a programmable IRQ controller in this chip but it's not known if the [[NEO-MGA]] is used for this instead.  DMA is used to copy the 2KB of data into work RAM and an interrupt is generated to signal this after every sector copied (and for other events too?).  This is emulated at least by MESS.
-==Datasheet==
+=Datasheet=
 Incomplete official datasheet: [[http://www.datasheetcatalog.org/datasheet/sanyo/ds_pdf_e/LC8953.pdf]]
 [[Category:Chips]]
+[[Category:CD systems]]

LC8953: Difference between revisions