NEO-ZMC: Difference between revisions

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Picture courtesy of [[http://www.mvs-scans.com MVS-Scans]].
{{Chipname|Z80}} '''M'''emory '''C'''ontroller. Provides a hardwired 32KiB bank and [[Z80 bankswitching|switchable 16, 8, 4, and 2KiB banks]] arranged as a register file. To save pins, the Z80's upper address lines (A15~A8) are used for data input. The chip's write strobe is [[Z80 port map|port]] address decoded inside the system.
 
{{Chipname|Z80}} Memory Controller. Provides a hardwired 32KiB bank and switchable 16/8/4/2KiB banks arranged as a register file. To save pins, the high address lines (A15-A8) are used for data input. The chip's write strobe is [[Z80 port map|port]] address decoded inside the system.


=Pinout=
=Pinout=
Line 17: Line 15:
OpenOffice Draw file: [[File:neo-zmc.odg]]
OpenOffice Draw file: [[File:neo-zmc.odg]]


10, 11, 12 are certainly MA19, MA20, MA21.
Pins 10, 11, 12 are surely not connected since the addressing scheme doesn't allow mapping over 512KiB.


*SDA0,SDA1,SDA8~15: [[Z80]] address bus
* SDA0, SDA1, SDA8~15: Z80 address bus
*SDRD0: /Write signal from [[NEO-D0]]
* SDRD0: Decoded write signal from {{Chipname|NEO-D0}} (latch on rising edge)


=Operation=
=Operation=


SDA10,SDA9,SDA8 are bank selector and SDA1,SDA0 range size selector or rom size selector.
SDA8~15 is used for the bank number (data), SDA0 and SDA1 for selecting the bank zone.


SDA1,SDA0 = 0,0 (Z80 port 8) select bank ranges for the Z80 $F000~$F7FF range (2Kbytes) (64k M1)
{|class="wikitable"
!SDA1
!SDA0
!Z80 port
!Bank zone
!Address range
!Size
!Latch size
|-
|0||0||$08||0||$F000~$F7FF||2KiB||8 bits
|-
|0||1||$09||1||$E000~$EFFF||4KiB||7 bits
|-
|1||0||$0A||2||$C000~$DFFF||8KiB||6 bits
|-
|1||1||$0B||3||$8000~$BFFF||16KiB||5 bits
|}


SDA1,SDA0 = 0,1 (Z80 port 9) select bank ranges for the Z80 $E000~$EFFF range (4Kbytes) (128k M1)
==Details==
 
SDA1,SDA0 = 1,0 (Z80 port A) select bank ranges for the Z80 $C000~$DFFF range (8Kbytes) (256k M1)
 
SDA1,SDA0 = 1,1 (Z80 port B) select bank ranges for the Z80 $8000~$BFFF range (16Kbytes) (512k M1)
 
SDRD0 is the /write signal: the bank configuration is latched and the address output lines are changed on the rising edge.
 
 
'''Details:'''


SDRD0 must be high before configuring banks.
SDRD0 must be high before configuring banks.


To configure a bank to be accessed (e.g. bank 0 in the $8000~$BFFF range):
To configure a bank to be accessed (e.g. bank 0 in the $8000~$BFFF range):
*Set SDRD0 low (prepare for new bank configuration, outputs are tri-stated)
* Set SDRD0 low (prepare for new bank configuration, outputs are tri-stated)
*Set SDA0~15 = '''$8003''' (select bank 0 and 16k range size) Why $8003 and not just $0003 ?
* Set SDA0~15 = '''$8003''' (select bank 0 and 16k range size) Why $8003 and not just $0003 ?
*Set SDRD0 high (latch bank, ready to convert inputs to proper output signals)
* Set SDRD0 high (latch bank, ready to convert inputs to proper output signals)
*Now, when the Z80 accesses the '''$8000~BFFF''' range, NEO-ZMC will convert this the M1 ROM zone '''$00000~$03FFF''';
* Now, when the Z80 reads the '''$8000~BFFF''' range, NEO-ZMC will map this to the M1 ROM zone '''$00000~$03FFF''';


To configure a bank to be accessed (e.g. bank 1 in the $8000~$BFFF range):
To configure a bank to be accessed (e.g. bank 1 in the $8000~$BFFF range):
*Set SDRD0 low (prepare for new bank configuration, outputs are tri-stated)
* Set SDRD0 low (prepare for new bank configuration, outputs are tri-stated)
*Set SDA0~15 = '''$8103''' (select bank 1 and 16k range size) Why $8103 and not just $0103 ?
* Set SDA0~15 = '''$8103''' (select bank 1 and 16k range size) Why $8103 and not just $0103 ?
*Set SDRD0 high (latch bank, ready to convert inputs to proper output signals)
* Set SDRD0 high (latch bank, ready to convert inputs to proper output signals)
*Now, when the Z80 accesses the '''$8000~BFFF''' range, NEO-ZMC will convert this the M1 ROM zone '''$04000~$07FFF''';
* Now, when the Z80 reads the '''$8000~BFFF''' range, NEO-ZMC will map this to the M1 ROM zone '''$04000~$07FFF''';
 
To configure a bank to be accessed (e.g. bank 3 in the $C000~$DFFF range):
*Set SDRD0 low (prepare for new bank configuration, outputs are tri-stated)
*Set SDA0~15 = '''$8302''' (select bank 3 and 8k range size) Why $8302 and not just $0302 ?
*Set SDRD0 high (latch bank, ready to convert inputs to proper output signals)
*Now, when the Z80 accesses the '''$C000~DFFF''' range, NEO-ZMC will convert this the M1 ROM zone '''$06000~$07FFF''';
 
[[File:Neo-zmz operation.png|right|x400px]]
{|class="wikitable"
!Z80 address bus
(SDA0~15)
!BANK
0-31
!Window...
!...mapped to
(M1 A0~18)
|-
|$8003
|bank 00
|$8000~$BFFF
|$00000~$03FFF
|-
|$8103
|bank 01
|$8000~$BFFF
|$04000~$07FFF
|-
|$8203
|bank 02
|$8000~$BFFF
|$08000~$0BFFF
|-
|$8303
|bank 03
|$8000~$BFFF
|$0C000~$0FFFF
|-
|$8403
|bank 04
|$8000~$BFFF
|$10000~$13FFF
|-
|$8503
|bank 05
|$8000~$BFFF
|$14000~$17FFF
|-
|$8603
|bank 06
|$8000~$BFFF
|$18000~$1BFFF
|-
|$8703
|bank 07
|$8000~$BFFF
|$1C000~$1FFFF
|-
|$8803
|bank 08
|$8000~$BFFF
|$20000~$23FFF
|-
|$8903
|bank 09
|$8000~$BFFF
|$24000~$27FFF
|-
|$8A03
|bank 10
|$8000~$BFFF
|$28000~$2BFFF
|-
|$8B03
|bank 11
|$8000~$BFFF
|$2C000~$2FFFF
|-
|$8C03
|bank 12
|$8000~$BFFF
|$30000~$33FFF
|-
|$8D03
|bank 13
|$8000~$BFFF
|$34000~$37FFF
|-
|$8E03
|bank 14
|$8000~$BFFF
|$38000~$3BFFF
|-
|$8F03
|bank 15
|$8000~$BFFF
|$3C000~$3FFFF
|-
|$9003
|bank 16
|$8000~$BFFF
|$40000~$43FFF
|-
|$9103
|bank 17
|$8000~$BFFF
|$40000~$47FFF
|-
|$9203
|bank 18
|$8000~$BFFF
|$40000~$4BFFF
|-
|$9303
|bank 19
|$8000~$BFFF
|$40000~$4FFFF
|-
|$9403
|bank 20
|$8000~$BFFF
|$50000~$53FFF
|-
|$9503
|bank 21
|$8000~$BFFF
|$54000~$57FFF
|-
|$9603
|bank 22
|$8000~$BFFF
|$58000~$5BFFF
|-
|$9703
|bank 23
|$8000~$BFFF
|$5C000~$5FFFF
|-
|$9803
|bank 24
|$8000~$BFFF
|$60000~$63FFF
|-
|$9903
|bank 25
|$8000~$BFFF
|$64000~$67FFF
|-
|$9A03
|bank 26
|$8000~$BFFF
|$68000~$6BFFF
|-
|$9B03
|bank 27
|$8000~$BFFF
|$6C000~$6FFFF
|-
|$9C03
|bank 28
|$8000~$BFFF
|$70000~$73FFF
|-
|$9D03
|bank 29
|$8000~$BFFF
|$74000~$77FFF
|-
|$9E03
|bank 30
|$8000~$BFFF
|$78000~$7BFFF
|-
|$9F03
|bank 31
|$8000~$BFFF
|$7C000~$7FFFF
|}
 
Others range sets may differ from the range access here.(e.g. $8000, $8001 or $8002)


[[Category:Chips]]
[[Category:Chips]]

Revision as of 03:09, 3 November 2016

Package SOIC24
Manufacturer
First use 1995 ?
Used on cartridges

Z80 Memory Controller. Provides a hardwired 32KiB bank and switchable 16, 8, 4, and 2KiB banks arranged as a register file. To save pins, the Z80's upper address lines (A15~A8) are used for data input. The chip's write strobe is port address decoded inside the system.

Pinout

File:Neo-zmc pinout.png

OpenOffice Draw file: File:Neo-zmc.odg

Pins 10, 11, 12 are surely not connected since the addressing scheme doesn't allow mapping over 512KiB.

  • SDA0, SDA1, SDA8~15: Z80 address bus
  • SDRD0: Decoded write signal from NEO-D0 (latch on rising edge)

Operation

SDA8~15 is used for the bank number (data), SDA0 and SDA1 for selecting the bank zone.

SDA1 SDA0 Z80 port Bank zone Address range Size Latch size
0 0 $08 0 $F000~$F7FF 2KiB 8 bits
0 1 $09 1 $E000~$EFFF 4KiB 7 bits
1 0 $0A 2 $C000~$DFFF 8KiB 6 bits
1 1 $0B 3 $8000~$BFFF 16KiB 5 bits

Details

SDRD0 must be high before configuring banks.

To configure a bank to be accessed (e.g. bank 0 in the $8000~$BFFF range):

  • Set SDRD0 low (prepare for new bank configuration, outputs are tri-stated)
  • Set SDA0~15 = $8003 (select bank 0 and 16k range size) Why $8003 and not just $0003 ?
  • Set SDRD0 high (latch bank, ready to convert inputs to proper output signals)
  • Now, when the Z80 reads the $8000~BFFF range, NEO-ZMC will map this to the M1 ROM zone $00000~$03FFF;

To configure a bank to be accessed (e.g. bank 1 in the $8000~$BFFF range):

  • Set SDRD0 low (prepare for new bank configuration, outputs are tri-stated)
  • Set SDA0~15 = $8103 (select bank 1 and 16k range size) Why $8103 and not just $0103 ?
  • Set SDRD0 high (latch bank, ready to convert inputs to proper output signals)
  • Now, when the Z80 reads the $8000~BFFF range, NEO-ZMC will map this to the M1 ROM zone $04000~$07FFF;
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