CHA256: Difference between revisions

From NeoGeo Development Wiki
Jump to navigation Jump to search
(Created page with "===C ROMs=== Up to 8 * 32Mbit ROMs (27C322) can be used for a maximum of 256Mbit. 27C800/27C160 can also be used depending on jumper configuration. The size of largest ROM i...")
 
No edit summary
(5 intermediate revisions by 2 users not shown)
Line 1: Line 1:
[[File:Cha256_mvs.jpg|thumb|256px]]
===C ROMs===
===C ROMs===


Line 10: Line 12:
!Jumper set
!Jumper set
|-
|-
|8Mbit
|1MiB
|J5+J6
|J5+J6
|-
|-
|16Mbit
|2MiB
|J7+J8
|J7+J8
|-
|-
|32Mbit
|4MiB
|J9+J10
|J9+J10
|}
|}


A [[NEO-273]] and a LS74 are used to address C ROM. The LS74 provides the 2 most significant bits. The LS139 enables one of four pairs of C ROMs using 2 address inputs depending on which 2 jumpers are connected.
These jumpers seem to apply only to those two ROMs, if the ROMs are not present, simply leave both jumpers unconnected.
 
{| class="wikitable"
|-
!C1/2 ROM type
!Jumper set
|-
|<4MiB
|J15
|-
|4MiB
|J11
|}
 
{| class="wikitable"
|-
!C3/4 ROM type
!Jumper set
|-
|<4MiB
|J16
|-
|4MiB
|J12
|}


{| class="wikitable"
{| class="wikitable"
|-
|-
!J5
!C5/6 ROM type
!J7
!Jumper set
!J9
!?
|-
|-
|ROM number LSB is A19
|<4MiB
|ROM number LSB is A20
|J17
|ROM number LSB is LS74 Q2 (A21 ?)
|-
|?
|4MiB
|J13
|}
|}


{| class="wikitable"
{| class="wikitable"
|-
|-
!J6
!C7/8 ROM type
!J8
!Jumper set
!J10
!?
|-
|-
|ROM number MSB is A20
|<4MiB
|ROM number MSB is LS74 Q2 (A21 ?)
|J18
|ROM number MSB is LS74 Q1 (A22 ?)
|-
|?
|4MiB
|J14
|}
|}
A [[NEO-273]] and a LS74 are used to address C ROM. The LS74 provides the 2 most significant bits. The LS139 enables one of four pairs of C ROMs using 2 address inputs depending on which 2 jumpers are connected.


*Max 256Mbit C ROM (8x 32Mbit)
*Max 256Mbit C ROM (8x 32Mbit)
{| class="wikitable"
|-
!M1 ROM size
!Jumper set
|-
|64KiB
|J1+J4
|-
|128KiB
|J2+J3
|}
*[[NEO-273]]
*[[NEO-273]]
*[[NEO-ZMC]]
*[[NEO-ZMC]]
*LS139,LS74
*LS139,LS74
==AES version==
{| class="wikitable"
|-
!C ROM type
!Jumper set
|-
|<4MiB
|J15+J16+J17+J18
|-
|4MiB
|J11+J12+J13+J14
|}
{| class="wikitable"
|-
!EVEN delay
!Jumper set
|-
|1 gate
|J19
|-
|2 gates
|J20
|}
[[Category:Cartridge boards]]

Revision as of 20:29, 13 April 2021

C ROMs

Up to 8 * 32Mbit ROMs (27C322) can be used for a maximum of 256Mbit. 27C800/27C160 can also be used depending on jumper configuration.

The size of largest ROM is selected using a pair of jumpers. The rest should be left unconnected.

Largest C ROM Jumper set
1MiB J5+J6
2MiB J7+J8
4MiB J9+J10

These jumpers seem to apply only to those two ROMs, if the ROMs are not present, simply leave both jumpers unconnected.

C1/2 ROM type Jumper set
<4MiB J15
4MiB J11
C3/4 ROM type Jumper set
<4MiB J16
4MiB J12
C5/6 ROM type Jumper set
<4MiB J17
4MiB J13
C7/8 ROM type Jumper set
<4MiB J18
4MiB J14

A NEO-273 and a LS74 are used to address C ROM. The LS74 provides the 2 most significant bits. The LS139 enables one of four pairs of C ROMs using 2 address inputs depending on which 2 jumpers are connected.

  • Max 256Mbit C ROM (8x 32Mbit)
M1 ROM size Jumper set
64KiB J1+J4
128KiB J2+J3

AES version

C ROM type Jumper set
<4MiB J15+J16+J17+J18
4MiB J11+J12+J13+J14
EVEN delay Jumper set
1 gate J19
2 gates J20