ZX Spectrum ULA: Difference between revisions

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ZX Spectrum ULA (view source)

Revision as of 01:27, 2 January 2018

3,925 bytes added ,  2 January 2018
m
→‎5C and 6C ULAs: Remove duplicated pin number
(IO → I/O as per Zilog Z80 and Spectrum BASIC manuals and Wikipedia)
m (→‎5C and 6C ULAs: Remove duplicated pin number)
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The [[ZX Spectrum 16K/48K]] ULA went through [[#ULA versions|multiple revisions]] and is either a 5C or 6C series Ferranti ULA.
The [[ZX Spectrum 16K/48K]] ULA went through [[#ULA versions|multiple revisions]] and is either a 5C or 6C series Ferranti ULA.


On a [[ZX Spectrum+ 128K]], or [[ZX Spectrum +2]] the ULA is the Ferranti 7K010E (labelled Amstrad 40056 in +2)
On a [[ZX Spectrum 128]], or [[ZX Spectrum +2]] the ULA is the Ferranti 7K010E (later labelled Amstrad 40056)


The ZX Spectrum +2A/2B, +3/3B machines use an entirely different gate array. See [[The Amstrad gate array]]
The [[ZX Spectrum +2A/2B, +3/3B|ZX Spectrum +2A, +3, +2B, and +3B]] use an entirely different gate array. See [[The Amstrad gate array]]


Sinclair also experimented with an alternative [[#AMI SAGA|AMI SAGA]] chip in a special batch.
Sinclair also experimented with an alternative [[#AMI SAGA|AMI SAGA]] chip in a special batch.
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== Flash attribute timing bug ==
== Flash attribute timing bug ==
The flash attribute suffers from a timing bug, in that the flash signal is not in sync with the pixel with which it is XORed.  On frames where the flash signal is inactive, this bug is not apparent, but where the flash signal is active, and used within an attribute block, flash will also affect the very right-hand edge of the preceding block, and in attribute blocks where flash is not set, flash will fail to affect the very right-hand edge of the preceding block.  This bug only affects instances where there is a transition in pixel value between one character block and the next, but the flash attribute reverses that transition.  As such, this does not affect the Spectrum's flashing cursor, as its graphic has edges matching the surrounding "paper" and not the ink.  No existing emulator known to implement this display artifact.
The flash attribute suffers from a timing bug, in that the flash signal is not in sync with the pixel with which it is XORed.  On frames where the flash signal is inactive, this bug is not apparent, but where the flash signal is active, and used within an attribute block, flash will also affect the very right-hand edge of the preceding block, and in attribute blocks where flash is not set, flash will fail to affect the very right-hand edge of the preceding block.  This bug only affects instances where there is a transition in pixel value between one character block and the next, but the flash attribute reverses that transition.  As such, this does not affect the Spectrum's flashing cursor, as its graphic has edges matching the surrounding "paper" and not the ink.  No existing emulator known to implement this display artifact.
== Pinouts ==
=== 5C and 6C ULAs ===
<div style="font-family:'Lucida Console', monospace">
{|
| style="text-align:right;" |
{{overline|CAS}}<br>
{{overline|WR}}<br>
{{overline|RD}}<br>
{{overline|WE}}<br>
A<sub>0</sub><br>
A<sub>1</sub><br>
A<sub>2</sub><br>
A<sub>3</sub><br>
A<sub>4</sub><br>
A<sub>5</sub><br>
A<sub>6</sub><br>
{{overline|INT}}<br>
(+5V) V<sub>CC-Logic</sub><br>
(+5V) V<sub>CC-IO</sub><br>
U<br>
V<br>
{{overline|Y}}<br>
D<sub>0</sub><br>
KB<sub>0</sub><br>
KB<sub>1</sub>
| style="border: 1px solid black" |
1&nbsp;°&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;40<br>
2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;39<br>
3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;38<br>
4&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;37<br>
5&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;36<br>
6&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;35<br>
7&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;34<br>
8&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;33<br>
9&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;32<br>
10&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;31<br>
11&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;30<br>
12&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;29<br>
13&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;28<br>
14&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;27<br>
15&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;26<br>
16&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;25<br>
17&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;24<br>
18&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;23<br>
19&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;22<br>
20&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;21
||
GND (0V)<br>
OSC<br>
{{overline|MREQ}}<br>
A<sub>15</sub><br>
A<sub>14</sub><br>
{{overline|RAS}}<br>
{{overline|ROMCS}}<br>
{{overline|IOREQ}}<br>
CLOCK<br>
D<sub>7</sub><br>
D<sub>6</sub><br>
D<sub>5</sub><br>
SOUND<br>
D<sub>4</sub><br>
KB<sub>4</sub><br>
D<sub>3</sub><br>
KB<sub>3</sub><br>
KB<sub>2</sub><br>
D<sub>2</sub><br>
D<sub>1</sub>
|}
</div>
=== 7C ULA ===
<div style="font-family:'Lucida Console', monospace">
{|
| style="text-align:right;" |
17M<br>
{{overline|CAS}}<br>
C<br>
DMA<sub>0</sub><br>
DMA<sub>1</sub><br>
DMA<sub>2</sub><br>
DMA<sub>3</sub><br>
DMA<sub>4</sub><br>
DMA<sub>5</sub><br>
DMA<sub>6</sub><br>
DMA<sub>7</sub><br>
VB<br>
(+5V) V<sub>CC-Logic</sub><br>
(+5V) V<sub>CC-IO</sub><br>
{{overline|RD}}<br>
{{overline|WR}}<br>
{{overline|INT}}<br>
{{overline|DRAMWE}}<br>
B<br>
G<br>
R<br>
BRIGHT<br>
SYNC<br>
D<sub>0</sub>
| style="border: 1px solid black" |
1&nbsp;°&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;48<br>
2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;47<br>
3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;46<br>
4&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;45<br>
5&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;44<br>
6&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;43<br>
7&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;42<br>
8&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;41<br>
9&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;40<br>
10&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;39<br>
11&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;38<br>
12&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;37<br>
13&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;36<br>
14&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;35<br>
15&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;34<br>
16&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;33<br>
17&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;32<br>
18&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;31<br>
19&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;30<br>
20&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;29<br>
21&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;28<br>
22&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;27<br>
23&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;26<br>
24&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;25
||
GND (0V)<br>
8.8M<br>
{{overline|8.8M}}<br>
{{overline|MREQ}}<br>
A<sub>15</sub><br>
A<sub>14</sub><br>
{{overline|RAS}}<br>
ROMS<br>
{{overline|IORQ}}<br>
PHICPU<br>
D<sub>7</sub><br>
D<sub>6</sub><br>
D<sub>5</sub><br>
MIC<br>
EAR<br>
D<sub>4</sub><br>
KB<sub>0</sub><br>
D<sub>3</sub><br>
KB<sub>1</sub><br>
KB<sub>2</sub><br>
D<sub>2</sub><br>
D<sub>1</sub><br>
KB<sub>3</sub><br>
KB<sub>4</sub>
|}
</div>
Retrieved from ‘https://sinclair.wiki.zxnet.co.uk/wiki/Special:MobileDiff/1606...1843’

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