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Gate Array

972 bytes added, Sunday at 22:07
/* External links */
[[File:Amstrad 40007 Gate Array.png|right|thumb|Amstrad 40007 Gate Array]]
[[File:Amstrad 40010 Gate Array.png|right|thumb|Amstrad 40010 Gate Array]]
 
Also designated as Video Gate Array (VGA, not to be confused with the IBM PC compatible graphic card spec).
*If the interrupts were authorized at the time of the request, then bit5 of R52 is cleared (but R52 was reset to 0 anyway) and the interrupt takes place
*If interrupts are not authorized, then the R52 counter continues to increment and the interrupt remains armed (the Gate Array then maintains its INT signal). When interrupts are enabled (using the EI instruction), bit5 of R52 is cleared and the interrupt takes place. This happens only '''after the instruction that follows EI''' as this Z80 instruction has a 1-instruction delay.
 
[https://shaker.logonsystem.eu/ACCC1.8-EN.pdf Source]
Note: On Amstrad Plus, the interrupt management system is seriously beefed up. See the [[ASIC]] wiki page.
On a CPC monitor, the CSYNC is rendered in "absolute black". It is darker than the palette colour black output by the Gate Array. The electron beam is basically turned off. Turning up the brightness level won't make it any brighter.
[https://shaker.logonsystem.eu/ACCC1.8-EN.pdf Source]
<br>
<br>
=== Amstrad Palette sorted by Firmware Colour Names Numbers ===
<gallery>Cpc 6128 master The firmware colour chat.jpg|Master colour chartCpc 6128 farbtabelle.jpg|FarbtabelleCpc 6128 palette des couleurs.jpg|Palette des couleursCpc 6128 tabla de colores.jpg|Tabla de colores</gallery> <br> === Palette is sorted by Hardware Colour Numbers ===luminance value.
{| class="wikitable"
|-
!Hardware Number|-
!Firmware Number
!Hardware Number
!Colour Name
!R %
!G %
!ASIC
!Colour
!Colour Name
!German Name
!Spanish Name
|-
| 0 (40h) || 13 54h || 50Black || 50 0|| 50 0|| 0|| #666000|| bgcolor="#808080000000" | || White || Weiß || Blanco
|-
| 1 (41h) || 44h (13or 50h) || 50Blue || 50 0|| 0|| 50|| #666006|| bgcolor="#808080000080" | || White || Weiß || Blanco
|-
| 2 (42h) || 19 55h ||Bright Blue || 0||100 0|| 50100|| #0F600F|| bgcolor="#00ff800000ff" | || Sea Green || Seegrün || Verde marino
|-
| 3 (43h) || 25 5Ch ||100Red ||10050|| 50 0|| 0|| #FF6600|| bgcolor="#ffff80800000" | || Pastel Yellow || Pastellgelb || Amarillo pastel
|-
| 4 (44h) || 1 58h || 0Magenta || 50|| 0|| 50|| #006606|| bgcolor="#000080800080" | || Blue || Blau || Azul
|-
| 5 (45h) || 7 5Dh ||100Mauve || 50|| 0|| 50100|| #F0660F|| bgcolor="#ff00808000ff" | || Purple || Purpur || Púrpura
|-
| 6 (46h) || 10 4Ch ||Bright Red ||100|| 0|| 50|| 50 0|| #066F00|| bgcolor="#008080ff0000" | || Cyan || Blaugrün || Ciano
|-
| 7 || 45h (47hor 48h) || 16 Purple ||100|| 50 0|| 50|| #F66F06|| bgcolor="#ff8080ff0080" | || Pink || Rosa || Rosa
|-
| 8 (48h) || (7) 4Dh ||Bright Magenta ||100|| 0|| 50100|| #F06F0F|| bgcolor="#ff0080ff00ff" | || Purple || Purpur || Púrpura
|-
| 9 (49h) || (25) 56h ||100Green ||100 0|| 50|| 0|| #FF6060|| bgcolor="#ffff80008000" | || Pastel Yellow || Pastellgelb || Amarillo pastel
|-
| 10 (4Ah) || 24 46h ||100||100Cyan || 0|| 50|| 50|| #FF0066|| bgcolor="#ffff00008080" | || Bright Yellow || Hellgelb || Amarillo brillante
|-
| 11 (4Bh) || 26 57h ||100Sky Blue ||100 0|| 50||100|| #FFF06F|| bgcolor="#ffffff0080ff" | || Bright White || Leuchtendweiß || Blanco brillante
|-
| 12 (4Ch) || 6 5Eh ||100Yellow || 050|| 50|| 0|| #F00660|| bgcolor="#ff0000808000" | || Bright Red || Hellrot || Rojo brillante
|-
| 13 || 40h (4Dhor 41h) || 8 White ||10050|| 050||10050|| #F0F666|| bgcolor="#ff00ff808080" | || Bright Magenta|| helles Magenta || Magenta brillante
|-
| 14 (4Eh) || 15 5Fh ||100Pastel Blue || 50|| 050||100|| #F6066F|| bgcolor="#ff80008080ff" | || Orange || Orange || Naranja
|-
| 15 (4Fh) || 17 4Eh ||Orange ||100|| 50||100 0|| #F6FF60|| bgcolor="#ff80ffff8000" | || Pastel Magenta|| Pastell-magenta || Magenta pastel
|-
| 16 (50h) || (1) 47h || 0Pink || 0100|| 50|| 50|| #006F66|| bgcolor="#000080ff8080" | || Blue || Blau || Azul
|-
| 17 (51h) || (19) 4Fh || 0Pastel Magenta ||100|| 50||100|| #0F6F6F|| bgcolor="#00ff80ff80ff" | || Sea Green || Seegrün || Verde marino
|-
| 18 (|| 52h) || 18 Bright Green || 0||100|| 0|| #0F0|| bgcolor="#00ff00" | || Bright Green || Hellgrün || Verde brillante
|-
| 19 || 42h (53hor 51h) || 20 Sea Green || 0||100||10050|| #0FF0F6|| bgcolor="#00ffff00ff80" | || Bright Cyan || helles Blaugrün || Ciano brillante
|-
| 20 (54h) || 0 53h ||Bright Cyan || 0|| 0100|| 0100|| #0000FF|| bgcolor="#00000000ffff" | || Black || Schwarz || Negro
|-
| 21 (55h) || 2 5Ah || 0Lime || 050||100|| 0|| #00F6F0|| bgcolor="#0000ff80ff00" | || Bright Blue || Hellblau || Azul brillante
|-
| 22 (56h) || 9 59h || 0Pastel Green || 50|| 0100|| 50|| #0606F6|| bgcolor="#00800080ff80" | || Green || Grün || Verde
|-
| 23 (57h) || 11 5Bh || 0Pastel Cyan || 50||100||100|| #06F6FF|| bgcolor="#0080ff80ffff" | || Sky Blue || Himmelblau || Azul cielo
|-
| 24 (58h) || 4 4Ah || 50Bright Yellow ||100||100|| 0|| 50|| #606FF0|| bgcolor="#800080ffff00" | || Magenta || Magenta || Magenta
|-
| 25 || 43h (59hor 49h) || 22 Pastel Yellow || 50100||100|| 50|| #6F6FF6|| bgcolor="#80ff80ffff80" | || Pastel Green || Pastellgrün || Verde pastel
|-
| 26 (5Ah) || 21 || 50||100|| 0|| #6F0|| bgcolor="#80ff00" | || Lime 4Bh || Limonengrün || Verde lima|-| 27 (5Bh) || 23 Bright White || 50||100||100|| #6FF|| bgcolor="#80ffff" | || Pastel Cyan || Pastell-blaugrün|| Ciano pastel|-| 28 (5Ch) || 3 || 50|| 0|| 0|| #600|| bgcolor="#800000" | || Red || Rot || Rojo|-| 29 (5Dh) || 5 || 50|| 0||100|| #60FFFF|| bgcolor="#8000ffffffff" | || Mauve || Hellviolett || Malva|-| 30 (5Eh) || 12 || 50|| 50|| 0|| #660|| bgcolor="#808000" | || Yellow || Gelb || Amarillo|-| 31 (5Fh) || 14 || 50|| 50||100|| #66F|| bgcolor="#8080ff" | || Pastel Blue || Pastellblau || Azul pastel
|}
 
Note: We can observe that the official Amstrad names of some colours are a bit silly: "red" is in fact brown, "yellow" is in fact khaki and "white" is in fact grey.
<br>
=== Intensities Amstrad Colour Names ===
The 0%, 50%, and 100% values in the above tables are "should-be" values. However, the real hardware doesn't exactly match that intensities. The actual intensities depend on the luminance mixing (R,G,B tied together via resistors), on chipset (classic CPC, or newer ASIC ones), and on the load applied by external hardware (Monitor, or TV set).<gallery>On an actual Amstrad CPC, the half-intensity Cpc 6128 master colour signal is measured to be closer to 40% rather than the expected 50%chat. This was verified by Grim and independently confirmed by Nocash. [https://www.grimware.org/doku.php/documentations/devices/gatearray#inkr Source]* [[CPC Palette]] - some more details This explains why the Amstrad engineers used the following values to adapt the old jpg|Master colour palette to the new 12-bit palette on the Amstrad Plus:chart* 0% became #0Cpc 6128 farbtabelle.jpg|Farbtabelle* 50% became #6. They specifically chose #6 for the 50% value instead of the expected #7 or #8, to better match the real Amstrad CPC Cpc 6128 palettedes couleurs.jpg|Palette des couleurs* 100% became #FCpc 6128 tabla de colores.jpg|Tabla de colores</gallery>
<br>
=== Palette sorted by Firmware Hardware Colour Numbers === The firmware colour palette is sorted by luminance value.
{| class="wikitable"
|-
|-!Hardware Number
!Firmware Number
!Hardware Number
!Colour Name
!R %
!G %
!ASIC
!Colour
!Colour Name
!German Name
!French Name
!Spanish Name
|-
| 0(40h) || 54h 13 ||Black 50|| 050|| 0|| 050|| #000666||bgcolor="#000000808080"||| White || Weiß || Blanc || Blanco
|-
| 1(41h) || 44h (or 50h13) ||Blue 50|| 0|| 050|| 50|| #006666||bgcolor="#000080808080"||| White || Weiß || Blanc || Blanco
|-
| 2(42h) || 55h ||Bright Blue 19 || 0|| 0100||10050|| #00F0F6||bgcolor="#0000ff00ff80"||| Sea Green || Seegrün || Vert marin || Verde marino
|-
| 3(43h) || 5Ch 25 ||Red 100|| 50100|| 0|| 050|| #600FF6||bgcolor="#800000ffff80"||| Pastel Yellow || Pastellgelb || Jaune pastel || Amarillo pastel
|-
| 4(44h) || 58h 1 ||Magenta || 50 0|| 0|| 50|| #606006||bgcolor="#800080000080"||| Blue || Blau || Bleu || Azul
|-
| 5(45h) || 5Dh 7 ||Mauve || 50100|| 0||10050|| #60FF06||bgcolor="#8000ffff0080"||| Purple || Purpur || Pourpre || Púrpura
|-
| 6(46h) || 4Ch ||Bright Red ||10010 || 0|| 050|| 50|| #F00066||bgcolor="#ff0000008080"||| Cyan || Blaugrün || Turquoise || Ciano
|-
| 7|| 45h (or 48h47h) ||Purple 16 ||100|| 050|| 50|| #F06F66||bgcolor="#ff0080ff8080"||| Pink || Rosa || Rose || Rosa
|-
| 8(48h) || 4Dh ||Bright Magenta (7) ||100|| 0||10050|| #F0FF06||bgcolor="#ff00ffff0080"||| Purple || Purpur || Pourpre || Púrpura
|-
| 9(49h) || 56h (25) ||Green 100|| 0100|| 50|| 0|| #060FF6||bgcolor="#008000ffff80"||| Pastel Yellow || Pastellgelb || Jaune pastel || Amarillo pastel
|-
|10(4Ah) || 46h 24 ||Cyan 100||100|| 0|| 50|| 50|| #066FF0||bgcolor="#008080ffff00"||| Bright Yellow || Hellgelb || Jaune vif || Amarillo brillante
|-
|11(4Bh) || 57h 26 ||Sky Blue 100|| 0|| 50100||100|| #06FFFF||bgcolor="#0080ffffffff"||| Bright White || Leuchtendweiß || Blanc brillant || Blanco brillante
|-
|12(4Ch) || 5Eh 6 ||Yellow 100|| 50|| 50 0|| 0|| #660F00||bgcolor="#808000ff0000"||| Bright Red || Hellrot || Rouge vif || Rojo brillante
|-
|13|| 40h (or 41h4Dh) ||White 8 || 50100|| 50 0|| 50100||#666F0F||bgcolor="#808080ff00ff"||| Bright Magenta|| helles Magenta || Magenta vif || Magenta brillante
|-
|14(4Eh) || 5Fh 15 ||Pastel Blue 100|| 50|| 50||100 0|| #66FF60||bgcolor="#8080ffff8000"||| Orange || Orange || Orange || Naranja
|-
|15(4Fh) || 4Eh ||Orange 17 ||100|| 50|| 0100|| #F60F6F|| bgcolor="#ff8000ff80ff"||| Pastel Magenta|| Pastell-magenta || Magenta pastel || Magenta pastel
|-
|16(50h) || 47h (1) ||Pink 0||100|| 50 0|| 50|| #F66006||bgcolor="#ff8080000080"||| Blue || Blau || Bleu || Azul
|-
|17(51h) || 4Fh (19) ||Pastel Magenta 0||100|| 50||100|| #F6F0F6||bgcolor="#ff80ff00ff80"||| Sea Green || Seegrün || Vert marin || Verde marino
|-
|18|| (52h ) ||Bright Green 18 || 0||100|| 0|| #0F0||bgcolor="#00ff00"||| Bright Green || Hellgrün || Vert vif || Verde brillante
|-
|19|| 42h (or 51h53h) ||Sea Green 20 || 0||100|| 50100|| #0F60FF||bgcolor="#00ff8000ffff"||| Bright Cyan || helles Blaugrün || Turquoise vif || Ciano brillante
|-
|20(54h) || 53h ||Bright Cyan 0 || 0||100 0||100 0|| #0FF000||bgcolor="#00ffff000000"||| Black || Schwarz || Noir || Negro
|-
|21(55h) || 5Ah 2 ||Lime 0|| 50 0||100|| 0|| #6F000F||bgcolor="#80ff000000ff"||| Bright Blue || Hellblau || Bleu vif || Azul brillante
|-
|22(56h) || 59h 9 ||Pastel Green 0|| 50||100|| 50 0|| #6F6060||bgcolor="#80ff80008000"||| Green || Grün || Vert || Verde
|-
|23(57h) || 5Bh 11 ||Pastel Cyan 0|| 50||100||100|| #6FF06F||bgcolor="#80ffff0080ff"||| Sky Blue || Himmelblau || Bleu ciel || Azul cielo
|-
|24(58h) || 4Ah 4 ||Bright Yellow ||100||10050|| 0|| 50|| #FF0606||bgcolor="#ffff00800080"||| Magenta || Magenta || Magenta || Magenta
|-
|25(59h) || 22 || 50||100|| 50|| #6F6|| bgcolor="#80ff80" | || Pastel Green || Pastellgrün || Vert pastel || Verde pastel|-| 43h 26 (or 49h5Ah) ||Pastel Yellow 21 || 50||100|| 0|| #6F0|| bgcolor="#80ff00" | || Lime || Limonengrün || Vert citron || Verde lima|-| 27 (5Bh) || 23 || 50||100||100|| #6FF|| bgcolor="#80ffff" | || Pastel Cyan || Pastell-blaugrün|| Turquoise pastel|| Ciano pastel|-| 28 (5Ch) || 3 || 50|| 0|| 0||#FF6600||bgcolor="#ffff80800000"||| Red || Rot || Rouge || Rojo
|-
|2629 (5Dh) || 4Bh 5 ||Bright White 50||100 0||100|| #60F|| bgcolor="#8000ff" | || Mauve || Hellviolett || Mauve || Malva|-| 30 (5Eh) || 12 || 50|| 50|| 0|| #660|| bgcolor="#808000" | || Yellow || Gelb || Jaune || Amarillo|-| 31 (5Fh) || 14 || 50|| 50||100|| #FFF66F||bgcolor="#ffffff8080ff"||| Pastel Blue || Pastellblau || Bleu pastel || Azul pastel
|}
 
Note: We can observe that the official Amstrad names of some colours are a bit silly: "red" is in fact brown, "yellow" is in fact khaki and "white" is in fact grey.
<br>
=== Green Screen Colours Intensities ===
On a green screenThe 0%, where all colours 50%, and 100% values in the above tables are shades of unsaturated green"should-be" values. However, the colours real hardware doesn't exactly match that intensities. The actual intensities depend on the luminance mixing (in BASIC coloursR,G,B tied together via resistors) are in order of increasing intensity. Black is darkest green, white is brightest greenon chipset (classic CPC, or newer ASIC ones), and colour 13 is a medium greenon the load applied by external hardware (Monitor, or TV set).
The luminance (Y) On an actual Amstrad CPC, the half-intensity colour signal is not exactly correlated measured to be closer to 40% rather than the actual luminance of colour images broadcast in RGBexpected 50%. This was verified by [[Grim]] and independently confirmed by [[Nocash]]. [https://www.grimware. We have other valuesorg/doku.php/documentations/devices/gatearray#inkr Source]* [[CPC Palette]] - some more details
This explains why the Amstrad preferred engineers used the following values to propose a completely different image system, not comparable to a conversion to monochrome, which would have limited adapt the number of brightness levels old colour palette to 21 (for example, colours 9 and 6 would have had the same luminance).new 12-bit palette on the Amstrad Plus:* 0% became #0* 50% became #6. They opted specifically chose #6 for a table the 50% value instead of 27 linear brightness steps. They assigned values of 1 (1kΩ) for bluethe expected #7 or #8, 3 (3.3kΩ) for red, and 9 (10kΩ) for greento better match the real Amstrad CPC palette.* 100% became #F
<br>
=== To calculate the luminance value Green Screen Colours ===
'''Red''' On a green screen, where all colours are shades of unsaturated green, the firmware colours are in order of increasing intensity. Black is darkest green, bright white is brightest green, and firmware colour 13 is a medium green.
0% =&gt; do The luminance (Y) is not add anything exactly correlated to the actual luminance of colour images broadcast in RGB. Amstrad preferred to propose a completely different image system, not comparable to a conversion to monochrome, which would have limited the number of brightness levels to 21 (for example, colours 9 and 6 would have had the same luminance).
50% =&gt; add They opted for a table of 27 linear brightness steps. They assigned values of 1 (1kΩ) for blue, 3 (3.3kΩ) for red, and 9 (10kΩ) for green.
100% =&gt; add 6 === To calculate the luminance value ====
'''GreenRed'''
*0% =&gt; do not add anything *50% =&gt; add 3 *100% =&gt; add 6
50% =&gt; add 9 '''Green'''
*0% =&gt; do not add anything *50% =&gt; add 9 *100% =&gt; add 18
'''Blue'''
*0% =&gt; do not add anything  *50% =&gt; add 1  *100% =&gt; add 2
<br>
== External links ==
*[https://bread80.com/2021/06/03/understanding-the-amstrad-cpc-video-ram-and-gate-array-subsystem/ Electronic signals analysis of the Gate Array by Bread80]
* [https://shaker.logonsystem.eu/ACCC1.8-EN.pdf Gate Array documentation in Amstrad CRTC Compendium]
* [https://www.grimware.org/doku.php/documentations/devices/gatearray Gate Array documentation from Grimware]
* [http://quasar.cpcscene.net/doku.php?id=assem:gate_array Quasar Gate Array documentation (in french)]
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