Page 235 | ZX Spectrum Next User Manual, 3rd Edition

Page 235

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[?]

Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	D
Issue 2 keyboard	■	■	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	•	Enable Issue 2 keyboard	■	0
NextSound			colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	•	colour: pink	Enable Multiple PSGs*	■	0
Timex Video Port Control	■	■	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	•	colour: pink	colour: pink	Enable read of Port FFh (Timex)**	■	0
DACs Control			colour: pink	colour: pink	colour: pink	colour: pink	•	colour: pink	colour: pink	colour: pink	Enable DACs (A-B-C-D)	■	0
Internal Speaker Control	■	■	colour: pink	colour: pink	colour: pink	•	colour: pink	colour: pink	colour: pink	colour: pink	Enable Internal Speaker	■	1
PSG Stereo Mode Control	■	■	colour: pink	colour: pink	0	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Select ABC	■	0
PSG Stereo Mode Control	■	■	colour: pink	colour: pink	1	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Select ACB	■	0
Contention Control	■	■	colour: pink	•	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Disable RAM and Port Contention		0
128K Banking Unlock Control	■	■	•	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Unlock Port 7FFDh D5 (Unlocked = 1)		0

* Currently selected PSG is frozen when disabled
** Enabling Timex Video Port read hides the floating bus on FFh

NextREG 09 (09h) – Peripheral 4 Settings

Group Name	R	W	Data Bits								Description	H	D
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	D
Scanline Strength	■	■	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	0	0	Scanlines off
			colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	0	1	Scanlines at 50%
			colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	1	0	Scanlines at 25%
			colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	1	1	Scanlines at 12.5%
HDMI audio output Control	■	■	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	•	colour: pink	colour: pink	HDMI audio mute	■	0
divMMC mapRAM bit Control	■	■	colour: pink	colour: pink	colour: pink	colour: pink	•	colour: pink	colour: pink	colour: pink	Reset bit 6 port E3h (Read is always 0)
Sprite Lockstep Control	■	■	colour: pink	colour: pink	colour: pink	•	colour: pink	colour: pink	colour: pink	colour: pink	Enable Sprite ID Lockstep		0
PSG 0 Mono Mode Control	■	■	colour: pink	colour: pink	•	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Enable Mono	■	0
PSG 1 Mono Mode Control	■	■	colour: pink	•	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Enable Mono	■	0
PSG 2 Mono Mode Control	■	■	•	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Enable Mono	■	0

In Sprite Lockstep, NextREG 52 (34h) and Port 12347 (303Bh) are in Lockstep

NextREG 10 (0Ah) – Peripheral 5 Settings

Group Name	R	W	Data Bits								Description	H	D
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	D
Mouse resolution Control	■	■	colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	0	0	Low DPI	■
			colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	0	1	Default
			colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	1	0	Medium DPI
			colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	1	1	High DPI
Reserved	■	■	colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green 0	colour: pink	colour: pink	Reserved, must be 0		0
Mouse button swap Control	■	■	colour: pink	colour: pink	colour: dark green	colour: pink	•	colour: dark green	colour: pink	colour: pink	Reverses (swaps) L & R mouse buttons	■	0
divMMC Automap Control	■	■	colour: pink	colour: pink	colour: dark green	•	colour: pink	colour: dark green	colour: pink	colour: pink	Enables divMMC Automap	■	0
Reserved	■	■	colour: pink	colour: pink	colour: dark green 0	colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	Reserved, must be 0	■	0
Multiface Type	■	■	0	0	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	Multiface +3¹	♦	0
			0	1	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	Multiface 128 v87.2²
			1	0	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	Multiface 128 v87.12³
			1	1	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: pink	colour: pink	Multiface 1⁴

¹ Enables port 3Fh, disables port BFh
² Enables port BFh, disables port 3Fh
³ Enables port 9Fh, disables port 1Fh
⁴ Enables port 9Fh, disables port 1Fh

NextREG 11 (0Bh) – Joystick Port Mode Selection

Group Name	R	W	Data Bits								Description	H	D
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	D
Parameter (Bit Bang)	■	■	colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: dark green	colour: dark green	•	Copied to pin 7 of the active connector¹		1
Parameter (Clock)			colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: dark green	colour: dark green	0	Hold high when clock becomes high
Parameter (Clock)			colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: dark green	colour: dark green	1	Run²
Parameter (UART)			colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: dark green	colour: dark green	0	Redirect ESP UART_0 to connector³
Parameter (UART)			colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: dark green	colour: dark green	1	Redirect Pi UART_1 to connector³
Reserved	■	■	colour: pink	colour: dark green	colour: pink	colour: pink	colour: dark green 0	colour: dark green 0	colour: dark green 0	colour: pink	Reserved, must be 0		0
I/OMode Control	■	■	colour: pink	colour: dark green	0	0	colour: dark green	colour: dark green	colour: dark green	colour: pink	Bit Bang		0
			colour: pink	colour: dark green	0	1	colour: dark green	colour: dark green	colour: dark green	colour: pink	Clock
			colour: pink	colour: dark green	1	0	colour: dark green	colour: dark green	colour: dark green	colour: pink	UART on left joystick port
			colour: pink	colour: dark green	1	1	colour: dark green	colour: dark green	colour: dark green	colour: pink	UART on right joystick port
Reserved	■	■	colour: pink	colour: dark green 0	colour: pink	colour: pink	colour: dark green	colour: dark green	colour: dark green	colour: pink	Reserved, must be 0		0
Joystick Port Mode Selection	■	■	0	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: dark green	colour: dark green	colour: pink	Joysticks Enabled		0
Joystick Port Mode Selection	■	■	1	colour: dark green	colour: pink	colour: pink	colour: dark green	colour: dark green	colour: dark green	colour: pink	I/O Mode Enabled		0

¹ The state of output pin 7 is stored internally in a register and is retained across changing modes and while I/O is disabled
² CTC Ch. 3 is currently used to drive pin 7 in clock mode. Frequency= f_CTC3 ÷2
³ Tx out on pin 7, Rx in from pin 9, CTS_n in from pin 6. CTS_n is only active if the selected UART is in hardware flow control mode
* While in I/O mode, keyboard joystick types (Sinclair, Cursor etc) produce no readings but the current state of pins can still be read via the Kempston ports. When leaving I/O mode, joystick operation resumes after approximately 64 scanlines have passed

NextREG 14 (0Eh) – Core Version (Sub minor number)

Group Name	R	W	Data Bits								Description	H	D
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	D
Sub Minor Number	■		•	•	•	•	•	•	•	•	Core Sub Minor Version Number

See NextREG 01 (01h) for Major and Minor Core Version

NextREG 15 (0Fh) – Board ID

Group Name	R	W	Data Bits								Description	H	D
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	D
Board Revision	■		colour: dark green	colour: dark green	colour: dark green	colour: dark green	0	0	0	0	ZX Spectrum Next Issue 2¹
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	0	0	0	1	ZX Spectrum Next Issue 3¹
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	0	0	1	0	ZX Spectrum Next Issue 4²
Reserved	■		colour: dark green 0	colour: dark green 0	colour: dark green 0	colour: dark green 0	colour: pink	colour: pink	colour: pink	colour: pink	Reserved

¹ XC6SLX16-2FTG256, 128 Mbit W25Q128JV Flash, 24-bit SPI, 64K*8 Core size
² XC7A15T-1CSG324, 256 Mbit MX25L25645G Flash, 32-bit SPI, 64K*34 Core size

[?]

Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
NMI Button State Flag	■		colour: dark green	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	•	NMI Button Pressed		[?]
Drive Button State Flag	■		colour: dark green	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	•	colour: pink	Drive Button Pressed		[?]
	■		colour: dark green	•	•	•	•	•	colour: pink	colour: pink	Core ID (0-31)		[?]
Reserved	■		colour: dark green 0	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Reserved, must be 0		[?]
Core ID		■	colour: pink	colour: dark green	colour: dark green	•	•	•	•	•	Core ID (0-31)	♦	[?]
Reserved		■	colour: pink	colour: dark green 0	colour: dark green 0	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Reserved, must be 0		[?]
Start Core		■	•	colour: dark green	colour: dark green	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Reboot FPGA using selected core		[?]

Core ID with D0 through D4 can be set in configuration mode only

NextREG 17 (11h) – Video Timing

Group Name	R	W	Data Bits								Description	H	[?]
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
VGA Timing	■	■	colour: dark green	colour: dark green	colour: dark green	colour: dark green	colour: dark green	0	0	0	Base VGA timing, clk28 = 28000000	♦	[?]
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	colour: dark green	0	0	1	VGA setting 1, clk28 = 28571429
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	colour: dark green	0	1	0	VGA setting 2, clk28 = 29464286
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	colour: dark green	0	1	1	VGA setting 3, clk28 = 30000000
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	colour: dark green	1	0	0	VGA setting 4, clk28 = 31000000
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	colour: dark green	1	0	1	VGA setting 5, clk28 = 32000000
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	colour: dark green	1	1	0	VGA setting 6, clk28 = 33000000
			colour: dark green	colour: dark green	colour: dark green	colour: dark green	colour: dark green	1	1	1	Digital, clk28 =27000000
Reserved	■	■	colour: dark green 0	colour: dark green 0	colour: dark green 0	colour: dark green 0	colour: dark green 0	colour: pink	colour: pink	colour: pink	Reserved, must be 0		[?]

50 Hz / 60 Hz depends on NextREG 05 (05h):D2
NextREG writable in configuration mode only

NextREG 18 (12h) – Layer 2 Active RAM Bank

Group Name	R	W	Data Bits								Description	H	[?]
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
Layer 2 Active RAM Bank	■	■	colour: dark green	•	•	•	•	•	•	•	Starting 16K RAM Bank		[?]
Reserved	■	■	colour: dark green 0	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Reserved, must be 0		[?]

Soft reset resets the default to 8. NextZXOS changes that to 9

NextREG 19 (13h) – Layer 2 Shadow RAM Bank

Group Name	R	W	Data Bits								Description	H	[?]
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
Layer 2 Shadow RAM Bank	■	■	colour: dark green	•	•	•	•	•	•	•	Starting 16K RAM Bank		[?]
Reserved	■	■	colour: dark green 0	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Reserved, must be 0		[?]

Soft reset resets the default to 11. NextZXOS changes that to 12

NextREG 20 (14h) – Global Transparency Colour

Group Name	R	W	Data Bits								Description	H	[?]
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
Global Transparency Mask	■	■	•	•	•	•	•	•	•	•	8-bit colour value		[?]

Default value upon soft reset is E3h (227)
This value is 8-bit; the transparency colour is compared against the MSB of the actual 9-bi[?] colour; as such, two colours (with either value of B₀) are made transparent
This setting only applies to Layer 2, Layer 0 and Layer 1. Sprites use NextREG 75 (4Bh) and Layer 3 uses NextREG 76 (4Ch) for transparency except in text mode

NextREG 21 (15h) – Sprite and Layer System Setup

Group Name	R	W	Data Bits								Description	H	[?]
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
Sprite Engine Control	■	■	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	•	Enable Sprites		[?]
Sprite Extended Area Control	■	■	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	•	colour: pink	Enable Sprites over border		[?]
Set Layer Priority	■	■	colour: pink	colour: pink	colour: pink	0	0	0	colour: pink	colour: pink	S L U		[?]
			colour: pink	colour: pink	colour: pink	0	0	1	colour: pink	colour: pink	L S U
			colour: pink	colour: pink	colour: pink	0	1	0	colour: pink	colour: pink	S U L
			colour: pink	colour: pink	colour: pink	0	1	1	colour: pink	colour: pink	L U S
			colour: pink	colour: pink	colour: pink	1	0	0	colour: pink	colour: pink	U S L
			colour: pink	colour: pink	colour: pink	1	0	1	colour: pink	colour: pink	U L S
			colour: pink	colour: pink	colour: pink	1	1	0	colour: pink	colour: pink	(U\|T)S(T\|U)(B+L) combined¹
			colour: pink	colour: pink	colour: pink	1	1	1	colour: pink	colour: pink	(U\|T)S(T\|U)(B+L) combined¹
Sprite Border Clipping	■	■	colour: pink	colour: pink	•	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Enable Sprite Clipping in over border mode		[?]
Sprite Priority	■	■	colour: pink	0	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Sprite 127 on top		[?]
Sprite Priority	■	■	colour: pink	1	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Sprite 0 on top		[?]
LoRes Control	■	■	•	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	colour: pink	Enable LoRes		[?]

1 Colours Clamped to [0,7]
ULA means all ULA modes: Layers 0 and all Layer 1 types. Value upon soft reset is 000

NextREG 22 (16h) – Layer 2 Horizontal Scroll Control LSB

Group Name	R	W	Data Bits								Description	H	[?]
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
X Offset LSB	■	■	•	•	•	•	•	•	•	•	8-bit value of X Offset LSB (0 – 511)		[?]

MSB is in NextREG 113 (71h)

NextREG 23 (17h) – Layer 2 Vertical Scroll Control

Group Name	R	W	Data Bits								Description	H	[?]
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
Y Offset	■	■	•	•	•	•	•	•	•	•	8-bit value of Y Offset		[?]

NextREG 24 (18h) – Layer 2 Clip Window Definition

Group Name	R	W	Data Bits								Description	H	[?]
Group Name	R	W	7	6	5	4	3	2	1	0	Description	H	[?]
Coordinate (X_beg,X_end,Y_beg,Y_end)	■	■	•	•	•	•	•	•	•	•	8-bit value of X_beg,X_end,Y_beg,Y_end coordinate¹		[?]

¹ 1^st Write X_beg position – *Resets to 0
2^nd Write X_end position – *Resets to 255
3^rd Write Y_beg position – *Resets to 0
4^rh Write Y_end position – *Resets to 191
Reads do not advance the clip coordinate – Use NR 28 (1Ch) to find out the current clip coordinate or to set the clip coordinate to X_beg. The X coordinates are internally doubled fo[?] higher resolution modes. This means that X_end =159 covers the full 320 resolution.

ZX Spectrum Next User Manual, 3rd Edition (ISBN 978-1-5272-5496-1), written and illustrated by Phoebus R. Dokos. Copyright © 2020-2024 Phoebus Dokos / SpecNext Ltd. Licensed under CC BY-NC-SA 4.0. This is a transcription and can contain errors; check any doubt against the printed page.