VT02+ Registers

The VT03 is a famiclone with added capabilities. It uses "OneBus" instead of separate CPU and PPU buses, and supports a 4-bit color mode.

Registers

Program Bank 1, Video Bank 2 ($4100) > write

7  bit  0
---- ----
PPPP VVVV
|||| ||||
|||| ++++- Video Bank 2   (VA24, VA23, VA22, VA21)
++++------ Program Bank 1 (PA24, PA23, PA22, PA21)

Timer Interrupt Preload Times ($4101) > write

When TSYNEN is 0, this register sets "the number of AD12 switching high low". When TSYNEN is 1, this register sets "the number of HSYNC switching high low" instead. (See $410B.)

Load Timer Interrupt Value ($4102) > write

Writing any value to this register will set the timer's value and start counting.

Timer Interrupt Disable ($4103) > write

Writing any value to this register will disable the timer interrupt.

Timer Interrupt Enable ($4104) > write

Writing any value to this register will enable the timer interrupt.

V Bank 0 decode type, P Bank 0 decode type, Inter Char VRAM ($4105) > write

7  bit  0
---- ----
VPIx xxxx
|||| ||||
|||+-++++- unused
||+------- Internal VRAM as CHR RAM (0: disabled; 1: enabled)
|+-------- Program Bank 0 Decoding (see below table)
+--------- Video Bank 0 Decoding (see below table)

Program Bank 0 Decoding

PQ2EN ($410B)	COMR6	A[14:13] (CPU)	TPA20	TPA19	TPA18	TPA17	TPA16	TPA15	TPA14	TPA13
0	0		PQ07	PQ06	PQ05	PQ04	PQ03	PQ02	PQ01	PQ00
0	1		PQ17	PQ16	PQ15	PQ14	PQ13	PQ12	PQ11	PQ10
0	2		1	1	1	1	1	1	1	0
0	3		1	1	1	1	1	1	1	1
0	4		1	1	1	1	1	1	1	0
0	5		PQ17	PQ16	PQ15	PQ14	PQ13	PQ12	PQ11	PQ10
0	6		PQ07	PQ06	PQ05	PQ04	PQ03	PQ02	PQ01	PQ00
0	7		1	1	1	1	1	1	1	1
1	0		PQ07	PQ06	PQ05	PQ04	PQ03	PQ02	PQ01	PQ00
1	1		PQ17	PQ16	PQ15	PQ14	PQ13	PQ12	PQ11	PQ10
1	2		PQ27	PQ26	PQ25	PQ24	PQ23	PQ22	PQ21	PQ20
1	3		1	1	1	1	1	1	1	1
1	4		PQ27	PQ26	PQ25	PQ24	PQ23	PQ22	PQ21	PQ20
1	5		PQ17	PQ16	PQ15	PQ14	PQ13	PQ12	PQ11	PQ10
1	6		PQ07	PQ06	PQ05	PQ04	PQ03	PQ02	PQ01	PQ00
1	7		1	1	1	1	1	1	1	1

Video Bank 0 Decoding

COMR7	AD[12:10]	TVA17	TVA16	TVA15	TVA14	TVA13	TVA12	TVA11	TVA10
0,1,C,D		RV47	RV46	RV45	RV44	RV43	RV42	RV41	AD10
0	2,3,E,F		RV57	RV56	RV55	RV54	RV53	RV52	RV51	AD10
0	4,8		RV07	RV06	RV05	RV04	RV03	RV02	RV01	RV00
0	5,9		RV17	RV16	RV15	RV14	RV13	RV12	RV11	RV10
0	6,A		RV27	RV26	RV25	RV24	RV23	RV22	RV21	RV20
0	7,B		RV37	RV36	RV35	RV34	RV33	RV32	RV31	RV30

Horizontal/Vertical Scrolling Selector ($4106) > write

7  bit  0
---- ----
VPIx xxxx
|||| ||||
|||| |||+- H/V scrolling selector (0: Horizontal; 1: Vertical)
++++-+++-- unused

Program Bank 0 Register 0 ($4107) > write

7  bit  0
---- ----
PPPP PPPP
|||| ||||
|||| |||+- PQ00
|||| ||+-- PQ01
|||| |+--- PQ02
|||| +---- PQ03
|||+------ PQ04
||+------- PQ05
|+-------- PQ06
+--------- PQ07

Program Bank 0 Register 1 ($4108) > write

7  bit  0
---- ----
PPPP PPPP
|||| ||||
|||| |||+- PQ10
|||| ||+-- PQ11
|||| |+--- PQ12
|||| +---- PQ13
|||+------ PQ14
||+------- PQ15
|+-------- PQ16
+--------- PQ17

Program Bank 0 Register 2 ($4109) > write

7  bit  0
---- ----
PPPP PPPP
|||| ||||
|||| |||+- PQ20
|||| ||+-- PQ21
|||| |+--- PQ22
|||| +---- PQ23
|||+------ PQ24
||+------- PQ25
|+-------- PQ26
+--------- PQ27

Program Bank 0 Register 3 ($410A) > write

7  bit  0
---- ----
PPPP PPPP
|||| ||||
|||| |||+- PQ30
|||| ||+-- PQ31
|||| |+--- PQ32
|||| +---- PQ33
|||+------ PQ34
||+------- PQ35
|+-------- PQ36
+--------- PQ37

Timer interrupt clock selector, Program Bank 0 register 2 enable/disable, RS232 enable/disable, Bus output normal/tristate, Program Bank 0 selector ($410B) > write

7  bit  0
---- ----
TpRB XPPP
|||| ||||
|||| |+++- Program Bank 0 Selector
|||| +---- XRWB switch (0: Writes to $6000-$FFFF will not activate XRWB; 1: writes to $6000-$FFFF will activate XRWB)
|||+------ Bus output control (0: Normal bus output; 1: Tri-state bus)
||+------- RS232 (0: disabled; 1: enabled)
|+-------- Program Bank 0 Register 2 enable (0: disabled; 1: enabled)
+--------- Timer interrupt clock select (0: AD12; 1: HSYNC)

I/O Port Control ($410D) > write

7  bit  0
---- ----
DdCc BbAa
|||| ||||
|||| |||+- I/O port 0 mode (0: input; 1: output)
|||| ||+-- I/O port 0 enable (0: disabled; 1:enabled)
|||| |+--- I/O port 1 mode (0: input; 1: output)
|||| +---- I/O port 1 enable (0: disabled; 1:enabled)
|||+------ I/O port 2 mode (0: input; 1: output)
||+------- I/O port 2 enable (0: disabled; 1:enabled)
|+-------- I/O port 3 mode (0: input; 1: output)
+--------- I/O port 3 enable (0: disabled; 1:enabled)

• Bits d0-d3 must be set to $A if using flash memory in 16-bit mode.
• External SRAM is not available if using flash memory in 16-bit mode.

I/O Port Output Data, Ports 0 and 1 ($410E) <> read/write

7  bit  0
---- ----
DDDD dddd
|||| ||||
|||| ++++- I/O port 0 data (XVD3, XVD2, XVD1, XVD0)
++++------ I/O port 1 data (XVD7, XVD6, XVD5, XVD4)

I/O Port Output Data, Ports 2 and 3 ($410F) <> read/write

7  bit  0
---- ----
DDDD dddd
|||| ||||
|||| ++++- I/O port 2 data (XAD12, XAD11, XAD10, XRA10)
++++------ I/O port 3 data (XVRW, VXOEB, XRCB, XRC)

RS232 Timer

"In PAL system, CK21M is 26.601712MHz, in NTSC system is 21.47727MHz. RS232T=#4115,#4114 data. Baud rate will be CK21M/((RS232T+2)*2). For example, In PAL system, the baud rate 9600, RS232T=0567."

RS232 Timer Low Byte ($4114) > write

Write the low byte of the RS232 timer.

RS232 Timer High Byte ($4115) > write

Write the high byte of the RS232 timer.

RS232 Register ($4119) > write

7  bit  0
---- ----
xxBx xxxT
|||| ||||
|||| |||+- TX bit 8
|||+-+++-- unused
||+------- Bit 8 enable (0: 10 bits mode including start, end bits, and bit 7-0 data; 1: 11 bits mode including start, end bits, bit 8 and bit7-0 data)
++-------- unused

RS232 Flags ($4119) < read

7  bit  0
---- ----
rsTV VxER
|||| ||||
|||| |||+- RX bit 8
|||| ||+-- RERRF (If 1, receiving error occurred)
|||| |+--- unused
|||+-+---- Output pins: TV system selector (XF5OR6 (50/60Hz?), XPORN (PAL/NTSC?))
||+------- RINGF (If 1, currently receiving data)
|+-------- TIFLAG (If 1, completed sending data)
+--------- RIFLAG (If 1, completed receiving data)

RS232 TX data ($411A) > write

Write RS232 data (bits 7-0).

RS232 RX data ($411B) < read

Read RS232 data (bits 7-0).