PiPicoMite01

Features

• Raspberry Pi Pico
  • All pins brought to header
  • Pin marking on rear
• VGA (1:2:1 - R:G:B)
• PS/2 Keyboard
  • 5V to keyboard with voltage translator
• SD Card
  • Full size card
  • Up to 32GB
• Stereo audio
  • 3.5mm jack
• 16-bit GPIO
  • MCP23017 port expander
  • I2C1
  • 2x20 0.1" pitch header
  • Jumper selectable terminators
• Power options
  • 5V power input via USB B or 0.1" pitch header
  • 3.3V output header
• 120mmx70mm outline
• (4) 6-32 Mounting holes

BASIC Interpreter

The BASIC interpreter is full featured with double precision floating point, 64-bit integers and string variables, long variable names, arrays of floats, integers or strings with multiple dimensions, extensive string handling and user defined subroutines and functions. Typically it will execute a program up to 100,000 lines per second. MMBasic allows the embedding of compiled C programs for high performance functions and the running program can be protected from being listed or modified by a PIN number.

Support for all Raspberry Pi Pico input/output pins. These can be independently configured as digital input or output, analog input, frequency or period measurement and counting. Within MMBasic the I/O pins can be dynamically configured as inputs or outputs with or without pullups or pulldowns.

MMBasic commands will generate pulses and can be used to transfer data in parallel. Interrupts can be used to notify when an input pin has changed state. PWM outputs can be used to create various sounds, control servos or generate computer controlled voltages for driving equipment that uses an analogue input (eg, motor controllers). In addition, pins that are not exposed on the Raspberry Pi Pico can be accessed using MMBasic allowing it to be used on other modules that use the RP2040 processor.

TFT LCD display panels using SPI based interfaces are supported allowing the BASIC program to display text and draw lines, circles, boxes, etc in 65,535 colours. Resistive touch controllers on these panels are also supported allowing them to be used as sophisticated input devices. These LCD panels typically cost US$7 and provide a low cost, high tech graphical user interface.

Programming and control is done via the USB interface. All that is needed is a laptop/desktop computer running a VT100 terminal emulator. Once the program has been written and debugged the PicoMite can be instructed to automatically run the program on power up with no user intervention. Special software is not needed to develop programs.

Pin Marking on Rear

Schematic

• PiPicoMite01 Rev 1 Schematic

Connectors

GP	FUNCTION	PICO PIN
GP6	AUDIO-L	9
GP7	AUDIO-R	10
GND	AUDIO-GND	8
3.3V	PS2_3.3V
VSYS	PS2_5V	39
GP8	PS2_CLK	11
GP9	PS2_DATA	12
GND	PS2_GND	13
3.3V	SD_3.3V
GP12	SD_MISO	16
GP11	SD_MOSI	15
GP10	SD_SCK	14
GP13	SD_SLVSEL	17
GND	SD_GND	18
GP18	VGA_BLU	24
GND	VGA_GND	23
GP20	VGA_GRN_HI	26
GP19	VGA_GRN_LO	25
GP16	VGA_HSYNC	21
GP21	VGA_RED	27
GP17	VGA_VSYNC	22

H1 - 3.3V Power Out

J1 - SD Card

J2 - USB B Power Connectors

• Full size USB B connector
• No USB signal connections, just used for power

J3/J5 Pico Connectors

J4 - I2C Terminators

• Install shunts to terminate SDA, SCL signals

J7 - Audio

J8 - PS/2 Keyboard

J9 - 5V Distribution

J10 - I2C INT

• Install jumper to connect Interrupt from MCP23017 to GP0 pin on Pico
• No Pull-up

P1 - VGA

Prototype Build

• Runs PicoMite (MaxiMite) BASIC (VGA, PS/2)
• Uses cards
  • Raspberry Pico on Breadboard
  • VGAX49
  • PS2X49
  • SD CARD X49
  • GRID49
• Pinouts

Raspberry Pi Pico in a Small Plastic Project Box

• Raspberry Pico on Breadboard

VGAX49

• VGAX49
• Resistors Values
  • Selected for 0.7V output on analog RGB pins
  • R12 = 270
  • R6 = 390
  • R7 = 820
  • R1 = 270

	R,B		G RES		G
Rs	75		R1	390	75
Rm	270		R2	820	264.298
Vin	3.3		RM	264.298	3.3
Vout	0.717				0.729
I (mA)	9.57		I (mA)		9.73

PS2X49

• PS2X49
• PWR1 is the power to the PS/2 #1, #2 connectors (5V)
• +3.3V powers the TXS0104 translator
• Routing
  • CLK1, DAT1 on J3 go to J1 (Purple)
  • CLK2, DAT2 on J3 go to J2 (Not used)

SD CARD X49

• SD CARD X49
• Install NO5V jumper
• Connect 3.3V power
• No 5V attached
• No U2 voltage regulator needed

GRID49 - Audio Filter

• GRID49
• Audio filter circuit

• C1 = Audio_In-L
• D1 - GND
• E1 - Audio_In-R

Cabling

FUNCTION	GP	PICO PIN	CARD	SIG	PIN	COLOUR
AUDIO-GND	GND	8	GRID49	AUD-GND	D1	BLK
AUDIO-L	GP6	9	GRID49	AUD-L	C1	VIO
AUDIO-R	GP7	10	GRID49	AUD-R	E1	YEL
PS2_CLK	GP8	11	PS2X49	CLK1	6	VIO
PS2_DATA	GP9	12	PS2X49	DAT1	8	YEL
PS2_GND	GND	13	PS2X49	GND	10	BLK
SD_SCK	GP10	14	SD_CARD_X49	SCLK	3	VIO
SD_MOSI	GP11	15	SD_CARD_X49	MOSI	4	BLU
SD_MISO	GP12	16	SD_CARD_X49	MISO	2	YEL
SD_SLVSEL	GP13	17	SD_CARD_X49	-SDCS	5	GRY
SD_GND	GND	18	SD_CARD_X49	GND	1	BLK
VGA_HSYNC	GP16	21	VGA	HS	17	GRY
VGA_VSYNC	GP17	22	VGA	VS	18	WHT
VGA_GND	GND	23	VGA	GND	19	BRN
VGA_BLU	GP18	24	VGA	B4	12	BLU
VGA_GRN_LO	GP19	25	VGA	G4	7	GRN
VGA_GRN_HI	GP20	26	VGA	G5	6	GRN
VGA_RED	GP21	27	VGA	R4	1	ORG
PS2_5V	VSYS	39	PS2X49	PWR1	2	ORG
PS2_3.3V	3.3V	BUS	PS2X49	3.3V	4	RED
SD_3.3V	3.3V	BUS	SD_CARD_X49	3.3V	7	RED

Mechanicals

Applications

Tetris

> memory
Program:
  13K (10%) Program (485 lines)
  95K (90%) Free

RAM:
   8K ( 5%) 31 Variables
   0K ( 0%) General
 132K (95%) Free

Assembly Sheet

• PicoMite01 Rev1 Assembly Sheet