Difference between revisions of "PiPicoMite03"

Revision as of 10:40, 18 June 2022

Features

Targeted to fit in extruded Aluminum box
Raspberry Pi Pico
- Pico pin marking on rear
VGA
- 640x480 monochrome resolution
- 320x240 colour resolution
- 1:2:1 - R:G:B - 16 colours
PS/2 Keyboard
- 5V to keyboard with voltage translator
- Does not require a keyboard that runs at 3.3V
SD Card
- Full size card
- Up to 32GB
- FAT32 format
Stereo audio
- PWM with filter
- 3.5mm jack
I2C0 connector (DS1307 RTC compatible)
5V power input on USB B
99.5mmx69.5mm outline

BASIC Interpreter

The PicoMiteVGA boots straight into the MMBasic prompt. At which point you can enter, edit and save the program, test BASIC commands and run the program.

MMBasic is a Microsoft BASIC compatible implementation of the BASIC language, originally written by Geoff Graham and enhanced and ported to the Pico by Peter Mather, who also designed the original PicoMite on which thiis design is based. It is full featured with 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. Embedded compiled C programs can be used for even higher performance.

Using MMBasic you can use communications protocols such as I2C or SPI to get data from a variety of sensors. You can save data to an SD card, measure voltages, detect digital inputs and drive output pins to turn on lights, relays, etc.

The emphasis with MMBasic is on ease of use and development. The development cycle is very fast with the ability to instantly switch from edit to run. Errors are listed in plain English and when an error does occur a single keystroke will invoke the built in editor with the cursor positioned on the line that caused the error.

Pinout

Pin Marking on Rear

Schematic

PiPicoMite03 Rev 1 Schematic

Connectors

J1 - VGA

The VGA output is 640 x 480 pixels in monochrome mode or 320 x 240 pixels in colour mode with 16 colours (1 bit for red, 2 bits for green and 1 bit for blue). The VGA output is generated using the second CPU on the RP2040 processor plus one PIO channel so it does not affect the BASIC interpreter which runs at full speed on the first CPU. A handfull of components (resistors and a couple of diodes) is all that is required to connect the VGA monitor.

From within your BASIC program you can turn pixels on/off and draw lines, boxes and circles in any colour. Text can be positioned anywhere on the screen and displayed in any colour in a variety of fonts.

The built-in editor within MMBasic works perfectly with the VGA monitor and PS2 keyboard to allow programs to be edited (with colour coded text) and saved to an SD card.

Mode 1 (640x480 monochrome) and mode 2 (320x240 16-colours).

OPTION COLOURCODE ON

Audio

Low Pass filter
Resistive voltage divider to get to line level
- Line Level Audio information
Two Tone Test
Play a WAV file

OPTION AUDIO GP6, GP7
PLAY WAV "file.wav"
PLAY STOP

USB B Power Connector

In parallel with J6

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

PS/2 Keyboard

The PS2 keyboard connects to the Raspberry Pi Pico via a level shifter and works as a normal keyboard with the function keys and arrow keys fully operational. It can be configured for the standard US layout used in the USA, Australia and New Zealand or specialised layouts used in the United Kingdom, Germany, France and Spain.

5V keyboard

I2C0, UART0 (RTC, etc.)

I2C0SCL. UART0_TX (GP1)
I2C0SDA. UART0_RX (GP0)
VCC
GND

Can use Real Time Clocks using the PCF8563, DS1307, DS3231 or DS3232 chips means that the time is always accurately known.

option system i2c gp0, gp1

Pico GVS Connectors

Spare Pico pins are brought out to 1x20 pin headers J9, J10

SD Card

The PicoMiteVGA firmware reserves eight program storage "slots" in the Raspberry Pi Pico flash memory. Programs can be saved and retreived from these without the need for any additional storage.

For more storage SD cards can be connected with full support for these built into MMBasic including the ability to open files for reading, writing or random access and loading and saving programs. SD cards connect directly to the Raspberry Pi Pico and the firmware will work with cards up to 32GB formatted in FAT16 or FAT32. The files created can be read and written on personal computers running Windows, Linux or the Mac operating system.

OPTION SDCARD GP13, GP10, GP11, GP12

Configuration Options

> OPTION LIST
OPTION COLOURCODE ON
OPTION KEYBOARD US
OPTION SDCARD GP13, GP10, GP11, GP12
OPTION AUDIO GP6,GP7, ON PWM CHANNEL 3
option system i2c gp0, gp1

Mechanicals

PicoMite Software

PicoMite Source code

PicoMite Source code
- Extra/replacement files for VGA

Factory Test

Equipment

Unit Under Test (UUT)
VGA monitor
Stereo amplified speakers
PS/2 keyboard
MBASIC SD card
Raspberry Pi Pico
PC running TeraTerm

Download MMBASIC

If the Pico does not already have MMBASIC installed
Hold button in Pico
Plug in USB Micro to PC
Drive will open
Drop VGA uf2 onto Drive
System will reboot
Run TeraTerm
- Serial

Configure MMBASIC

Setups
- Can copy-paste a line at a time into TeraTerm
- First two will reboot card

OPTION SDCARD GP13, GP10, GP11, GP12
OPTION AUDIO GP6,GP7, ON PWM CHANNEL 3
OPTION COLOURCODE ON

Remove USB power
Install SD card
Apply USB power

Test SD card interface

Type

files

Returns

A:/
   <DIR>  basic
   <DIR>  bmps
   <DIR>  demos
   <DIR>  games
   <DIR>  jpegs
   <DIR>  lbcards
   <DIR>  performance
   <DIR>  wave
8 directories, 0 files

Test Sound

Type

chdir "/wave"
play wav "sample4.wav"

Sound should come out of speakers
Stop with

play stop

Test GPIO (Rev 2 card) (optional MCP23017 is installed)

Connect LED-32 card to J1
Type

chdir "/lbcards/GPIO16"
> load "MCP23017_BLINKEY.BAS"
> run
Blink a bit on the On-board MCP23017 PORTA Bit 0
Hit a key to stop

Single LED will blink
Any key will stop the program

flash save 1

Type

>load "gpio16-01.bas"
>run
Looping through LEDs
Hit a key to stop

LEDs will blink
Any key will stop the program

flash save 2

Test 5V in

Connect USB B to 5V (or PC)
Remove USB Micro cable
Card should continue to run

Test I2C

Use DS1307 RTC attached to I2C J1

option system i2c gp0, gp1
rtc gettime
print time$

Issues

Rev 1

Not yet ordered

Assembly Sheet

Make sure you build with the current revision assembly sheet
- Revision is marked on the rear of the card
PiPicoMite03 Rev1 Assembly Sheet

Revision as of 09:25, 18 June 2022 (view source) Blwikiadmin (talk \| contribs) (→‎MMBASIC vs MicroPython Performance) ← Older edit		Revision as of 10:40, 18 June 2022 (view source) Blwikiadmin (talk \| contribs) (→‎VGA) Newer edit →
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−	=== VGA ===	+	=== J1 - VGA ===

	The VGA output is 640 x 480 pixels in monochrome mode or 320 x 240 pixels in colour mode with 16 colours (1 bit for red, 2 bits for green and 1 bit for blue). The VGA output is generated using the second CPU on the RP2040 processor plus one PIO channel so it does not affect the BASIC interpreter which runs at full speed on the first CPU. A handfull of components (resistors and a couple of diodes) is all that is required to connect the VGA monitor.		The VGA output is 640 x 480 pixels in monochrome mode or 320 x 240 pixels in colour mode with 16 colours (1 bit for red, 2 bits for green and 1 bit for blue). The VGA output is generated using the second CPU on the RP2040 processor plus one PIO channel so it does not affect the BASIC interpreter which runs at full speed on the first CPU. A handfull of components (resistors and a couple of diodes) is all that is required to connect the VGA monitor.