[intellivision] add current pico code. (#990)

* [intellivision] add current pico code.

* remove list file.

* Add the intv bring-up lab.

Author: tschak909

pico/intellivision/.gitignore

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+build
+!.vscode/*

pico/intellivision/CMakeLists.txt

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+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Initialise pico_sdk from installed location
+# (note this can come from environment, CMake cache etc)
+
+# == DO NOT EDIT THE FOLLOWING LINES for the Raspberry Pi Pico VS Code Extension to work ==
+if(WIN32)
+    set(USERHOME $ENV{USERPROFILE})
+else()
+    set(USERHOME $ENV{HOME})
+endif()
+set(sdkVersion 2.1.1)
+set(toolchainVersion 14_2_Rel1)
+set(picotoolVersion 2.1.1)
+set(picoVscode ${USERHOME}/.pico-sdk/cmake/pico-vscode.cmake)
+if (EXISTS ${picoVscode})
+    include(${picoVscode})
+endif()
+# ====================================================================================
+set(PICO_BOARD pico CACHE STRING "Board type")
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include(pico_sdk_import.cmake)
+
+project(fuji-intv C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(fuji-intv fuji-intv.c )
+
+pico_set_program_name(fuji-intv "fuji-intv")
+pico_set_program_version(fuji-intv "0.1")
+
+# no_flash means the target is to run from RAM
+pico_set_binary_type(fuji-intv no_flash)
+
+# Generate PIO header
+pico_generate_pio_header(fuji-intv ${CMAKE_CURRENT_LIST_DIR}/bus_decode.pio)
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(fuji-intv 0)
+pico_enable_stdio_usb(fuji-intv 1)
+
+# Add the standard library to the build
+target_link_libraries(fuji-intv
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(fuji-intv PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+# Add any user requested libraries
+target_link_libraries(fuji-intv
+        hardware_pio
+        )
+
+pico_add_extra_outputs(fuji-intv)
+

pico/intellivision/README.md

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+# fuji-intv-bring-up-lab
+
+This repo contains RP2040 code used for the bring-up of the Intellivision FujiNet using a PiRTO II cart.
+
+There are two goals:
+
+(1) Emulate a ROM properly on the CP-1610 bus.
+(2) Communicate a command frame to FujiNet, and back.
+
+This firmware will be supplanted by the real thing, soon enough. But for now, it's here so others can jump in and help.
+
+-Thom

pico/intellivision/bus_decode.pio

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+// Receives 19 bits: DB0–DB15 + BDIR + BC2 + BC1
+.program cp1600_bus_rx
+.define PINS_TO_SAMPLE 19 ; # of pins to sample.
+.wrap_target
+    wait 1 pin 16        ; Wait for BDIR == 1 (CPU driving bus)
+    nop [31]             ; 279.3ns valid delay
+    nop [31]             ; at 250MHz.
+    nop [5]
+    in pins, PINS_TO_SAMPLE          ; Read pins
+    in null, 13
+    push block
+    wait 0 pin 16        ; Wait for BDIR == 0 (CPU released bus)
+.wrap
+
+// Transmits 16 bits onto DB0–15 during DTB
+.program cp1600_bus_tx
+.wrap_target
+    wait 0 pin 16        ; BDIR == 0
+    wait 1 pin 17        ; BC2 == 1
+    wait 1 pin 18        ; BC1 == 1 => DTB
+    out pins, 16         ; Output data onto DB0–15
+.wrap