KN5000 Hardware Architecture

Detailed hardware documentation extracted from the service manual schematics.

See Also: System Overview for a high-level architecture diagram showing how all subsystems connect.

System Overview

┌────────────────────────────────────────────────────────────────┐
│                         CONTROL PANEL                          │
│  ┌──────────────┐  ┌─────────┐  ┌─────────┐  ┌──────────────┐ │
│  │     CPL      │  │  CPCL   │  │  CPCR   │  │     CPR      │ │
│  │ M37471M2196S │  │ Switches│  │ Switches│  │ M37471M2196S │ │
│  │   8-bit MCU  │  │  LEDs   │  │         │  │   8-bit MCU  │ │
│  └──────┬───────┘  └────┬────┘  └────┬────┘  └──────┬───────┘ │
│         │ SIN/SOUT/CLK  │            │       SIN/SOUT/CLK │   │
└─────────┼───────────────┴────────────┴────────────────────┼───┘
          │                                                 │
          └────────────────────┬────────────────────────────┘
                               │ Serial Bus
┌──────────────────────────────┴─────────────────────────────────┐
│                          MAIN PCB                              │
│                                                                │
│  ┌─────────┐    Latch     ┌─────────┐                         │
│  │  IC5    │◄──0x120000──►│  IC27   │                         │
│  │Main CPU │              │ Sub CPU │                         │
│  │TLCS-900 │              │TLCS-900 │                         │
│  └────┬────┘              └─┬──┬──┬─┘                         │
│       │                     │  │  │                            │
│  ┌────┴────┐           ┌────┘  │  └────┐                      │
│  │ IC206   │           │       │       │                      │
│  │  LCD    │      ┌────┴───┐ ┌─┴────┐ ┌┴───────┐             │
│  │ MN89304 │      │ IC303  │ │IC311 │ │ IC310  │             │
│  └────┬────┘      │Tone Gen│ │ DSP1 │ │  DSP2  │             │
│       │           │TC183C..│ │Effect│ │Mix/EQ  │             │
│  ┌────┴────┐      └────┬───┘ └──────┘ └────────┘             │
│  │ IC207   │           │                                      │
│  │ VRAM    │      ┌────┴───┐                                  │
│  │4Mbit    │      │IC304-6 │   ┌────────┐                    │
│  └─────────┘      │Waveform│   │ IC208  │                    │
│                    │ ROMs   │   │  FDC   │                    │
│                    └────────┘   └────────┘                    │
└───────────────────────────────────────────────────────────────┘

Signal flow: Main CPU handles UI, sequencing, and high-level music control. It sends MIDI-like commands to the Sub CPU via the inter-CPU latch at 0x120000. The Sub CPU translates these into low-level register writes for the tone generator (IC303) and DSP chips (IC310, IC311). Waveform data is stored in IC304-306 (currently undumped). Audio output goes through the DSPs for effects processing and mixing before reaching the DAC.

Control Panel MCUs

Chip Identification

Mitsubishi M37471M2196S (both CPL and CPR boards)

  • 8-bit CMOS microcomputer
  • Mitsubishi 740 series architecture
  • Built-in A/D converter (8 channels)
  • Serial interface (UART)
  • Up to 16 segment outputs for LED multiplexing
  • Mask ROM version (M2196S = specific mask pattern)

CPL Board (Control Panel Left)

Pin/Signal Function
SIN Serial data input (from main CPU)
SOUT Serial data output (to main CPU)
CLK Serial clock
CNTR1 Control/chip select
CMD0-CMD4 Command lines
SW0-SW7 Switch matrix inputs
SEG00-SEG10 LED segment outputs
ROTA, ROTB Rotary encoder inputs
AD0-AD3 A/D converter inputs
BEND Pitch bend wheel (analog)
MOD0, MOD1 Modulation inputs (analog)
MAIN VOLUME Master volume (analog)

CPR Board (Control Panel Right)

Pin/Signal Function
SIN Serial data input
SOUT Serial data output
CLK Serial clock
CNTR1 Control/chip select
CMD0-CMD4 Command lines
SW0-SW7 Switch matrix inputs
SEG00-SEG15 LED segment outputs

LED Driver ICs

HD74LS07P - Hex buffer/driver with open-collector outputs

  • Used for driving LED segments
  • Multiple ICs per board (IC2, IC3)

Main Board ICs

Main CPU

IC5: TMP94C241F

  • Toshiba 32-bit TLCS-900/H2 microcontroller
  • Address bus: A0-A21 (16MB addressable)
  • Data bus: D0-D15 (16-bit)
  • Multiple serial channels
  • DMA controller
  • Timers

Sub CPU (Tone Generator Controller)

IC27: TMP94C241F

  • Toshiba 32-bit TLCS-900/H2 microcontroller (same as main CPU)
  • Up to 20 MHz clock
  • 16 MB linear address space (24-bit addresses)
  • 2 KB internal RAM (0x000800-0x000FFF)

Memory Map:

Address Size Description
0x0000-0x00FF 256B Special Function Registers (SFR)
0x0100-0x01FF 256B Extended SFR (memory controller, DMA, watchdog)
0x0400-0x04E0 225B Interrupt trampolines (copied from ROM)
0x0500-0x05A2 ~160B RAM / Stack area
0x100000 - Audio hardware registers (DSP/DAC interface)
0x110000 - Keyboard/control panel interface
0x120000 - Inter-CPU communication latch
0x130000 - Tone generator registers
0xFE0000-0xFFFFFF 128KB Boot ROM

I/O Capabilities:

  • 2 serial channels (SC0, SC1)
  • 4 8-bit timers (T0-T3)
  • 16-bit timer (T4)
  • DMA controller (channels 0 and 2 used)
  • Multiple GPIO ports (P0-PB, PE, PF)
  • DRAM controller with refresh

Role: Controls tone generator at 0x130000, handles audio synthesis, and communicates with main CPU via latch at 0x120000. Receives 192KB payload from main CPU at boot.

Memory

IC Part Number Type Size Function
IC1 QS6C5008E13 ROM 8Mbit Table Data (ODD)
IC3 QS6C5D0ME11 ROM 8Mbit Table Data (EVEN)
IC4 QV1GFKN5KAX1 ROM 8Mbit Program (EVEN)
IC6 QV1GFKN5KAX1 ROM 8Mbit Program (ODD)
IC9 M5M44260AJ7S DRAM 4Mbit Dynamic RAM
IC10 M5M44260AJ7S DRAM 4Mbit Dynamic RAM
IC14 QS6C303C301I ROM - Additional ROM
IC19 QV1GFKN5KAX1 ROM 8Mbit Custom Data
IC21 - SRAM 1Mbit Backup (battery)

ROM Interleaving Formats

The KN5000 uses different data organization depending on the ROM:

ROM Chips Interleaving Size Address Range
Program ROM IC4 (even) + IC6 (odd) 16-bit word-level 2MB 0xE00000-0xFFFFFF
Table Data ROM IC3 (even) + IC1 (odd) 16-bit word-level 2MB 0x800000-0x9FFFFF
Sub CPU Boot ROM IC30 (internal) None (single chip) 128KB 0xFE0000-0xFFFFFF
Custom Data Flash IC19 None (single chip) 1MB 0x300000-0x3FFFFF
HDAE5000 ROM IC4 (expansion) None (single chip) 512KB 0x280000-0x2FFFFF
Sub CPU Payload Transferred via latch None (in-memory) 192KB 0x002000-0x031FFF

16-bit word-level interleaving means the two physical ROM chips store alternating 16-bit words:

Combined ROM:   [WORD0_LO][WORD0_HI] [WORD1_LO][WORD1_HI] [WORD2_LO][WORD2_HI] ...
Even chip (IC3): WORD0_LO  WORD0_HI   WORD1_LO  WORD1_HI   ...  (bytes 0,1 of each word)
Odd chip (IC1):                                                    (bytes 0,1 of each word)

To reconstruct the combined ROM from the two chip dumps:

combined[2*i]     = even[i]    (low byte of word i)
combined[2*i + 1] = odd[i]     (high byte of word i)

This is not the same as byte-level interleaving (even[0], odd[0], even[1], odd[1]) — each chip stores complete 16-bit values, and the CPU’s 16-bit data bus reads one word at a time from the appropriate chip.

Audio / Sound Generation

IC Part Number Function Interface
IC303 TC183C230002 Tone Generator Memory-mapped at 0x100000 (SubCPU)
IC310 MN19413 DSP2 (mixing/EQ) Serial GPIO bit-bang (SubCPU)
IC311 DS3613GF-3BA DSP1 (effects) Memory-mapped at 0x130000 + parallel port (P7/PZ)
IC304-306 — Waveform ROMs Connected to IC303 (undumped)

The tone generator IC303 handles polyphonic synthesis with 64 voice channels, while IC311 (DSP1) provides digital effects (reverb, chorus, delay, distortion) and IC310 (DSP2) handles mixing and EQ. The SubCPU controls all three via dedicated interfaces.

See Audio Subsystem for detailed protocol documentation.

Peripherals

IC Part Number Function
IC24 MN1382QTX Reset Controller
IC206 MN89304 LCD Controller
IC207 M5M44265CJ8S 4Mbit Video RAM
IC208 D72068GF-3B9 Floppy Disk Controller

HDAE5000 Hard Disk Expansion (Optional)

The HD-AE5000 is an optional expansion providing 1.08GB storage.

Component Address Description
PPI (8255) 0x160000-0x160006 Programmable Peripheral Interface
ROM 0x280000 512KB firmware ROM

PPI Port Mapping:

Address Port Function
0x160000 Port A Data output to HD controller
0x160002 Port B Status input from HD controller
0x160004 Port C Control signals (strobe, handshake)
0x160006 Control PPI mode configuration (0x82)

Detection: PE port bit 0 (active low) indicates HDAE5000 presence.

See HDAE5000 page for firmware details.

LCD Controller (MN89304)

The MN89304 provides a VGA-compatible register interface at I/O base 0x170000.

Memory Map:

Address Description
0x170000 + port VGA I/O registers
0x1A0000 Video RAM base (512KB)

VGA I/O Ports:

Port Register Description
0x3C0 Attribute Controller Address/Data
0x3C2 Misc Output Write only
0x3C4/3C5 Sequencer Address/Data
0x3C6 DAC Mask Palette mask
0x3C8/3C9 DAC Write address/Data
0x3CE/3CF Graphics Controller Address/Data
0x3D4/3D5 CRTC Address/Data
0x3DA Input Status 1 Read only

CRTC Register Indices:

Index Name Description
0x00 CRTC_HORIZ_TOTAL Horizontal Total
0x01 CRTC_HORIZ_DISP_END Horizontal Display End
0x06 CRTC_VERT_TOTAL Vertical Total
0x07 CRTC_OVERFLOW Overflow bits
0x09 CRTC_MAX_SCAN_LINE Maximum Scan Line
0x0C/0D CRTC_START_ADDR Display start address
0x10 CRTC_VERT_RETRACE_START Vertical Retrace Start
0x11 CRTC_VERT_RETRACE_END Vertical Retrace End (bit 7 = protect)
0x12 CRTC_VERT_DISP_END Vertical Display End
0x17 CRTC_MODE_CONTROL Mode Control

Registers 0x19 and 0x1A are MN89304-specific extensions (not standard VGA).

Logic ICs

IC Part Number Function
IC11 TC74VHC139F 2-to-4 Decoder
IC12 T7W139F 2-to-4 Decoder
IC13 TC74VHC139F 3-to-8 Decoder
IC16B D74HC164GS Shift Register
IC17, IC31 TC7W32FU Dual 2-input OR gates

Button Mapping

CPL Board (Left Side Panel)

RHYTHM GROUP:

  • D1: Standard Rock
  • D2: R & R Blues
  • D3: Pop & Ballad
  • D4: Funk & Fusion
  • D5: Modern Dance
  • D6: Swing
  • D7: Jazz Combo

COMPOSER:

  • D101: Memory
  • D102: Menu
  • D103: Set
  • D104: On/Off
  • D105: Music Stylist

VARIATION & MEM:

  • D17: Demo
  • D25-D28: Bank, Menu, Stoprecord, etc.

FILL IN / INTRO & ENDING:

  • D125-D134: Various fill and ending controls

CPR Board (Right Side Panel)

SOUND GROUP:

  • D8: Accordion
  • D9: Digital
  • D10: Guitar
  • D14: Flute
  • D15: Sax & Reed
  • D21: Piano
  • D22: Strings & Vocal

PART SELECT:

  • D33: Sustain
  • D34: Left
  • D35: Right 1
  • D36: Right 2

PANEL MEMORY:

  • D49-D56: Memory 1-8
  • D57: Next Bank
  • D58: Bank View

SEQUENCER:

  • D160+: Easy Rec, Menu, Sound, Control, Mix, Disk

Serial Protocol Hardware

The control panel MCUs communicate with the main CPU via a serial interface:

Main CPU (TMP94C241F)          Control Panel MCU (M37471M2196S)
        │                               │
        │<──────── SOUT ────────────────│ (Data from panel)
        │                               │
        │─────────> SIN ───────────────>│ (Data to panel)
        │                               │
        │─────────> CLK ───────────────>│ (Clock)
        │                               │
        │─────────> CNTR1 ─────────────>│ (Control)
        │                               │
        │─────────> CMD0-4 ────────────>│ (Commands?)

The exact protocol details must be reverse-engineered from the main CPU firmware disassembly.

References

  • Service Manual: EMID971655 A5 (Download PDF - 26MB)
  • Schematic pages: II-9 through II-38