Difference between revisions of "Debug device"

From MSX Game Library

(Debug device protocol)
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== Debug device protocol ==
 
== Debug device protocol ==
The additions are in <b>bold</b>.
+
The additions are in <b>bold</b>. This proposal is 100% compatible with the old one if unused bits was set to 0.
  
 
  -----------------------------------------------------------------------------
 
  -----------------------------------------------------------------------------

Revision as of 18:51, 27 July 2023

Proposal to improve the debugging protocol used by openMSX pseudo-device.

Based on: https://openmsx.org/manual/user.html#debugdevice

Debug device protocol

The additions are in bold. This proposal is 100% compatible with the old one if unused bits was set to 0.

-----------------------------------------------------------------------------
 Port 0x2E - Mode Set Register
-----------------------------------------------------------------------------
 7   6   5   4   3   2   1   0
 │   │   │   │   └───┴───┴───┴── Mode-specific parameters
 │   │   └───┴────────────────── Output mode (0 = OFF, 1 = single byte, 2 = multi byte)
 │   └────────────────────────── Line feed mode (0 = line feed at mode change, 1 = no line feed)
 └────────────────────────────── Functionality (0 = output, 1 = command)

-----------------------------------------------------------------------------
 Functionality = output, Output mode = single byte
-----------------------------------------------------------------------------
 7   6   5   4   3   2   1   0
 ‖   ‖   ‖   ‖   │   │   │   └── Hexadecimal mode (0 = OFF, 1 = ON)
 0   ?   0   1   │   │   └────── Binary mode (0 = OFF, 1 = ON)
                 │   └────────── Decimal mode (0 = OFF, 1 = ON)
                 └────────────── ASCII mode (0 = OFF, 1 = ON)

-----------------------------------------------------------------------------
 Functionality = output, Output mode = multi byte
-----------------------------------------------------------------------------
 7   6   5   4   3   2   1   0
 ‖   ‖   ‖   ‖   │   │   └───┴── Mode (0 = hex, 1 = binary, 2 = decimal, 3 = ASCII mode)
 0   ?   1   1   │   └────────── Data width (0 = 8 bits; 1 = 16 bits)
                 └────────────── Signed (0 = unsigned, 1 = signed)

-----------------------------------------------------------------------------
 Functionality = command
-----------------------------------------------------------------------------
 7   6   5   4   3   2   1   0
 ‖   └───┴───┴───┴───┴───┴───┴── Command ID (0x7F = break point)
 1