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Update README for 1.1.0

This commit is contained in:
Seth Morabito 2015-12-31 16:38:27 -08:00
parent da2750f4ee
commit 7daeb9e978
4 changed files with 35 additions and 20 deletions

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@ -103,19 +103,32 @@ Memory contents can be viewed (and edited) one page at a time through the Memory
![Trace Log] (https://github.com/sethm/symon/raw/master/screenshots/trace_log.png)
The last 20,000 execution steps are disassembled and logged to the Trace Log Window.
The last 20,000 execution steps are disassembled and logged to the Trace Log
Window.
### 3.6 NEW - Experimental 6545 CRTC Video
### 3.6 Simulator Speeds
![Speeds] (https://github.com/sethm/symon/raw/master/screenshots/simulator_menu.png)
Simulated speeds may be set from 1MHz to 8MHz.
### 3.7 Breakpoints
![Breakpoints] (https://github.com/sethm/symon/raw/master/screenshots/breakpoints.png)
Breakpoints can be set and removed through the Breakpoints window.
### 3.8 Experimental 6545 CRTC Video
![Composite Video] (https://github.com/sethm/symon/raw/master/screenshots/video_window.png)
This feature is highly experimental. It's possible to open a video window from the "View" menu.
This window simulates the output of a MOS 6545 CRT Controller located at address `$9000` and
`$9001`.
This feature is highly experimental. It's possible to open a video window
from the "View" menu. This window simulates the output of a MOS 6545 CRT
Controller located at address `$9000` and `$9001`.
By default, the 40 x 25 character display uses video memory located at base address `$7000`.
This means that the memory from address `$7000` (28672 decimal) to `$73E8` (29672 decimal)
is directly mapped to video.
By default, the 40 x 25 character display uses video memory located at base
address `$7000`. This means that the memory from address `$7000` (28672
decimal) to `$73E8` (29672 decimal) is directly mapped to video.
- Address Register (at address `$9000`)
- R1: Horizontal Displayed Columns
@ -128,18 +141,20 @@ is directly mapped to video.
- R14: Cursor Position (High Byte)
- R15: Cursor Position (Low Byte)
Although the simulation is pretty good, there are a few key differences between
the simulated 6545 and a real 6545:
Although the simulation is pretty good, there are a few key differences
between the simulated 6545 and a real 6545:
- The simulated 6545 supports only the straight binary addressing mode of the real 6545,
and not the Row/Column addressing mode.
- The simulated 6545 has full 16 bit addressing, where the real 6545 has only
a 14-bit address bus.
- The simulation is done at a whole-frame level, meaning that lots of
6545 programming tricks that were achieved by updating the frame address
during vertical and horizontal sync times are not achievable. There is no way
(for example) to change the Display Start Address (R12 and R13) while a
frame is being drawn.
- The simulated 6545 supports only the straight binary addressing
mode of the real 6545, and not the Row/Column addressing mode.
- The simulated 6545 has full 16 bit addressing, where the real 6545
has only a 14-bit address bus.
- The simulation is done at a whole-frame level, meaning that lots
of 6545 programming tricks that were achieved by updating the
frame address during vertical and horizontal sync times are not
achievable. There is no way (for example) to change the Display Start
Address (R12 and R13) while a frame is being drawn.
For more information on the 6545 CRTC and its programming model, please see the following resources
@ -148,7 +163,7 @@ For more information on the 6545 CRTC and its programming model, please see the
- [MOS 6545 Datasheet (PDF)] (http://www.6502.org/users/andre/hwinfo/crtc/crtc.html)
#### 3.6.1 Example BASIC Program to test Video
#### 3.8.1 Example BASIC Program to test Video
This program will fill the video screen with all printable characters.

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