Timing: Difference between revisions

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== Clocks ==
== Clocks ==


The WonderSwan is clocked with a master clock of approximately 12288000 Hz (= 12.288 MHz).
The WonderSwan is clocked with a ''master clock'' of approximately 12288000 Hz (= 12.288 MHz).


This clock is split into four internal memory access quadrants, running at 3072000 Hz (= 3.072 MHz) each. Three of those are used by the console in "mono" mode: [[CPU|NEC V30MZ]], [[Display]] and [[Sound]]. On the WonderSwan Color, the fourth quadrant is used to handle color palette reads during display drawing.
This clock is split into four internal memory access quadrants, running at 3072000 Hz (= 3.072 MHz) each. Three of those are used by the console in "mono" mode:


Out of those, only the CPU quadrant can access the cartridge bus. It can be additionally configured to use one of two wait states:
* [[CPU|NEC V30MZ]] - referred to as the ''CPU clock'',
* [[Display]],
* [[Sound]].


* 1 cycle access - an effective bus speed of 3072000 Hz, same as the CPU,
On the WonderSwan Color, the fourth quadrant is used to handle color palette reads during display drawing.
* 3 cycle access - an effective bus speed of 1024000 Hz.


== Display ==
Only the CPU quadrant can access the cartridge bus; this means that [[DMA]] necessarily stalls the CPU.
 
In addition, a separate 384000 Hz (3072000 / 8) ''cartridge clock'' is provided on one of the cartridge pins.
 
== Display timing ==


By default, a WonderSwan frame consists of 159 lines, 144 of which are visible. Each line consists of 256 clock cycles, of which 224 are used to draw a pixel at a time. This leads to a total duration of 40704 clock cycles per frame, for an effective default refresh rate of approximately 75.472 Hz.
By default, a WonderSwan frame consists of 159 lines, 144 of which are visible. Each line consists of 256 clock cycles, of which 224 are used to draw a pixel at a time. This leads to a total duration of 40704 clock cycles per frame, for an effective default refresh rate of approximately 75.472 Hz.


Vertical blanks are always triggered on line 144; if the display is set to be shorter than 144 lines, vertical blank interrupts will never be triggered.
Vertical blanks are always triggered on line 144; if the display is set to be shorter than 144 lines, vertical blank interrupts will never be triggered.
TODO: back/front porches, etc.
== Frame timing ==
The details of per-line and per-frame timing are available in a table on the [[Frame timing]] page.

Latest revision as of 18:20, 22 August 2023

Clocks

The WonderSwan is clocked with a master clock of approximately 12288000 Hz (= 12.288 MHz).

This clock is split into four internal memory access quadrants, running at 3072000 Hz (= 3.072 MHz) each. Three of those are used by the console in "mono" mode:

On the WonderSwan Color, the fourth quadrant is used to handle color palette reads during display drawing.

Only the CPU quadrant can access the cartridge bus; this means that DMA necessarily stalls the CPU.

In addition, a separate 384000 Hz (3072000 / 8) cartridge clock is provided on one of the cartridge pins.

Display timing

By default, a WonderSwan frame consists of 159 lines, 144 of which are visible. Each line consists of 256 clock cycles, of which 224 are used to draw a pixel at a time. This leads to a total duration of 40704 clock cycles per frame, for an effective default refresh rate of approximately 75.472 Hz.

Vertical blanks are always triggered on line 144; if the display is set to be shorter than 144 lines, vertical blank interrupts will never be triggered.

TODO: back/front porches, etc.

Frame timing

The details of per-line and per-frame timing are available in a table on the Frame timing page.