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How is the Apple II text flash mode timed?

It's a fixed timing signal generated by an NE555 timer (at position B3 on the original II+).

 (From the Apple II Reference Manual / Red Book p.151)

Entering the values of C/R1/R2 into an online calculator for NE555s will give about 2.1 seconds cycle time (*1)

The II's video logic used bit 2^6 and 2^7 to control the level in text mode.

7  6
0  0  - Inverted
0  1  - Inverted depending on the timer
1  0  - Not inverted

This is as well visible in the (screen) character set:

This as well shows that the Apple II character generator only holds 64 different glyphs - using above logic to produce them in Normal/Inverted/Flash.

There is no hardware cursor. It's essentially done by setting the two top bits of the character were the cursor should be shown to 01 (*2).

For the second part:

an extension would be why is the cursor is affected but not the text display?

I'm not entirely clear what you describe/ask.

*1 - These are analogue parts with up to 10% or more variation.

*2 - this is also, why pressing Reset may result having the 'old' cursor still blinking while a new one is displayed.

How is the Apple II text flash mode timed?

It's a fixed timing signal generated by an NE555 timer (at position B3 on the original II+).

(From the Apple II Reference Manual / Red Book p.151)

Entering the values of C/R1/R2 into an online calculator for NE555s will give about 2.1 Hz cycle time (*1)

The II's video logic used bit 2^6 and 2^7 to control the level in text mode.

7  6
0  0  - Inverted
0  1  - Inverted depending on the timer
1  0  - Not inverted

This is as well visible in the (screen) character set:

This as well shows that the Apple II character generator only holds 64 different glyphs - using above logic to produce them in Normal/Inverted/Flash.

There is no hardware cursor. It's essentially done by setting the two top bits of the character were the cursor should be shown to 01 (*2).

For the second part:

an extension would be why is the cursor is affected but not the text display?

I'm not entirely clear what you describe/ask.

*1 - These are analogue parts with 10% or more variation, so observed speed may vary.

*2 - this is also, why pressing Reset may result having the 'old' cursor still blinking while a new one is displayed.

How is the Apple II text flash mode timed?

It's a fixed timing signal generated by an NE555 timer (at position B3 on th original II+).

(From the Apple II Reference Manual / Red Book p.151)

The II's video logic used bit 2^6 and 2^7 to control the level in text mode.

7  6
0  0  - Inverted
0  1  - Inverted depending on the timer
1  0  - Not inverted

This is as well visible in the (screen) character set:

This as well shows that the Apple II character generator only holds 64 different glyphs - using above logic to produce them in Normal/Inverted/Flash.

For the second part:

an extension would be why is the cursor is affected but not the text display?

I'm not entirely clear what you describe/ask.

How is the Apple II text flash mode timed?

It's a fixed timing signal generated by an NE555 timer (at position B3 on the original II+).

(From the Apple II Reference Manual / Red Book p.151)

Entering the values of C/R1/R2 into an online calculator for NE555s will give about 2.1 seconds cycle time (*1)

The II's video logic used bit 2^6 and 2^7 to control the level in text mode.

7  6
0  0  - Inverted
0  1  - Inverted depending on the timer
1  0  - Not inverted

This is as well visible in the (screen) character set:

This as well shows that the Apple II character generator only holds 64 different glyphs - using above logic to produce them in Normal/Inverted/Flash.

There is no hardware cursor. It's essentially done by setting the two top bits of the character were the cursor should be shown to 01 (*2).

For the second part:

an extension would be why is the cursor is affected but not the text display?

I'm not entirely clear what you describe/ask.

*1 - These are analogue parts with up to 10% or more variation.

*2 - this is also, why pressing Reset may result having the 'old' cursor still blinking while a new one is displayed.

How is the Apple II text flash mode timed?

It's a fixed timing signal generated by an NE555 timer (at position B3 on th original II+).

The II's video logic used bit 2^6 and 2^7 to control the level in text mode.

7  6
0  0  - Inverted
0  1  - Inverted depending on the timer
1  0  - Not inverted

(From the Apple II Reference Manual / Red Book p.151)

For the second part:

an extension would be why is the cursor is affected but not the text display?

I'm not entirely clear what you mean.

How is the Apple II text flash mode timed?

It's a fixed timing signal generated by an NE555 timer (at position B3 on th original II+).

(From the Apple II Reference Manual / Red Book p.151)

The II's video logic used bit 2^6 and 2^7 to control the level in text mode.

7  6
0  0  - Inverted
0  1  - Inverted depending on the timer
1  0  - Not inverted

This is as well visible in the (screen) character set:

This as well shows that the Apple II character generator only holds 64 different glyphs - using above logic to produce them in Normal/Inverted/Flash.

For the second part:

an extension would be why is the cursor is affected but not the text display?

I'm not entirely clear what you describe/ask.