Jump to content
IGNORED

Some Errata


Recommended Posts

Rather than edit my original messages, and hope nobody notices... I've decided to point out my original errors in this errata, so that people are aware what I originally said - and what I should have said.

 

In Session 1 (the first post), I talked about EEPROM. These are electrically-erasable Read-Only Memory, and I never used them. I should have said EPROM - which are erased with ultra-violet light.

 

In Session 2 I mention SECAM being used in France and Russia. SECAM is also used in the middle east and other ex-French colonies (Viet Nam) SECAM is very similar to PAL (625/50Hz).

 

Also in session 2, I wrote

 

"The Atari 2600 *ONLY* sends the TV the "colour and intensity information for the electron beam as it sweeps across that line". The '2600 programmer needs to feed the TV the rest of the information - basically, the signal to start the image frame, and the signal to tell it to start the next scanline, and the next.... etc."

 

This is not correct. Every scanline, the TIA automatically inserts the correct signal for the start of the scanline (it's called the HSYNC signal). The vertical synchronisation signal (VSYNCH) which tells the TV when to start a new frame is the responsibility of the programmer.

 

In Session 3, I wrote...

 

"A side-note: 76 cycles per line x 262 lines per frame x 50 frames per second = the number of 6502 cycles per second for NTSC (= 1.19MHz, roughly)."

 

Astute readers will have noticed that NTSC is 60 frames per second, not 50.

 

Thanks to Eric Ball for his suggestions and corrections.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...