Lynx cartridge port pins 33 VCC / 34 SWVCC

[+doctorclu]

Once again reading the Best Electronics Catalog, I see Lynx cartridge port pins 33 VCC / 34 SWVCC.

 

What exactly are those used for?

 

Attaching a quick picture of the Lynx cartridge port pinouts if anyone else is passingly curious on this like I am at the moment.

[TailChao]

VCC is +5VDC.

SWVCC is software controlled VCC (Also +5VDC). The power to this pin can be disabled in software, and thus is handy for "shutting off" the cartridge ROM or anything else that may be connected to it. This can conserve energy if the software does not need to constantly load from the cartridge, or if the ROM does not have a low power mode.

[+karri]

VCC is +5VDC.

SWVCC is software controlled VCC (Also +5VDC). The power to this pin can be disabled in software, and thus is handy for "shutting off" the cartridge ROM or anything else that may be connected to it. This can conserve energy if the software does not need to constantly load from the cartridge, or if the ROM does not have a low power mode.

 

The names are very badly chosen in the docs.

 

Pin 10 is usually called CART0/

It is really the read strobe while pin 34 SWVCC is the chip enable. You cannot really control it. Every read cycle to the cart will set pin 34 high.

 

Pin 27 CART1/ is used as a write strobe to the cart. Currently writes are used for a few special devices. I am aware of:

- EEPROM for saving high score

- devflash for programming a game on a cart

- EOTB saves to a 16k RAM

 

In theory you could also use CART1/ for adding a second memory chip on the cart. But usually the 2nd chip is added by using pin 32 instead. Examples of 2 chip designs are:

- 42Bastian driving school

- Alpine Games

 

I am not aware of any cart that would use CART1/ strobes for reading.

 

--

Karri

[TailChao]

The names are very badly chosen in the docs.

Unbelievably so. Which is strange since Epyx's development kit is very good, and you would think that the documentation would be similarly well made.

Edited July 23, 2009 by TailChao

[sage]

- EOTB saves to a 16k RAM

 

I am not aware of any cart that would use CART1/ strobes for reading.

 

 

actually, EOTB uses CART1 strobe for reading and writing. AUDIN is used fro switching read/write to SRAM/EPROM