Using Your Jaguar Without A Game

[Zerosquare]

[English]

I think GT was the one who asked me this question at the Retro-Gaming Connexion : how can you use your Jaguar for BJL without having a game inserted ? For those interested, the answer is simple : all you have to do is shunt two adjacent pins on the cartridge port (34B and 35B, i.e. respectively CART_IN and CART_OUT on the schematic). Here's a little picture I made to make it clearer.

[Français]

Je crois que c'est GT qui m'a posé la question à la Retro-Gaming Connexion : comment utiliser sa Jaguar pour le BJL sans devoir avoir un jeu d'inséré ? Pour ceux que ça intéresse, la réponse est simple : il suffit de court-circuiter deux broches adjacentes sur le port cartouche (34B et 35B, soit respectivement CART_IN et CART_OUT sur le schéma). Voilà une petite photo que j'ai faite pour que ce soit plus clair.

 

[GT Turbo]

Thanks Zero, let's solder !!

 

 

GT

 

Edit : Done

[SebRmv]

ah, super!

va falloir resortir le bleu de chauffe

[LinkoVitch]

One thing that I wondered about doing this myself is if leaving the memory bus open and unterminated would possibly cause issues at high speed due to reflections on the bus from the unterminated end of the bus.

 

has Anyone who has done this seen odd behaviour ?

[Zerosquare]

One thing that I wondered about doing this myself is if leaving the memory bus open and unterminated would possibly cause issues at high speed due to reflections on the bus from the unterminated end of the bus.

 

has Anyone who has done this seen odd behaviour ?

That's an interesting question. I've been running my Jaguar like that since January, and nothing out of the ordinary happened.

 

Anyways, cartridges don't have internal termination either ; apart from a few picofarads of stray capacitance and a few microamps of leakage current, inputs on the ROMs basically act as an open circuit. And the Jag has internal pull-ups resistors on the bus, so it isn't floating even if nothing is driving it.