| View previous topic :: View next topic |
| Author |
Message |
BigEd
Joined: 11 Dec 2008
Posts: 397
Location: England
|
 Posted: Thu Jan 14, 2010 8:34 pm Post subject: 6502 on propeller: NES pacman |
 |
|
Potatohead on the AtariAge forums brings this to our attention: Darryl Biggar
fixed and incorporated Eric Ball's 6502 emulation into a NES emulator which runs pacman.
Most amusing comment:
| Code: |
' TODO decimal mode
|
(perhaps I'm easily amused: I know decimal mode is difficult to get right.)
Eric adds this summary of what Propeller is (Besides a 5v (*) 40-pin DIP):
| Quote: | Just to elaborate on Propeller RAM - each 32bit processing core has 2K (496x32bit) of private RAM for code and local data/registers. There is 32K of on chip shared RAM used for shared data and SPIN bytecode. Access to the shared RAM is slower 4-8 times slower than private RAM. The Propeller does not have an external memory bus architecture - only 32 GPIO pins. An external memory can be attached, but it cannot be used to store code directly. The RAMBlade is a design with a 512Kx8 SRAM connected directly to the Propeller.
|
This succesful emulation of 6502 is not to be confused with the earlier topic where a 6502 system uses a propeller for glue (and bootstrapping)
Edit: I stand corrected, chip is 3.3v but interfacing with 5v not too difficult.
Last edited by BigEd on Fri Jan 15, 2010 4:17 am; edited 1 time in total |
|
| Back to top |
|
 |
OwenS
Joined: 26 Jul 2007
Posts: 91
|
| Posted: Thu Jan 14, 2010 10:56 pm Post subject: |
|
|
The Propeller is 3.3v. The Propeller II is going to be 3.3v IO with 1.8v core.
The silicon process it's built in doesn't permit 5v logic. For low speed signals, serial resistors will, in combination with the Propeller's clamp diodes, provide suitable input level translation (This is officially supported) |
|
| Back to top |
|
|
BigEd
Joined: 11 Dec 2008
Posts: 397
Location: England
|
| Posted: Fri Jan 15, 2010 3:56 am Post subject: |
|
|
Sorry, my mistake!
Looking more carefully at the 6502 laptop project I see it shows 5v supplies for all the non-propeller chips, and uses 1k series resistors, but isn't explicit about powering the propeller at 3.3v
There's a thread about interfacing with 5v here. |
|
| Back to top |
|
|
|
