Connecting a 68882
Hello,
has anyone considered to connect a 68882-FPU (at 50MHz) to the Prop?
I know that there is a "Soft"-FPU which takes a cog to calculate with Float-Numbers, but i am planning a Project
where i need as much cogs i can get![smile.gif](http://forums.parallax.com/images/smilies/smile.gif)
I think that the biggest Problem will be that the 68882 needs TTL-Voltage-Signals (0-5Volt) and the Prop normally
runs at 3,3 Volt... (i read already the thread about interfacing 5V-Signals to the Prop, but this handles only one
side of the Problem because 5Volts are needed as Input and Output - does anyone know if there is a bus-driver-iC
which can "translate" between the Prop and the 68882?)
Greets,
Mathias
has anyone considered to connect a 68882-FPU (at 50MHz) to the Prop?
I know that there is a "Soft"-FPU which takes a cog to calculate with Float-Numbers, but i am planning a Project
where i need as much cogs i can get
![smile.gif](http://forums.parallax.com/images/smilies/smile.gif)
I think that the biggest Problem will be that the 68882 needs TTL-Voltage-Signals (0-5Volt) and the Prop normally
runs at 3,3 Volt... (i read already the thread about interfacing 5V-Signals to the Prop, but this handles only one
side of the Problem because 5Volts are needed as Input and Output - does anyone know if there is a bus-driver-iC
which can "translate" between the Prop and the 68882?)
Greets,
Mathias
Comments
focus.ti.com/docs/prod/folders/print/sn74lvc4245a.html
8 Bit CMOS/TTL Bus Transceiver for dual power supply. 1$ or so each.
This manual provides a bit of information and some circuits to connect the 68882 to the 68k processors, it does not seem very complicated, not more than a T6963 LCD controller, programming is something else:
www.freescale.com/files/32bit/doc/fact_sheet/BR509.pdf
There is a register map on page 12, very light on details. May be some info survived from the Amiga days, were it was connected to a 68000 in memory map mode. That could give you a hint to how to program it. If you know how to please enlighten us. I am just curious.
edit: for comment con complexity.
@Turican: Sorry for my imputation. But there is a lot more in this thread than "serial resistors". I remember, I gave a link to a comprehensive "Sparkfun Tutorial" about this matter. Most interesting using a diode in combination with a pull-up resistor.... But when neeeding really fast AND bidirectional connections, professional level shifters might be best...
I have a very good book from my "old" days when i was designing and programming hardware/software-stuff for the Amiga-Computers, its named "MICROPROCESSOR SYSTEMS DESIGN, 68000 Hardware, Software and Interfacing" - its a very good book about building complete 68k-based systems from the 68000 to the 68060 even with the MMU and FPU-things. So based on this informations about the hardware AND (what is even more important to me) the software i want to connect the 68882 to the prop.
I will have a look at the CMOS-TTL-Bus-Transciver, maybe it is suitable for this application!
Thanx for you replies!