Hi and some Questions
Hi There,
I'm a newbie to this forums and to parallax products. I've been introduced to the propeller when I got myself a ybox2. So far I managed to create my own little propserial programmer and done minor changes to spin programs and loaded them onto the ybox. But next up I want to create my own little prototype board (I'm still planning to order a development board + prop plug, but it usually takes 4 weeks to get here in SA). From what I can gather in the schematic for the propeller demo board, I need to wire up a propeller with the eeprom.
(1) Does it have to be a 24LC256? I currently have a 24LC32. Can I use that instead ?
(2) Schematic shows a 5Mhz crystal, is that required ? Isn't there an internal oscillator of 80Mhz ?
(3) Any other parts I need to have to create a small working setup ?
I've got a project idea that I also want to turn into a contest entry for the propeller. This will be my first project so I hope I'm notrying too much too fast.
I'm a newbie to this forums and to parallax products. I've been introduced to the propeller when I got myself a ybox2. So far I managed to create my own little propserial programmer and done minor changes to spin programs and loaded them onto the ybox. But next up I want to create my own little prototype board (I'm still planning to order a development board + prop plug, but it usually takes 4 weeks to get here in SA). From what I can gather in the schematic for the propeller demo board, I need to wire up a propeller with the eeprom.
(1) Does it have to be a 24LC256? I currently have a 24LC32. Can I use that instead ?
(2) Schematic shows a 5Mhz crystal, is that required ? Isn't there an internal oscillator of 80Mhz ?
(3) Any other parts I need to have to create a small working setup ?
I've got a project idea that I also want to turn into a contest entry for the propeller. This will be my first project so I hope I'm notrying too much too fast.
Comments
2. A crystal is required for operation at 80MHz. There is an internal oscillator that runs at 12MHz.
3. Partswise, just the voltage regulators and caps, I believe. Plus power switch and reset circuitry.
Leon
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(1) hmm, but isn't the 24LC32 a 32k eeprom ? And the 24LC256 a 256k eemprom ?
(2) Only 5Mhz, or can it be other sizes as well ?
(3) Yup, I've got those [noparse]:)[/noparse]
Thanks for the help
2) The crystal can be anywhere in the range 4-8MHz as far as the crystal oscillator is concerned. The PLL (phase locked loop) multiplies this by 16 and feeds the result to a divider. There are taps at x16, x8, x4, x2, and x1. Officially, the PLL is only guaranteed up to 80MHz over the full temperature range and full power supply range, but people have successfully used 6MHz crystals for a PLL frequency of 96MHz.
The Propeller Tool ignores any EEPROM over 32K bytes, but several programs allow you to store programs and data anywhere in the EEPROM. FemtoBasic is one example. You can copy programs from the base 32K to other 32K "pages" (and run them) and you can store Basic programs above 32K in any attached EEPROM. There are Basic statements for reading and writing anywhere in EEPROM.
Post Edited (Mike Green) : 8/2/2008 7:09:01 PM GMT