Propeller vs Basic STAMP BS2P40
Hi all,
I was using Basic Stamp BS2p40 for my project. For one of the task, I needed to load the controller with 10Kbits. But, max RAM capacity is 128byte.
Now, I would like to look for a higher version of controllers in parallax. That is the reason why I opted for Propeller.
I would like to know if propeller can meet my requirements:
My spec requirements:
32 I/O
Serial in/out thro RS232
I2C communication support to external devices
Max RAM size
USB interface
10/100base ethernet interface
ADC/DAC
from my search on the manuals, Iam not clear about the I2C communication support for external devices. There is an optional pins for EEPROM. I would like to know If I can use for other devices say an fpga.
I was using Basic Stamp BS2p40 for my project. For one of the task, I needed to load the controller with 10Kbits. But, max RAM capacity is 128byte.
Now, I would like to look for a higher version of controllers in parallax. That is the reason why I opted for Propeller.
I would like to know if propeller can meet my requirements:
My spec requirements:
32 I/O
Serial in/out thro RS232
I2C communication support to external devices
Max RAM size
USB interface
10/100base ethernet interface
ADC/DAC
from my search on the manuals, Iam not clear about the I2C communication support for external devices. There is an optional pins for EEPROM. I would like to know If I can use for other devices say an fpga.
Comments
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I am 1010, so be surprised!
It can do serial input/output through any of the 32 pins. Typically one (of eight) cog(s) can provide a full duplex serial channel up to 230KBaud.
It can behave as an I2C master on one or more pairs of I/O pins. Speed is over 100KHz, but less than 400KHz.
There are 32Kbytes of general purpose RAM which also contains part of your program. There's an additional 2Kbyte per cog of memory that's not accessable outside of the cog and is used for assembly programming and part of the data used by an assembly program.
The Propeller itself doesn't have a USB interface, but most development boards have a USB to serial adapter. There has been some experimentation in writing a USB driver for the Propeller, but it's limited in capability.
The Propeller doesn't have an Ethernet interface. Several people have experimented with a stack for an external Ethernet interface. I believe it can do FTP and UDP transfers.
The Propeller can do multiple channels of ADC using a Delta-Sigma conversion method. This requires two resistors and two capacitors attached closely to two I/O pins. The conversion speed depends on the resolution required. DAC is done using PWM and a resistor/capacitor filter.
(Note that a 10BaseT device will work fine in a faster network since most ports are auto negotiating)
If you want RS232 (not just uart) than you will need an external circuit to get to the required voltages.
hippy has recently released a I2C slave driver. The link is in the April edition of the prop magazine.
The Propeller can do low speed usb with 3 external resistors. I've got it emulating a USB keyboard, and also a CDC-ACM serial port (good for about 8KB/sec full-duplex). I've been playing with using it as a joystick and toying with a few other bits 'n bobs, but the CDC-ACM serial port has been running 24/7 since Nov on my AC thermostat connected to one of my linux servers.
Plenty of memory, but depending on what you want to do, low speed USB may not be fast enough.
One day I'll finish it off and get it packaged for the OBEX, but I need to do more testing with the Windows USB stack first (and I detest Windows)..
Brad