Do you need to run your 8051 TTL signals through the RS232 interface ? I suppose if it helps resolve any line polarity issues. As the "relay switch" will only be switching logic level signals it can be done without relays using simple logic gates. It would be possible to do it so any of the three sources could be used ( all connected simultaneously ), providing only one source were communicating at a time.
1. The USB will be used to program the chip directly from propeller tool
2. If USB is non viable for whatever reason, DB9 serial can be used in lieu of USB. Also serial can be used for terminal emulator as needed via max232 interface if switched into that mode
3. If two options are not in play, then 3 pin header is switched in for incoming data streams from 8051 to display on VGA output whatever serial buffer data is sent. The data from the 8051 is strictly TTL (0-5V). To go to terminal from that app max232 for terminal read (trying to remove that via the propeller module).
8051 > serial data out > VGA write to CRT/LCD on screen > ultimately replace terminal > no computer neeeded to see 8051 datastreams. [noparse][[/noparse]this is primary function of propeller module].
Option 3 is primary function, 1 and 2 are used for field programming module as updates arrise and/or allow serial connection to a computer if needed.
Does that make sense?????
I will only be switching the RXD/TXD that connects to the propeller chip, all 3 of the options will always be active, but only one at a time (user button requested) will determine what mode it will be in.
Post Edited (kittmaster) : 12/10/2007 5:53:24 PM GMT
How many of these do you plan on making on your CNC machine? You could always design a separate carrier for the SSOP part on a thin PCB and then solder the PCB straight onto your CNCed board. You could also go with the other methods provided on this forum. I especially like the inexpensive carrier/breakout boards that have been posted.
Using a carrier board may be more expensive, but a PIC solution would require you to go through more things like obtaining a USB VID/PID and making sure the Microchip provided example USB->serial code will work. Don't forget that your PIC usb solution must implement the correct timing required for the propeller reset/program operations. There are even some commercial serial->rs232 adapters that don't get this right, and hence don't work with many microcontroller bootloading applications.
I've got close to 110 people interested in the aspect of the project that I sell. So I would have to hand solder 110 of these things.....LOL.
I totally agree that the dip breakout can be soldered, but it then looks like an afterthought instead of a straight design.
I do all my own assembly and soldering to keep the cost down on production pcbs. I'll be compiling a schematic and post up some pics to see if anyone can critique it to ensure a proper setup. Looks pretty straight forward though
With flux, desoldering braid and a steady hand, soldering SOP pitch pins (SOP, SSOP, TSSOP) are not that difficult. If you want to see some online tutorials I can dig some up for you.
Comments
1. The USB will be used to program the chip directly from propeller tool
2. If USB is non viable for whatever reason, DB9 serial can be used in lieu of USB. Also serial can be used for terminal emulator as needed via max232 interface if switched into that mode
3. If two options are not in play, then 3 pin header is switched in for incoming data streams from 8051 to display on VGA output whatever serial buffer data is sent. The data from the 8051 is strictly TTL (0-5V). To go to terminal from that app max232 for terminal read (trying to remove that via the propeller module).
8051 > serial data out > VGA write to CRT/LCD on screen > ultimately replace terminal > no computer neeeded to see 8051 datastreams. [noparse][[/noparse]this is primary function of propeller module].
Option 3 is primary function, 1 and 2 are used for field programming module as updates arrise and/or allow serial connection to a computer if needed.
Does that make sense?????
I will only be switching the RXD/TXD that connects to the propeller chip, all 3 of the options will always be active, but only one at a time (user button requested) will determine what mode it will be in.
Post Edited (kittmaster) : 12/10/2007 5:53:24 PM GMT
Using a carrier board may be more expensive, but a PIC solution would require you to go through more things like obtaining a USB VID/PID and making sure the Microchip provided example USB->serial code will work. Don't forget that your PIC usb solution must implement the correct timing required for the propeller reset/program operations. There are even some commercial serial->rs232 adapters that don't get this right, and hence don't work with many microcontroller bootloading applications.
Harrison
I totally agree that the dip breakout can be soldered, but it then looks like an afterthought instead of a straight design.
I do all my own assembly and soldering to keep the cost down on production pcbs. I'll be compiling a schematic and post up some pics to see if anyone can critique it to ensure a proper setup. Looks pretty straight forward though
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Paul Baker
Propeller Applications Engineer
Parallax, Inc.
Post Edited (Paul Baker (Parallax)) : 12/10/2007 10:30:16 PM GMT
I've soldered those styles in the past.....just not very much fun.
Thank you for the offer.....[noparse]:)[/noparse]