BS2 Chip on home board giving funny signal to EPROM???
Steel
Posts: 313
Has anybody come across this?
I have a home-brewed board wired up right now.· The Stamp is not responding to PBasic.· I am using a comport program, and sending the BS2 "A5" as a practice signal.
I am suspecting an issue with the BS2/EPROM interface.
When I probe Pin6 on the interpretor chip, it is idle.· (should see signal)
When I probe Pin7 on the interpretor chip, I get a Constant clock pulse (0V-5V)at about 333 kHz.
The EPROM is a STMicroElectronics M24C16
http://www.st.com/stonline/books/pdf/docs/5067.pdf
Pin1 - Pin4 tied low.· Pin7 tied low
Pin8 connects to 4.7k resistor which connects to pin5.
Pin5 connects to pin6 on interpretor chip
Pin6 connects to pin7 on interpretor chip.
on the interpretor chip:
-the resonator is clean, the reset line is high
-reset line is high:· Drops briefly when PBASIC sends command.
-Pin8 on the BS2 interpretor chip is showing the signal (occasionally).· The lines are naturally high, the "A5" signal is visible, and the line returns to high when idle.
-Pin9 is not showing a signal
Has anybody come across this behavior?
·
I have a home-brewed board wired up right now.· The Stamp is not responding to PBasic.· I am using a comport program, and sending the BS2 "A5" as a practice signal.
I am suspecting an issue with the BS2/EPROM interface.
When I probe Pin6 on the interpretor chip, it is idle.· (should see signal)
When I probe Pin7 on the interpretor chip, I get a Constant clock pulse (0V-5V)at about 333 kHz.
The EPROM is a STMicroElectronics M24C16
http://www.st.com/stonline/books/pdf/docs/5067.pdf
Pin1 - Pin4 tied low.· Pin7 tied low
Pin8 connects to 4.7k resistor which connects to pin5.
Pin5 connects to pin6 on interpretor chip
Pin6 connects to pin7 on interpretor chip.
on the interpretor chip:
-the resonator is clean, the reset line is high
-reset line is high:· Drops briefly when PBASIC sends command.
-Pin8 on the BS2 interpretor chip is showing the signal (occasionally).· The lines are naturally high, the "A5" signal is visible, and the line returns to high when idle.
-Pin9 is not showing a signal
Has anybody come across this behavior?
·
Comments
Have you downloaded the Parallax OEM board schematic? And does your wiring match it?
Do you perhaps need pull-ups on the EEPROM? On the RESET line?
Did you buy your "interpreter" chip from Parallax? (I'm assuming you did, it sounds like it anyway)
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Because even though you don't get your answer directly, the replies motivate you in new ways.
The issue is that I had Pin8 of my eprom connected to the Resistor to pin5 BUUUUT I did not connect Pin8 to VCC.
Thanks for your reply, Allan and Chris