The earlier suggestion of a missing inverter seems to be the right thing to chase this evening. I was able to add an inverter and decode the first few characters on a scope. I get the expected DC1-CR-P-R-S sequence.
Thanks for the input on this. I'll reply back after I've had more time to hack at this. - Brian On Tuesday, August 25, 2015, Brian Inglis <[email protected]> wrote: > Hi, > You have too many 1s in your startup string compared to the expected > "PRS_10\r". > If the MCU clock is not 10Mhz then the integrated UART rates will be off, > which should produce framing errors, but do UARTs still detect and systems > report these nowadays, or just pass along garbled data? > Otherwise, garbled data is most often a result of inadequate pin contact, > if the connectors are not seated properly, or the pins or sockets are loose > in their shells. > Age and rough treatment can have that effect. > > "Internal hardware jumpers allow these pins to be configured as analog > outputs > to monitor the lamp intensity and varactor voltage for complete > compatibility > with the FRS." > Have you checked the jumpers in the manual Configuration Notes: > "Pin 4: TXD/PHOTO The default configuration uses this pin as an output for > RS-232 data. > Many system parameters (including the lamp intensity) may be monitored via > the RS-232 > interface. The function of this pin may be changed to an analog monitor > for the lamp > intensity by removing one resistor (R347) and installing a 10 kΩ resistor > for another (R348) > on the microcontroller PCB." > > On 2015-08-24 22:40, Brian M wrote: > >> I tried through the weekend, double and triple checking wiring and setup. >> I've tried the following methods of getting serial comms working: >> PRS10 -> Arduino Uno (with processor bypassed) -> USB Host >> PRS10 -> Level Shifter -> BBB UART >> PRS10 -> MAX232 -> USB Serial adapter >> >> Shortly after power is applied to the PRS10, I do get a string of >> characters. Believe it should be the model information. Instead I get: >> wy+VPgy >> >> I guess the good news is that this output appears consistent with each >> power cycle of the device. And I'm getting the same results through all >> the >> hookup methods I've tried. >> >> My minicom settings are for software flow control at 9600 8N1 - from what >> the manual states, this should be the right settings. I've tried screen as >> well - and get the same text. I went crazy trying several other rates and >> setting combinations. No luck. >> >> Maybe I've missed something obvious. >> >> I agree that getting comms going to the MCU are going to be an important >> step. How do people address this type of problem? Scope the serial and try >> to decode by hand? The 10Mhz to the MCU looks OK on a scope. Are there >> further steps people try after that? If nothing else I think there's some >> interesting stuff to learn here. I also wouldn't mind tearing out the >> electronics, determining if the lamp is good, and attempt to build from >> there. I don't know the datecode for the unit, the PCB is marked with a >> datecode suggesting 2003? I don't have the full case. I'm trying to assess >> what are reasonable next steps. How do I determine if the MCU is healthy? >> If the MCU is fried, how do I determine if I just need to squeeze a new >> MCU >> board in there? >> >> Thanks! I appreciate the input so far! >> - Brian >> >> PS - after looking again at the signal on the scope, it does seem like it >> is 9600 baud. ~100µS per bit. The data out on the MCU itself looks like >> what I saw on the main connector. >> >> On Sat, Aug 22, 2015 at 2:04 PM Mike Cook <[email protected]> wrote: >> >> >>> Le 22 août 2015 à 03:40, Bob Camp <[email protected]> a écrit : >>>> >>>> Hi >>>> >>>> On any microprocessor based gizmo, getting the micro running (again) is >>>> generally priority number one. It sets everything up and gives you the >>>> >>> diagnostic >>> >>>> info you need to go further. Garbled serial is better than none at all. >>>> >>> It suggests >>> >>>> something short of a total MCU death spiral … >>>> >>>> Bob >>>> >>>> On Aug 21, 2015, at 7:26 PM, Brian M <[email protected]> wrote: >>>>> >>>>> Dear list - >>>>> >>>>> I have come into possession of a for parts prs 10. I'd like to try to >>>>> repair this device. What I've noticed so far. Serial is garbled. (Even >>>>> >>>> at >>> >>>> varying baud rates). >>>>> >>>> >>> You don’t say how you are connecting to the Rb. The manual states: >>> "RS-232 data is sent to the host on pin 4, received from the host on pin >>> 7. The baud rate is >>> fixed at 9600 baud, 8 bits, no parity, with 1 start and 1 stop bit. No >>> DTR >>> or CTS controls are >>> used; rather, the XON/XOFF protocol has been implemented. The transmit >>> drive level is 0 >>> and 5 V, not the +/-12 V normally associated with RS-232. These levels >>> are >>> compatible with >>> most RS-232 line receivers, but does not require their use (a TTL >>> inverter >>> may be used >>> instead), hence simplifies the interface when used inside an instrument >>> at >>> the sacrifice of >>> degraded noise immunity over long lines." >>> >>> So make sure that you adhere to that. >>> >>> >>> Lamp isn't lit. >>>>> >>>> >>> What’s the date code. Early versions may be reaching EOL, though 20yrs id >>> quoted. >>> >>> Doesn't look great. I'd like to know >>>>> if anybody else has wandered down this path. What are common failure >>>>> >>>> modes? >>> >>>> Anything match up with what I describe? Voltages to check would be >>>>> >>>> helpful. >>> >>>> The 10MHz out looked okay on a scope. Haven't gone further yet. I >>>>> >>>> suspect >>> >>>> the crystal is fine. >>>>> >>>>> Thanks in advance. Happy hacking! >>>>> - Brian >>>>> >>>> _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
