On (22 Jan 95) [EMAIL PROTECTED] wrote to All... Hi Si!
> From: Simon Cooke <[EMAIL PROTECTED]> > Date: Sun, 22 Jan 1995 22:19:14 +0000 (GMT) > Hi Jonathan... we've been having very odd results from doing the mod you > suggested.... Errr do you mean me? or was there someone else same name spelt differently? > At the moment it seems that to get it to work you have to do your mod but > leave the ground line uncut. (Or have we misunderstood the mod???) Assuming you mean my original mod from year(s) back then you shouldn't touch the ground line! The MOD is simply to reduce the +Vcc to the UART ONLY by cutting the +Vcc track between the decoupling disc-ceramic capacitor and the UART and patching a *forward* biased general-purpose silicon diode from the +Vcc solder-pad of the disc-ceramic previously mentioned and the +Vcc pin of the UART. This just happens to reduce the UART's logic-zero output to below the critical point at which it previosly gave false 1's. (Just one of those flashes of inspiration that worked first time;-)) I did *TRY* connecting the other SAM-BUS 0V to the COMMS-INT 0V circuit and I believe it helped when the diode fix wasn't used but wasn't 100% reliable, whilst the diode fix did make it 100% reliable with or without any other 0V extras:-) Oh Si, An alternative to using FiFoFull UART interupt you *could* do RxRDY and whilst in it's ISR Disable all other interupts and sit there reading the Fifo until empty or software ring-buffer fills.... If Ring-buffer full occours first then try issuing a UART command to de-assert MPO manually then hopfully there'll be enough Fifo positions left for the sender to react and stop sending and not lose chars ie a PeeCee Null-modem sender, Modems are ok as they honour RTS flow-control properly. It should overcome the interupt latency forced on us by having to determine who caused the interupt via the asic status reg and then the UART ISR... If the above works then it might allow SAM to receive at 115200baud I mentioned in a previous message about commix;-) Regards Johnathan. ... Finagle's first Law: If an experiment works, something has gone wrong. -- |Fidonet: Johnathan Taylor 2:2501/307.9 |Internet: [EMAIL PROTECTED] | | Standard disclaimer: The views of this user are strictly his own.
