On Sat, Feb 19, 2011 at 10:40 AM, Tony Firshman <[email protected]> wrote:
> BryanHorstmann wrote, on 19/Feb/11 11:14 | Feb19: > <printing problems snipped> > > >>> Revisiting this subject >> >> Recently I happened to see a reference to the Super Gold Card having an >> 8049 chip which handles the serial port (amongst other jobs). It could >> therefore. be the SGC which is faulty, as the original QL is now working >> OK with a Trump card, and the battery on the SGC is down. >> > It doesn't. SGC has a parallel port which is fault free (as far as I > know!). SGC does *nothing* to the QLs serial ports as far as I know. > Maybe as the QL is running much faster it is simply throwing up a handshake > issue. Try really really low speeds to test. > > Serial output (incl printing) is done by the QLs 8302 including handshaking > up to 19200bps. The QL 8049 is for serial input and is heavily bugged. The > practical max was often less than 4800bps. Also if a handshake was needed > when the QL was making a sound, it got forgotten for a few chrs. The input > was then out of phase, and *only* a power down (not a reset) would cure. > There were a number of other bugs. Hermes (an 8749 to replace the 8049) > sorted out those bugs and increased serial input to around 14400 (nominal > 19200). > > superHermes also sorted out the bugs, increased the QLs serial ports to a > full 19200 both ways, and added ser3 up to 430800. The practical maximum > input though, even with SGC, is somewhere above 56k, as Adrian Ives has > commented on with his USBwiz devbelopment 115200bps setting is used as long > as handshaking is enabled. Output though is probably much higher than > 115200 but untested. > The limitation in all cases is QL (and destination) processing power and > not superHermes. > > Tony, Could you educate us a little on how the 8049 (which is a standard Intel microcontroller) gets its program? How is an 8749 different from an 8049? Does it run the same program the 8049 runs but better, or a different program provided by the *Hermes? I've often thought of 8049 and 8749 as not interchangeable, but I don't remember why. I vaguely recall the 8749 had more functions and internal memory, and could clock faster than the 8049's 11MHz, but I do not trust my memory on this. Will look it up later. Anything you say may be taken and used to improve the wiki ;) Dave _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
