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[ried]

Hi all. Is the Programmable Frequency Generator (PFG) known to affect serial modem communications with LisaTerminal? I have a known good Lisa 2/5 working with one of James D's über cool ArcaneByte RS232 WiFiModems attached. It was working with at 1200 (or 2400 or 9600) baud in LisaTerminal just fine. But after I installed the PFG, when I type commands like “at” into the modem, it returns garbled text. Hmmm...

The modem is still online, according to LisaTerminal, and present in the system. But the characters returned by the modem seem to have been affected by the PFG. Has anyone heard of this before?

Thanks in advance.

[sigma7]

Is the Programmable Frequency Generator (PFG) known to affect serial modem communications

Yes, the PFG changes the 8530 SCC PCLK frequency from the Lisa's stock 4 MHz to the Mac's 3.672 MHz (this design decision was to support the Mac serial & terminal software that directly accesses the hardware), so software that is unaware of this change (ie. anything before MW+II) may be adversely affected. The MW+II  manual has a few entries in the index for SCC that can provide other details.

For most Lisa software, the Serial B port uses a separate crystal on the I/O Board to control the baud rate rather than PCLK. So software such as Lisa Terminal may work fine on Serial B with the PFG installed.

HTH

[ried]

Incredible that you know this, sigma7. Thank you. Indeed, I was using Serial A because Serial B has damaged traces due to previous battery corrosion.

Thank you again for the detailed explanation.

[patrick]

So you have to set Lisa Terminal to 1307 baud to get 1200 from the hardware. Someone has to patch the program code.