The first  word is the bit-rate, and the third byte is the wait-state, they must change accordingly but not less than 1, I think.

The bit-rate has added 243 or 244 as a constant.


So 19200 baud would be more or less 251(00FBh, 01h), and 38400 would be 246(00F6h ,01h).

Midi(31250 baud) is between them, approximately 248(00F8h, 01h).

Some technical instrument must be used to probe this....

Ah, ok, now I understand you. I though that the third bit was only a pause.  The routine is not very efficient.

On the other side, 9600 bauds can still serve me to connect the ESP8266 module.

Thanks.

As you know I own two Enterprises with exactly the same add-ons, Saint 1MB internal Ram cards and  20Mhz CMos  Z80 processors with selectable speeds 4Mhz and 10Mhz.

If I connect them with the NET cable, they work as expected, but if I connect a stock EP128K to one of my modified computers at 4Mhz, the NET refuses to work at all.

As the Serial/Net is software driven, can it be the memory different speeds the problem with the connection?

Ok, thanks. I have read you about it before, but never though it would make a difference so big.

Usually the Wifi modules work at 3,3v TTL, so the optional LM1117 will feed the pull-ups and the module.


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I have made a simple Basic program to talk with a PC, I can write forward, but I have problems receiving.

The GET command gets stuck if there is no incoming character. So, before reading the serial port I test bit 5 of Z80 port 0B6h(182) for incoming data. But this port is a "general purpose" one, and is corrupted by other drivers that write on it.

Long time ago Zozo answered me a tip to overcome this situation, but I don't remember on what thread.

Please, can you kindly repeat me the way to properly read the "Status in" bit?

Thanks.