HSEROUT to LCD with 16F887

[Archangel]

So, take your project, figure out what it's outputting, take the device you're talking to, figure out what it wants, take your project again and change it to match...

According to his post <b>#3</b> his serial LCD is accepting N9600, he need to read the data sheet for that device and change it to Txxxx to use HSEROUT. Most likely it requires moving a shorting block on a three pin header.

[menta]

from the LCD data sheet:
"Serial input...............RS-232, or inverted TTL/CMOS, 2400 or 9600, N81"
http://www.seetron.com/pdf/bpi_bpk.pdf

I do not see any documentation beside changing the speed from 2400 to 9600 using the SW on its back.

[skimask]

from the LCD data sheet:
"Serial input...............RS-232, or inverted TTL/CMOS, 2400 or 9600, N81"
http://www.seetron.com/pdf/bpi_bpk.pdf

I do not see any documentation beside changing the speed from 2400 to 9600 using the SW on its back.

Exactly...so...read it again...the backpack takes RS232 or inverted TTL/CMOS, which if you have read my last post completely and understood it, you would know that from a logic level standpoint (not a voltage level) RS232 = inverted TTL.

Therefore, without any external hardware, only one subset of the PBP serial format communication commands can successfully communicate with this LCD module.

So, to quote myself once again...
SERIN/SERIN2/SEROUT/SEROUT2/DEBUG/DEBUGIN - software driven
You can set the modes, normal, inverted, whatever. Totally and completely driven by software. You can emulate the logical levels of standard RS232, but not the actual voltages present in standard RS232 (i.e. inverted)...or... You can emulate the logic levels and voltage levels of what is sometimes called TTL-RS232 (i.e. normal)...

HSERIN/HSERIN2/HSEROUT/HSEROUT2 - hardware driven
You can NOT change the modes here, only the baud rates, bits per character, and a few other parameters. This is completely driven by the hardware inside the PIC. There is NO inversion anywhere inside the PIC, whether it be thru hardware or software.

In short:
HSERxxx - needs a MAX232 device if talking to an RS232 compliant device. May or may not need a MAX232 type device if talking to any other type device (i.e. directly to another PIC. What drives a Serial LCD? Anyone?).

SERxxx - may or may not need a MAX232 type device depending on the application.

[skimask]

According to his post <b>#3</b> his serial LCD is accepting N9600, he need to read the data sheet for that device and change it to Txxxx to use HSEROUT. Most likely it requires moving a shorting block on a three pin header.

Can't do that with this particular module. Only takes RS232 (inverted) inputs.

[menta]

Thanks....

[Darrel Taylor]

You can use a single transistor and a couple resistors to invert the signal from the USART.

You don't have to go with a full MAX232.
DT