SEROUT being unreliable

[Kamikaze47]

Hi,

I'm having a problem with SEROUT. When I use HSEROUT it works perfectly, but when I use SEROUT or SEROUT2 I get errors in the data. I'd guess that about 5% of the characters are corrupted.

PIC: 18F4550
Clock: 48Mhz

HSEROUT code (works):

DEFINE HSER_TXSTA  24h
DEFINE HSER_RCSTA  90h
DEFINE HSER_BAUD   2400
DEFINE HSER_SPBRG  25
DEFINE HSER_BITS   8

HSEROUT ["This is a test."]

SEROUT code (5% of characters are corrupted):

SEROUT PORTB.3,0,["This is a test."]

Does anyone have any ideas as to why this would be happening?

[skimask]

I'm having a problem with SEROUT. When I use HSEROUT it works perfectly, but when I use SEROUT or SEROUT2 I get errors in the data. I'd guess that about 5% of the characters are corrupted.
PIC: 18F4550
Clock: 48Mhz
Does anyone have any ideas as to why this would be happening?

Cable straight from PIC to PC?
DEFINE OSC 48 used?
Do higher/slower baud rates work better/worse?

[falingtrea]

HSERIN and HSEROUT use the built in UART of some PIC parts to communicate. SERIN(2) and SEROUT(2) I believe are software emulations of a UART. At the clock speed you are running at I would probably be better to use the UART. The software emulation uses up too much of the PIC resources anyway.

[Kamikaze47]

Its a cable going directly to a DoubleTalk text-to-speech board.

I am defining OSC 48 yes.

I initially started at 9600 baud, and lowered to 2400 to see if that would fix it, which it didn't.

When i use SEROUT or SEROUT2 the corrupted characters cause the text-to-speech to mispronounce the words. HSEROUT is flawless. No issues at all.

The reason I need this is I need at least 2 serial outputs and this PIC only has 1 hardware USART.

[skimask]

The reason I need this is I need at least 2 serial outputs and this PIC only has 1 hardware USART.

Semi-silly idea for you...but might be easier than you think. Might even be able to write a macro to handle the switching for you...
Use the HSEROUT for your serial out as you've already planned it out...
Get your hands on a couple of AND gates, or whatever works...
Use another PIC pin or two as STEERING LOGIC.

[Kamikaze47]

Semi-silly idea for you...but might be easier than you think. Might even be able to write a macro to handle the switching for you...
Use the HSEROUT for your serial out as you've already planned it out...
Get your hands on a couple of AND gates, or whatever works...
Use another PIC pin or two as STEERING LOGIC.

Thats a pretty good idea.

[skimask]

Thats a pretty good idea.

Well, heck, glad I could help...
Generally I'm useless
Does your program have any interrupts running in it?

[Kamikaze47]

Actually, i do have 3 interrupts in this program. Maybe SEROUT is getting interrupted and thats messing with the data.

I'm gonna try disabling the interrupts while I run SEROUT... Not the best long term solution as It wouldnt be good to miss one of those interrupt events, but its worth a try to see if thats whats causing my problem.

[Kamikaze47]

I just lowered the SEROUT2 baud to 600 and it works by the look of it. But that is much too slow and it holds up my program.

With a 48Mhz clock, i'm not sure why it would struggle with 9600 baud, let alone 2400.

[b1arrk5]

With the Double-Talk chipset you can pre-record your audio, and just send the address for the phrase that you want to play. You might be able to send out the bytes between interrupts. If I remember correctly, (I don't have my book with me here,) you have to end the play address with a 13, and the chipset will play whatever is stored at that address as soon as it sees the 13. This way you would only need to send out a few bytes each time.

Jerry.