115200 Baud to 9600 Baud Translator

[ScottC]

I have been messing with this for a bit and no luck. I am using a 16F873A with UART. I see a burst of data on my scope, but PC does not see it. I also know that I have to invert the signal due to the nature of HSEROUT.

Is what I have code wise correct?

Any Ideas? I am using a 22.1184MHz Xtal. code is below.
Just using this as a test to see if I can get 115200 baud to work. Then I'll try to concour the above issue posted.


DEFINE OSC 20 ' 20MHz oscillator
DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 20h
DEFINE HSER_BAUD 115200
DEFINE HSER_SPBRG 2
TRISA = 0
TRISB = 0
TRISC = 0

PORTB.0 = 1

START:

HSerout ["12345",10]
Pause 1000

GoTo START
End

Thanks,

Scott

[Ceug2005]

try at lower speed
this what i use , not tested uper 9600

define OSC 20
DEFINE HSER_TXSTA 20h ' enable the transmit register
DEFINE HSER_BAUD 2400
.
.
.' +/-
HSEROUT [dec sign0,10,dec tempc0,13]

better to use an MAX 232 to conect at COMx

[Ingvar]

DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 24h
DEFINE HSER_SPBRG 11

[Ingvar]

.... and mode 97 should give 9600 baud with SEROUT2. However, you would probably do yourself a favour by switching to a 20MHz crystal since PBP likes that better, all timings will be correct. 115200 baud works quite well with 20MHz and HSEROUT.

DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 24h
DEFINE HSER_SPBRG 10

.... will give you 115200 with 20MHz.

[ScottC]

Well, at last I have success! Thanks to all who pitched in to make this happen. I adjusted the values in the define statements as suggested.

I am still using 22.1184 XTAL. Here is the test code below.

Thanks again.......

Scott


DEFINE OSC 20 ' 20MHz oscillator (22.1184MHz)
DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 24h
DEFINE HSER_BAUD 115200
DEFINE HSER_SPBRG 11
TRISA = 0
TRISB = 0
TRISC = 0

START:

HSerout ["HELLO"]
Pause 500

GoTo START
End

[ScottC]

Well, interesting. Now I am trying to take in the character at 9600 and resend at 115200. When I do this code below, my results are not what I want!

For example when I send the number 1, I receive an "a", send 2, I get an "f"
3 a "g", ect till I send 6, the sequence jumps to "n", "o".. Really strange.

I don't know if it is a timing issue or not???? Puzzled.

It was mentioned above that I could change the baud rate on the fly, How is that done? Could the issue be I have different baud rates on different pins, seems it should not matter. I'm lost..

ScottC

DEFINE OSC 20 ' 20MHz oscillator
DEFINE HSER_TXSTA 24h
DEFINE HSER_BAUD 115200 '115200 Baud Out
DEFINE HSER_SPBRG 11
DEFINE DEBUGIN_REG PORTB ' 9600,8,N,1 Serial In
DEFINE DEBUGIN_BIT 7
DEFINE DEBUG_BAUD 9600
DEFINE DEBUGIN_MODE 1
B7 VAR BYTE

'**********************************************

TRISA = 0
TRISB = %00000001
TRISC = 0

'********************************* READ SERIAL PORT

loop: While PORTB.7 = 1 'Wait for start bit
Wend

DebugIn [B7] ' B0 = input character
Pause 500

print: HSerout [B7]

GoTo loop ' Forever

[Bruce]

Are you're still using the 22.1184MHz crystal?

DEBUGIN bit timing is calculated for 20MHz with DEFINE OSC 20.