Re: using the SCI with my transceiver

Started by gogosgeorge March 19, 2005

Guys,

just to let you know, the reason why I was asking questions before
about the SCI, and how everyone was telling me to read the manual,
On the cd, there was no section on the SCI, just the SPI!!! Thats
why I was getting confused. I looked at freescale, and found a
document which described the SCI well, so im reading up on that.

Ive gathered that SPI0 is used for RS232 connection to the pc, but
if I want to use SCI1, I can use either the 4 pin or 2 pin
connector, yes? Ive hooked up to the 2 pin connector, but im not
getting anything going through, yet my code seems fine. Am I using
the right pins? I noticed on the other 100 pins (come out on the
E128 development board with 2 small breadboards) There are pins
34/RXD1&32TXD1, and 32RXD2$31TXD1. do I use these instead? The
documentation doesnt give a good explaination of which pins are for
the SCI, and since im new to using the SCI apart from loading code
on my comp.......

It seems right using the 2 pins I mentioned earlier next to the 4
pins RS232 and the SCI0, but im just not getting anything going
there. does the register SCI1DRL and whatever data is in it
automatically go to these pins, once everything is initialised
properly?



On H1 header of Adapt9S12E128 are TXD1 (pin 32) and RXD1 (pin 34) for
use as SCI1. It is also connected to MAX3232 (voltage tranlator) via
jumper selection JB8.

If the RF module requires TTL signal then use Pin 32 and 34. If it
requires RS232 signal then use the 4 pin molex connector J2. Make
sure to check your connections are correct when you are making up the
cable and to include ground.

On H2 are TXD2 (pin 31) and RXD2 (pin 32). This is the SCI2 and the
pins are TTL signal only.

Exequiel --- In , "gogosgeorge" <ggogos@b...> wrote:
>
> Guys,
>
> just to let you know, the reason why I was asking questions before
> about the SCI, and how everyone was telling me to read the manual,
> On the cd, there was no section on the SCI, just the SPI!!! Thats
> why I was getting confused. I looked at freescale, and found a
> document which described the SCI well, so im reading up on that.
>
> Ive gathered that SPI0 is used for RS232 connection to the pc, but
> if I want to use SCI1, I can use either the 4 pin or 2 pin
> connector, yes? Ive hooked up to the 2 pin connector, but im not
> getting anything going through, yet my code seems fine. Am I using
> the right pins? I noticed on the other 100 pins (come out on the
> E128 development board with 2 small breadboards) There are pins
> 34/RXD1&32TXD1, and 32RXD2$31TXD1. do I use these instead? The
> documentation doesnt give a good explaination of which pins are for
> the SCI, and since im new to using the SCI apart from loading code
> on my comp.......
>
> It seems right using the 2 pins I mentioned earlier next to the 4
> pins RS232 and the SCI0, but im just not getting anything going
> there. does the register SCI1DRL and whatever data is in it
> automatically go to these pins, once everything is initialised
> properly?



What is JB8 (Max3232) used for? does it need to be connected here first and then to TXD1 and RXD1?
George Gogos
Undergraduate
BACHELOR OF ENGINEERING(Computronics/Electronics)
Deakin University, Australia ----- Original Message -----
From: zeta_alpha2002
To:
Sent: Sunday, March 20, 2005 4:27 AM
Subject: [68HC12] Re: using the SCI with my transceiver
On H1 header of Adapt9S12E128 are TXD1 (pin 32) and RXD1 (pin 34) for
use as SCI1. It is also connected to MAX3232 (voltage tranlator) via
jumper selection JB8.

If the RF module requires TTL signal then use Pin 32 and 34. If it
requires RS232 signal then use the 4 pin molex connector J2. Make
sure to check your connections are correct when you are making up the
cable and to include ground.

On H2 are TXD2 (pin 31) and RXD2 (pin 32). This is the SCI2 and the
pins are TTL signal only.

Exequiel --- In , "gogosgeorge" <ggogos@b...> wrote:
>
> Guys,
>
> just to let you know, the reason why I was asking questions before
> about the SCI, and how everyone was telling me to read the manual,
> On the cd, there was no section on the SCI, just the SPI!!! Thats
> why I was getting confused. I looked at freescale, and found a
> document which described the SCI well, so im reading up on that.
>
> Ive gathered that SPI0 is used for RS232 connection to the pc, but
> if I want to use SCI1, I can use either the 4 pin or 2 pin
> connector, yes? Ive hooked up to the 2 pin connector, but im not
> getting anything going through, yet my code seems fine. Am I using
> the right pins? I noticed on the other 100 pins (come out on the
> E128 development board with 2 small breadboards) There are pins
> 34/RXD1&32TXD1, and 32RXD2$31TXD1. do I use these instead? The
> documentation doesnt give a good explaination of which pins are for
> the SCI, and since im new to using the SCI apart from loading code
> on my comp.......
>
> It seems right using the 2 pins I mentioned earlier next to the 4
> pins RS232 and the SCI0, but im just not getting anything going
> there. does the register SCI1DRL and whatever data is in it
> automatically go to these pins, once everything is initialised
> properly?

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Re[2]: [68HC12] Re: using the SCI with my transceiver
Re: using the SCI with my transceiver
Saturday, March 19, 2005, 5:39:02 PM, you wrote:

GB> What is JB8 (Max3232) used for? does it need to be connected
GB> here first and then to TXD1 and RXD1?

Serial communications from a PC (or similar) use nominally +15/-15
volt signals. This needs to be level shifted in order to work with
0/5V or 0/3.3V boards. The MAX chip does this level shifting in both
directions.

You don't need it for your RF module most likely. I'd expect that it
wants normal 0/5V or 0/3.3V signals.

Aaron



> What is JB8 (Max3232) used for?

Look at the schematic diagram to tell you how it is connected. That
will answer your question.

>does it need to be connected here first and then to TXD1 and RXD1?

The RF module, does it need TTL/CMOS signal or RS232 signal. The
previous email has already answered the above question. --- In , "George \(Bigpond\)" <ggogos@b...> wrote:
> What is JB8 (Max3232) used for? does it need to be connected here
first and then to TXD1 and RXD1?
> George Gogos
> Undergraduate
> BACHELOR OF ENGINEERING(Computronics/Electronics)
> Deakin University, Australia > ----- Original Message -----
> From: zeta_alpha2002
> To:
> Sent: Sunday, March 20, 2005 4:27 AM
> Subject: [68HC12] Re: using the SCI with my transceiver >
> On H1 header of Adapt9S12E128 are TXD1 (pin 32) and RXD1 (pin 34) for
> use as SCI1. It is also connected to MAX3232 (voltage tranlator) via
> jumper selection JB8.
>
> If the RF module requires TTL signal then use Pin 32 and 34. If it
> requires RS232 signal then use the 4 pin molex connector J2. Make
> sure to check your connections are correct when you are making up the
> cable and to include ground.
>
> On H2 are TXD2 (pin 31) and RXD2 (pin 32). This is the SCI2 and the
> pins are TTL signal only.
>
> Exequiel > --- In , "gogosgeorge" <ggogos@b...> wrote:
> >
> > Guys,
> >
> > just to let you know, the reason why I was asking questions before
> > about the SCI, and how everyone was telling me to read the manual,
> > On the cd, there was no section on the SCI, just the SPI!!! Thats
> > why I was getting confused. I looked at freescale, and found a
> > document which described the SCI well, so im reading up on that.
> >
> > Ive gathered that SPI0 is used for RS232 connection to the pc, but
> > if I want to use SCI1, I can use either the 4 pin or 2 pin
> > connector, yes? Ive hooked up to the 2 pin connector, but im not
> > getting anything going through, yet my code seems fine. Am I using
> > the right pins? I noticed on the other 100 pins (come out on the
> > E128 development board with 2 small breadboards) There are pins
> > 34/RXD1&32TXD1, and 32RXD2$31TXD1. do I use these instead? The
> > documentation doesnt give a good explaination of which pins are for
> > the SCI, and since im new to using the SCI apart from loading code
> > on my comp.......
> >
> > It seems right using the 2 pins I mentioned earlier next to the 4
> > pins RS232 and the SCI0, but im just not getting anything going
> > there. does the register SCI1DRL and whatever data is in it
> > automatically go to these pins, once everything is initialised
> > properly?
------
> Yahoo! Groups Links
>
> a.. To >
>




--- In , aaron <spamtest@s...> wrote:
> Saturday, March 19, 2005, 5:39:02 PM, you wrote:
>
> GB> What is JB8 (Max3232) used for? does it need to be connected
> GB> here first and then to TXD1 and RXD1?
>
> Serial communications from a PC (or similar) use nominally +15/-15
> volt signals. This needs to be level shifted in order to work with
> 0/5V or 0/3.3V boards. The MAX chip does this level shifting in both
> directions.

Don't forget if you have +/-12V or so available three transitors will do the same as the Max a lot cheaper.

Cheers,

Theo



The RF only needs ttl signals, so I guess ill be usin SCI1, with pins TXD1(32) & RXD1(34) true? George Gogos
Undergraduate
BACHELOR OF ENGINEERING(Computronics/Electronics)
Deakin University, Australia ----- Original Message -----
From: theobee00
To:
Sent: Sunday, March 20, 2005 5:17 PM
Subject: [68HC12] Re: using the SCI with my transceiver
--- In , aaron <spamtest@s...> wrote:
> Saturday, March 19, 2005, 5:39:02 PM, you wrote:
>
> GB> What is JB8 (Max3232) used for? does it need to be connected
> GB> here first and then to TXD1 and RXD1?
>
> Serial communications from a PC (or similar) use nominally +15/-15
> volt signals. This needs to be level shifted in order to work with
> 0/5V or 0/3.3V boards. The MAX chip does this level shifting in both
> directions.

Don't forget if you have +/-12V or so available three transitors will do the same as the Max a lot cheaper.

Cheers,

Theo

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