problem communicating to LPC 2106 on Windows

Started by dJsLiM November 23, 2006
Hi everyone,

I'm a complete newbie to LPC development. I got the Olimex LPC MT 2106
board with a variable voltage powersupply from.

I have set the power supply to 9V and plugged it into the board. When
I hook the power I see that the top line of the LCD display gets
darker. No other indication of power seems visible.

I'm using a normal DB9 serial cable to connect the board to my PC on
COM 1.

I have located the jumper so that the two BSL pins are connected
together. The two pins below the BSL do not have jumpers on them as I
removed it.

I got the Philips 2000 flash utility then set it to LPC 2106. I got a
simple led.hex program online for trial.

When I try to flah using "Upload to Flash" the utility it prompts me
to reset the board. So I hit the reset switch and then hit "ok".

The utility then stalls for a bit and pops open an alert box saying
"Cannot communicate with test board!"

Can anyone point me in the right direction?

My apologies in advance if this question has been asked previsouly. I
tried doing a search but perhaps my choice of keywords is poor.

thanks for your help!

slim

An Engineer's Guide to the LPC2100 Series

Hi,

>From looking at the schematic:

The MT2106 board is intended for 9V AC operation, if you have used
9VDC it should still work.

The other three, two pin jumpers are:
DALLAS - to connect a one-wire device
DEBUG that enables the JTAG interface at boot when shoreted.
FREQ is connected to one of the ports - do not short this jumper.

To use the LPC Flash Tool BSL should be shorted at boot. It should
be removed for normal operation.
>From experience:

The LCD probable needs its contrast adjusting, this is done with a
small screwdriver by turning the small preset LCD_TR

Other than that, you are doing the right thing. Connect the DB9
connector to your PC, select the correct COM port in FlashTool and
away you go.

If it still does not work, you can use Hyperterminal (or any serial
terminal) to talk to the flash loader in the chip, I can explain how
to do this if you like?

The only things that can stop the flash loader working are:
Bad crystal or bad crystal load capacitors.
BSL jumper not working
Internal power supply fault

There are some simple tests you can do to prove that these are
working correctly.

Do you have access to any of the following?
Digital Volt Meter
Oscilloscope
JTAG debugger (I use the Amontec JTAG Key)
Regards,
Jason.

--- In l..., "dJsLiM" wrote:
>
> Hi everyone,
>
> I'm a complete newbie to LPC development. I got the Olimex LPC MT
2106
> board with a variable voltage powersupply from.
>
> I have set the power supply to 9V and plugged it into the board.
When
> I hook the power I see that the top line of the LCD display gets
> darker. No other indication of power seems visible.
>
> I'm using a normal DB9 serial cable to connect the board to my PC
on
> COM 1.
>
> I have located the jumper so that the two BSL pins are connected
> together. The two pins below the BSL do not have jumpers on them
as I
> removed it.
>
> I got the Philips 2000 flash utility then set it to LPC 2106. I
got a
> simple led.hex program online for trial.
>
> When I try to flah using "Upload to Flash" the utility it prompts
me
> to reset the board. So I hit the reset switch and then hit "ok".
>
> The utility then stalls for a bit and pops open an alert box
saying
> "Cannot communicate with test board!"
>
> Can anyone point me in the right direction?
>
> My apologies in advance if this question has been asked
previsouly. I
> tried doing a search but perhaps my choice of keywords is poor.
>
> thanks for your help!
>
> slim
>
----- Original Message -----
From: "Jason Morgan"
To:
Sent: Thursday, November 23, 2006 7:43 AM
Subject: [lpc2000] Re: problem communicating to LPC 2106 on Windows
> Hi,
>
> From looking at the schematic:
>
> The MT2106 board is intended for 9V AC operation, if you have used
> 9VDC it should still work.

I think the bridge rectifier is intended to allow operation from either
polarity input, not for AC operation. The smoothing will probably be
inadequate.

Leon

Leon Heller, G1HSM
Suzuki SV1000S motorcycle
l...@bulldoghome.com
http://webspace.webring.com/people/jl/leon_heller/
--- In l..., "dJsLiM" wrote:
>
...
>

Hi,
Here is a simple checklist:

1. Ensure that the signals are comming from PC to the MCU pins(check
cable, RS232 driver chip, soldering etc.);
2. Ensure that you pulldown the P0.14 of the MCU with BSL
jumper(check the voltage level on the MCU pin);
3. Ensure that the RESET button circuit is working properly(check the
voltage level on RESET pin with button pressed and relesed);
4. Be sure that you set the Philips Flash utility correctly;
5. Try to connect on different speeds;
6. ...
Leon,

I'm just going by what the datasheet for this module states at the
Olimex website - 6 to 9V AC or DC.

But just in case, let's check, time for a lunchbreak electronics
lesson.......

Let the CPU take about 60mA max. Let the LCD take 20mA. No idea if
this is right, but its probably a good guess.

Max input current is 80mA, its all linear regulators, so no power is
conserved. The peripherals run of a separate 12V supply.

A 9V supply is its RMS output value, we are interested in the peak
value. The 220uF cap has to hold the supply up from its peak value
of 9*srqt(2.0) = 12.7V. for a time until the supply reaches more
than the minimum input supply required for correct operation.

Its a bridge, so it doubles the mains freq (but the rise times are
the same), but the downside is we loose about 1.2V across it, in the
UK the mains is 50Hz (a worse case than 60Hz, used elsewhere)

So the main cap has to hold the supply up from a peak until the next
cycle is more than min internal supply voltage, which is 7V for the
5V regulator.

12.7-1.2.5 (remember those diodes)

Vo=Vin*sin(2*PI*f*t) (formula for a sine wave)

arcsin(Vo/Vin)/(2*PI*f)=t (re-arrange it as we are interested in t)

arcsin(7/11.5)/(2*PI*50)=2ms
add 5ms(1/4 of a 100 Hz cycle)=7ms

So, The 220uF cap must not have discharged to less than 7V in 7ms,
we assume the discharge current constant, so:

i=C*dv/dt

v=i*dt/C

v=(0.08*(7*10^-3))/(220*10^-6)=2.5V (remember, this is discharge)

We have lost 2.5V from 11.5V, and therefore the supply to 5V
regulator is never less than 9V, yippee!! Way in excess of what is
required.

Incidentaly, the 5V supply is not critical, as this only drives the
LCD, so the 3.3V and core voltage are safer, there is also other
capacitance elsewhere in the board, it all helps.

Conclusion: Olimex have got it right!!! Probably optimally - Or
have they? If you used 6VAC it might would not work, expecially if
you drive the CPU hard.

Also, almost all AC suplies are unregulated (think of the complexity
otherwise), so their low current RMS output voltages are way above
the stated output voltage, of course, this works in our favour.
I've measured 9Vac supplies at more than 12V before (off load).

Regards,
Jason.

--- In l..., "Leon Heller"
wrote:
>
> ----- Original Message -----
> From: "Jason Morgan"
> To:
> Sent: Thursday, November 23, 2006 7:43 AM
> Subject: [lpc2000] Re: problem communicating to LPC 2106 on Windows
> > Hi,
> >
> > From looking at the schematic:
> >
> > The MT2106 board is intended for 9V AC operation, if you have
used
> > 9VDC it should still work.
>
> I think the bridge rectifier is intended to allow operation from
either
> polarity input, not for AC operation. The smoothing will probably
be
> inadequate.
>
> Leon
>
> Leon Heller, G1HSM
> Suzuki SV1000S motorcycle
> leon.heller@...
> http://webspace.webring.com/people/jl/leon_heller/
>
Great!! Tutorial, Thanks Jason.
Warm Regards,
Mukund Deshmukh,
Beta Computronics Pvt Ltd,
10/1 IT Park, Parsodi,
Nagpur -10, India
Cell - +919422113746
----- Original Message -----
From: Jason Morgan
To: l...
Sent: Thursday, November 23, 2006 7:05 PM
Subject: [lpc2000] Re: problem communicating to LPC 2106 on Windows
Leon,

I'm just going by what the datasheet for this module states at the
Olimex website - 6 to 9V AC or DC.

But just in case, let's check, time for a lunchbreak electronics
lesson.......

Let the CPU take about 60mA max. Let the LCD take 20mA. No idea if
this is right, but its probably a good guess.

Max input current is 80mA, its all linear regulators, so no power is
conserved. The peripherals run of a separate 12V supply.

A 9V supply is its RMS output value, we are interested in the peak
value. The 220uF cap has to hold the supply up from its peak value
of 9*srqt(2.0) = 12.7V. for a time until the supply reaches more
than the minimum input supply required for correct operation.

Its a bridge, so it doubles the mains freq (but the rise times are
the same), but the downside is we loose about 1.2V across it, in the
UK the mains is 50Hz (a worse case than 60Hz, used elsewhere)

So the main cap has to hold the supply up from a peak until the next
cycle is more than min internal supply voltage, which is 7V for the
5V regulator.

12.7-1.2.5 (remember those diodes)

Vo=Vin*sin(2*PI*f*t) (formula for a sine wave)

arcsin(Vo/Vin)/(2*PI*f)=t (re-arrange it as we are interested in t)

arcsin(7/11.5)/(2*PI*50)=2ms
add 5ms(1/4 of a 100 Hz cycle)=7ms

So, The 220uF cap must not have discharged to less than 7V in 7ms,
we assume the discharge current constant, so:

i=C*dv/dt

v=i*dt/C

v=(0.08*(7*10^-3))/(220*10^-6)=2.5V (remember, this is discharge)

We have lost 2.5V from 11.5V, and therefore the supply to 5V
regulator is never less than 9V, yippee!! Way in excess of what is
required.

Incidentaly, the 5V supply is not critical, as this only drives the
LCD, so the 3.3V and core voltage are safer, there is also other
capacitance elsewhere in the board, it all helps.

Conclusion: Olimex have got it right!!! Probably optimally - Or
have they? If you used 6VAC it might would not work, expecially if
you drive the CPU hard.

Also, almost all AC suplies are unregulated (think of the complexity
otherwise), so their low current RMS output voltages are way above
the stated output voltage, of course, this works in our favour.
I've measured 9Vac supplies at more than 12V before (off load).

Regards,
Jason.

--- In l..., "Leon Heller"
wrote:
>
> ----- Original Message -----
> From: "Jason Morgan"
> To:
> Sent: Thursday, November 23, 2006 7:43 AM
> Subject: [lpc2000] Re: problem communicating to LPC 2106 on Windows
> > Hi,
> >
> > From looking at the schematic:
> >
> > The MT2106 board is intended for 9V AC operation, if you have
used
> > 9VDC it should still work.
>
> I think the bridge rectifier is intended to allow operation from
either
> polarity input, not for AC operation. The smoothing will probably
be
> inadequate.
>
> Leon
>
> Leon Heller, G1HSM
> Suzuki SV1000S motorcycle
> leon.heller@...
> http://webspace.webring.com/people/jl/leon_heller/
>