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16  Using Arduino / Networking, Protocols, and Devices / Re: TC35 GSM module does not respond to "AT" command on: March 11, 2013, 06:01:05 am
I'm afraid that if you were directly connecting the RXD of the TC35i to the Arduino board, it might be damaged by now.
17  Using Arduino / Networking, Protocols, and Devices / Re: GPS Modules on: March 11, 2013, 05:58:54 am
Quote
Not all pins on the Leonardo support change interrupts, so only the following can be used for RX: 8, 9, 10, 11, 14 (MISO), 15 (SCK), 16 (MOSI).
18  Using Arduino / Networking, Protocols, and Devices / Re: TC35 GSM module does not respond to "AT" command on: March 10, 2013, 08:19:07 am
Another thing to try would be shorting the CTS & RTS together.
Some modem enabled these handshake on default setting based on my experience.
Worth a try I guess.

And are you sure 1 A is enough? Usually most module out there range from 1.8 - 2.5 A (Sierra, Cinterion, SIM, uBlox).
19  Using Arduino / Networking, Protocols, and Devices / Re: TC35 GSM module does not respond to "AT" command on: March 10, 2013, 07:11:19 am
I did read some thread over the net, some saying it the default baud rate is 19200 bps for this modem.
Not sure whether this is true, but worth trying out?
20  Using Arduino / Networking, Protocols, and Devices / Re: TC35 GSM module does not respond to "AT" command on: March 10, 2013, 06:02:15 am
Although the the checking of available character is perform after 5 s, there could be possibility that the character comes in after 5 s although it's rather unlikely. In that case, you serial check will return zero.
Why not doing something simpler like this:
Code:
if (Serial.available() > 0)
{
  gsmSerial.write(Serial.read());
}

if (gsmSerial.available() > 0)
{
  Serial.write(gsmSerial.read());
}

Whatever you type on the PC should be relayed to the modem and vice versa.
If this fails, it could be something simple like inadequate current of the power supply or a GND is not connected between the boards.
21  Using Arduino / Networking, Protocols, and Devices / Re: TC35 GSM module does not respond to "AT" command on: March 09, 2013, 12:18:17 pm
It could be wrong baud rate.

By the way, the line:
Code:
         
gsm_char = gsmSerial.read();
Serial.println(gsm_char); 
only read a single character.
22  Development / Other Hardware Development / Re: Diptrace Files for Shield Development on: February 20, 2013, 04:48:12 am
I think the pad hole size is a bit small (20 mil, 0.5 mm).
23  Using Arduino / Programming Questions / Re: PCF8563 Current Consumption on: December 03, 2012, 09:45:02 am
Hi Mark,

Quote
My intuition would be that something is leaving one of the I2C bus lines pulled low, which it shouldn't.
I just did some measurement on the data and clock lines. As the pull-up are being powered by a digital pin (vperiPin) on the Arduino, the measurement looks weird to me:

  • With the setAlarm function enabled, both SDA & SCL are around 25 mV and also 25 mV on the other end of the pull-up resistor (on vperiPin which is already being set as low. This is when the current measured is higher (few mA).
  • With the setAlarm function commented, both SDA & SCL are around 0.6 V and also 0.6V on the other end of the pull-up resistor (vperiPin is also set low in this case). This is when the current measured is low (uA range).
24  Using Arduino / Programming Questions / Re: PCF8563 Current Consumption on: December 03, 2012, 08:59:07 am
Hi Mark,

Yes, I'm putting the processor into sleep mode. It usually goes down to about 0.1 uA without the RTC.

I'm using a 4K7 pull-up for both data and clock.
It's weird because it only happens (higher consumption) when certain call function of the PCF8563 is being used like for example:

Code:
rtc.setAlarm(minute, 99, 99, 99);
digitalWrite(vperiPin, LOW);   
attachInterrupt(1, alarm, FALLING);

Then the MCU will be pushed to sleep soon after that. The vperiPin is used to power the I2C pull-up. So, I turn them off when not using them.
When I used functions like formatDate or formatTime, the current stays low.

If I were to comment out the setAlarm line, then the current goes low again. The current resulting from the attachInterrupt function is negligible. 
25  Using Arduino / Programming Questions / PCF8563 Current Consumption on: December 03, 2012, 07:39:05 am
Hi guys,

I'm using the library posted in the playground for PCF8563 RTC

As I'm using this for a low power application, I notice that whenever I use any function provided by the library that only performs write without requesting any data bytes from the RTC, the current consumption (the ATMega328P itself) would go up pretty high 3-4 mA and it stays there. For example, setAlarm and clearAlarm functions. The only differences I notice with these 2 function compared to the rest like formatDate and formatTime is the write and request for data sequence.

I think, there's something in the Wire and TWI library that is causing this although I'm not very sure.
Any guys came across this problem before?
26  Community / Products and Services / Re: Arduino Micro Debut in the US on: November 08, 2012, 12:41:10 am
Quote
FT230-XS SOIC package it's no smaller in size than the FT232R
It's like a 16-pin with 20-pin body! Caught that mistake in prototype before sending for production batch.
I'm not sure why you are not buying from E-14 Aussie? Free shipping but I guess out of stock at least until end of month.
27  Community / Products and Services / Re: Arduino Micro Debut in the US on: November 08, 2012, 12:22:39 am
Quote
but last time I looked the new ones were more expensive.
Bought FT231-XS few months back for USD1.56 at 250 pieces.
At single piece, it's pretty reasonable too. FT230-XS is few cent cheaper than that.
28  Community / Products and Services / Re: Arduino Micro Debut in the US on: November 08, 2012, 12:00:20 am
Quote
how reliable I've found FTDI chips to be in the past
The new FX series is cheaper too although now out of stock as they are fabbing the 2nd batch.
29  Community / Products and Services / Re: Arduino Micro Debut in the US on: November 07, 2012, 11:58:19 pm
One thing I don't like about 32U4 based board is the external interrupt pins (attachInterrupt) falls on what I need (D0-D3)!
And on D2 & D3, they are I2C pins.
30  Using Arduino / Networking, Protocols, and Devices / Re: Seeedstudio GPRS shield question on: October 25, 2012, 10:37:35 am
When you use the SIM on a phone, when you boot the phone up and if you need to key in the 4-pin thingy, then it's considered as locked.
The command AT+CPIN=? will let you know whether it's locked or not.
It's kinda scary if you wrongly write them in the firmware (after 3 times, it's locked).
For a GSM module which I wrote the library for (not SIM900), I omitted this SIM pin code function fearing someone might wrongly enter them for 3 times!
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