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Topic: Possible communication solutions - TM1628 Keypad module (in DVD Players, etc) (Read 201 times) previous topic - next topic

pbala

Hi, I am a newbie to this site. Can anyone else tell me if there are other communication solutions ?

To Communicate with TM1628 (through SDIO bidirectionally) - I have used the following successfully -
             1. Using GPIO pins on the arduino.
             2. Using GPIO pins (through port manipulation, faster).
             3. SPI Interface & f/32 clock frequency (at around 375kHz)

Other communication solutions i have been unsuccessful with -
             1. i2C
             2. Rs232

Are there any other methods of communicating with TM1628 (scan keys as well as display LED data.. bidirectionally) or the above methods need to be retried in a different way ?

pylon

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Are there any other methods of communicating with TM1628 (scan keys as well as display LED data.. bidirectionally) or the above methods need to be retried in a different way ?
Is this just an academic question? You have a fast way to access the chip (SPI), you have a flexible way (GPIO), what else do you need? BTW, this is not bad as I haven't found a non-Chinese datasheet for this chip.

pbala

Thanks for your reply. Definitely not an academic question.
Since the chip has only three wires, (CLK, STB and SDIO), i am finding it difficult to read and write to the chip through SPI, GPIO is fairly slow, even by using direct PORT manipulation.
Was wondering if i could use a fairly standard reliable way to do this.

pylon

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i am finding it difficult to read and write to the chip through SPI
With an appropriate circuit it's pretty standard SPI. How did you connect it to the Arduino?

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Was wondering if i could use a fairly standard reliable way to do this.
The reliable way to do this is using GPIOs. If that's too slow for you, please specify what speed you need.

pbala

Through SPI, exactly what kind of circuitry is required ? If you mean adding a schott key diode or a resistor, it is better to change the direction of the MOSI or MISO (depending on Master or Slave) so that it does not interfere.
I connected it directly MOSI & MISO(shorted both), while reading or writing i changed the direction of ports, so no intereference.
With an appropriate circuit it's pretty standard SPI. How did you connect it to the Arduino?

The reliable way to do this is using GPIOs. If that's too slow for you, please specify what speed you need.
I am going to try this, i am sure in my code i made some mistake. I will update once i am successful.
Thanks for your support pylon.

pylon

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I connected it directly MOSI & MISO(shorted both), while reading or writing i changed the direction of ports, so no intereference.
You cannot change the directions of the pins while in SPI mode. You should connect the MOSI pin through a 10k resistor. Then you can use the SPI interface as usual, just ensure you're writing 0x00 bytes while receiving.

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