Serial port questions

[SimonLothar]

Cable is loose too.

Could you drop a photo like this, please?

This is a jack, which fits well. I am very curious, how the connectors of your cable look like.

[happy Profile]

Hope this helps..

[nsg Profile]

Happy,

as i wrote before I also have a problem connecting 2 casio calculators together.
Today, i figured out what i was doing wrong, same thing may be happening to you too.
I opened the case thinking to adjust springs (whatever that means) and it became immediately apparent that I do not insert connector all the way through.
I had to push it pretty hard before it went "click". The amount of force I had to apply was borderline disturbing and i was almost afraid to brek something.
After I applied similar procedure to the other calculator (I mean, inserting connector until it clicks), i had no problems establishing communication between them.

On a side note, it would really improve your close-up pictures if you learned how to use "macro" button.

[happy Profile]

I had to push it pretty hard before it went "click".
...
On a side note, it would really improve your close-up pictures if you learned how to use "macro" button.

NSG, You are a saviour! That was indeed the problem, thank you! I don't have a camera, used my phone to click the pic.

[Casimo Profile]

Maybe you have to press stronger.

[happy Profile]

Maybe you have to press stronger.

Thanks. The suggestion to look out for the 'click' did it though.

[gbl08ma Profile Website]

Yeah... I have noticed that usually you must apply a bit of pressure, on the 3-pin female port of Prizms which never had that port used, in order for the connector to be fully inserted. That extra bit of pressure usually goes unnecessary as you use the port more. I don't know if this is true for other Casio devices with 3-pin ports.

[happy Profile]

Transmit buffer:

1) I should check free space by calling Serial_GetFreeTransmitSpace() before calling Serial_BufferedTransmitNBytes(), right?

2) If I keep calling Serial_BufferedTransmitNBytes() and there is no cable attached, will the buffer get full at some point? When/how is this buffer cleared?

[SimonLothar]

1) I should check free space by calling Serial_GetFreeTransmitSpace() before calling Serial_BufferedTransmitNBytes(), right?

Serial_BufferedTransmitNBytes() returns 2 instead of 0, if there is not enough buffer space available. So it is not necessary to call Serial_GetFreeTransmitSpace() beforehand.

2) If I keep calling Serial_BufferedTransmitNBytes() and there is no cable attached, will the buffer get full at some point? When/how is this buffer cleared?

The serial transmit procedures are not aware of whether a cable is attached or not. Available data are sent interrupt driven until the transmit buffer is empty. Hence the buffer is cleared automatically.

[happy Profile]

Serial_BufferedTransmitNBytes() returns 2 instead of 0, if there is not enough buffer space available

Am I right in assuming that: 2 means that none of the data from bytes_to_transmit was written to the buffer?

If yes, don't I need to keep calling Serial_BufferedTransmitNBytes() with the same data until it returns 0? So, this can't be blocking, right? My program is in a main loop looking for user input. Whenever user enters something (say in a text box), I need to transfer it via serial, so I call Serial_BufferedTransmitNBytes(). But I can't build the retry logic here (keep calling the function till 0 is returned) because it would block the user. So I should have a queue in a timer and the main loop should write to the queue? And the function in the timer should take care of error codes, retries etc.?