Uploading skecth thrugh ISP while having GPS connected over Serial port [SOLVED]

Projects General Guidance
1

Hi there

Im building a GPS speedometer using a uBlox Neo6m (the one available here) an arduino pro mini and a HT16K33 mux chip.

I´m still in the debugging and prototyping phase. Already have most components more or less were they go in the enclosure.

However each time I have to upload the sketch, as we all know so far I have to unplug the GPS module from the HW serial port and plug the Serial to USB converter.

I plan to make a revision on my PCB to add the ISP pins to be able to update the sketch without need of unplugging anything.

Can this be done. Or to upload through ISP having the GPS connected (and possibly sending data) can interfere?

Why not use SWSerial to communicate with the GPS? I need 10Hz refresh rate, so baudrate is set to 115200 both arduino and GPS

Thanks

2

I think I've already tested this, and yes, you can upload using the ISP and activity on the serial pins makes no difference. The down side is you have no serial debug capability. Make sure the ISP programmer can support the supply current needed to power peripherals like a GPS, or whatever you have connected to, or on the board. Or supply separate power.

3

Fine - as long as you do not have anything else connected to the ISP pins. :astonished: Remember these are not unique, they connect to other I/O allocated pins. Just check which ones!

4

Hi,
Any reason you haven't tried putting the GPS on a Software Serial port?
Then you can program to the hardware ports freely?

Tom... :slight_smile:

5

TomGeorge:
Hi,
Any reason you haven't tried putting the GPS on a Software Serial port?
Then you can program to the hardware ports freely?

Tom... :slight_smile:

Hi Tom, yes the reason is that since Im using 10Hz refresh from the GPS I wanted to used 115200 baudrate

SW Serial AltSWSerial or NeoSwSerial all have its limitations in baudrate (38400) I think is the max you can get.

Since this speedo once the sketch is polished will not need anymore updating It´s a waste not to use in the end the HW serial for GPS connection

6

Paul__B:
Fine - as long as you do not have anything else connected to the ISP pins. :astonished: Remember these are not unique, they connect to other I/O allocated pins. Just check which ones!

Thanks, I think there wont be a problem Im only using the pro mini TX/RX and I2C ports, also I left pins D2,D3 and D4 to be triggers or configuration ports (like selecting speed in mph or kmh if D3 is high or low at the start of the sketch or selecting display brightness) Pins D11 D12 and D13 are not used.

THanks for the repply

7

aarg:
I think I've already tested this, and yes, you can upload using the ISP and activity on the serial pins makes no difference. The down side is you have no serial debug capability. Make sure the ISP programmer can support the supply current needed to power peripherals like a GPS, or whatever you have connected to, or on the board. Or supply separate power.

Thanks aarg.