LPCXpresso IDE中的主题 Re: gps read data lpc1769

gps read data lpc1769

lpcware — Thu, 16 Jun 2016 01:20:24 GMT

Content originally posted in LPCWare by dragilla on Fri Nov 18 04:01:03 MST 2011
Hello,

I have a gps receiver that prints out serial data at 20hz.
Is there a way I can save data from it without engaging the processor?
What I mean is that I have a main process (loop) working at constant frequency (thanks to a timer). The frequency of that loop is 5 times bigger than the frequency of the gps. I can't wait in my loop for the data to come.
So I thought that maybe there is some built-in mechanism that would get the data for me and save it somewhere (a register or buffer) so I can read it in my loop. Let me know if it's possible.

edit: there are two lines in the manual that I found interesting (Chapter 14: LPC17xx UART0/2/3, Features):
- 16 byte Receive and Transmit FIFOs.
- Supports DMA for both transmit and receive.

Is this what I'm looking for?

cheers,
--
Luke

Re: gps read data lpc1769

lpcware — Thu, 16 Jun 2016 01:20:25 GMT

Content originally posted in LPCWare by Ex-Zero on Fri Nov 18 04:20:01 MST 2011
UART Buffer :confused:

Re: gps read data lpc1769

lpcware — Thu, 16 Jun 2016 01:20:26 GMT

Content originally posted in LPCWare by dragilla on Fri Nov 18 04:22:44 MST 2011
Well, zero, I don't know what my lpcxpresso i capable of, yet. I know what I want to do and I'm asking if this is possible and if so, by what means.

edit: So (as I read you here: http://knowledgebase.nxp.com/showthread.php?t=1723) there is now way to buffer my data usnig dma? I must create a UART ISR and there fill up my own buffer?

Re: gps read data lpc1769

lpcware — Thu, 16 Jun 2016 01:20:26 GMT

Content originally posted in LPCWare by Polux rsv on Fri Nov 18 06:04:56 MST 2011
GPS will send strings longer than the UART buffer size. You have to use software buffer, feeded by chars received through the interrupt. Your main loop will periodicaly check if CR/LF was received from GPS. If yes, it will empty the buffer and decode the values received. Some GPS parsers are available on internet.

For your project, I suggest you use a RTOS. I have FreeRtos handling the GPS task, the sensors+IMU task, the can task and the terminal/telemetry task. It will handle all the message passing stuf between the tasks.

Angelo

Re: gps read data lpc1769

lpcware — Thu, 16 Jun 2016 01:20:27 GMT

Content originally posted in LPCWare by dragilla on Fri Nov 18 06:15:20 MST 2011
I will read about rtos. Thanks.
ps: did you find your power commander code?