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John0815
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| PIC18LF4550 - Mass Storage Device |
 Posted: Sun Jul 05, 2009 6:04 am |
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Hi everybody!
I'm a bit in trouble at the moment and I hope you can probably help me.
I've been using a PICLF4620 so far, but I changed it to a LF4550, as mentioned in the subject.
Problem #1: I use the old board and reconnected the pins of the SD card (SCL, SDA, SDO; CE remained the same) and the mini USB (D+/-, V_USB). Are there any additional resistors/capacitors necessary?!
Problem #2: I use the CCS C compiler and can use the old code except one line:
| Code: | | setup_adc(ADC_CLOCK_INTERNAL|ADC_TAD_MUL_0); |
This is because ADC_TAD_MUL_0 is not defined in the PIC18F4550.h header file. This code belongs to a sensor and is probably the reason why my system doesn't work anymore?! Or is it because of the schematics that have a mistake anywhere right now?
Problem #3: The main problem. I want to use the SD Card on the board via the USB as a Mass Storage Device on a PC. Data only gets written from the µC to the SD card and should only be read on the PC. I've read something of a firmware update and so on, but to be honest I don't know how this actually works?! I found a few files, but I'm not sure which is the right one AND all of them are not for CCS C?! Did anyone of you have a similar project with the 4550 and a SD card? Does anyone of you have a working firmware for CCS C? Maybe there's a tutorial anywhere?!
I hope you can help me because I'm a bit frustrated in between. Sorry for my stupid questions, but I'm not such a expert on that topic. Thanks a lot in advance! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Jul 05, 2009 3:30 pm |
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| Quote: |
I've been using a PICLF4620 so far, but I changed it to a LF4550.
Problem #1: I use the old board and reconnected the pins of the SD card
(SCL, SDA, SDO; CE remained the same) and the mini USB (D+/-,
V_USB). Are there any additional resistors/capacitors necessary?! |
On the 18F4550, pins C4 and C5 are dedicated to the USB. They don't
have any SPI functions available on them. The 18F4550 is not pin-
compatible with the 18F4620. You can't just drop it in as a replacement
chip in the same circuit.
| Quote: |
setup_adc(ADC_CLOCK_INTERNAL|ADC_TAD_MUL_0);
ADC_TAD_MUL_0 is not defined in the PIC18F4550.h header file.
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Then just delete that parameter from the setup_adc() statement.
Also, instead of using ADC_CLOCK_INTERNAL it's better if you use the
correct ADC divisor, based upon your PIC oscillator frequency. Look in
the ADC section of the PIC data sheet. They always have a table that
shows the correct divisor value for your oscillator frequency.
| Quote: |
I've read something of a firmware update and so on, but to be honest I
don't know how this actually works?! I found a few files, but I'm not sure
which is the right one AND all of them are not for CCS C?! |
Tell us where you are looking, when you see these files ?
Is it from the CCS USB developement package, which can be
downloaded from this page, if you have current maintenance ?
http://www.ccsinfo.com/compilerupdates.php
If so, some of the source files are for Windows applications and are
written in Delphi. |
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