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Ryan
O'Hara
- (8 posts)
Posted: 14 Sep 2010, 13:09
Microbuilder, for connection to an SD card are there any pullup resistors required for proper operation of the SD card or should everything be a direct connect?
Reply
Posted: 15 Sep 2010, 02:09
ohararp said:
Microbuilder, for connection to an SD card are there any pullup resistors required for proper operation of the SD card or should everything be a direct connect?
Normally, you simply need to connect the appropriates pins to the MCU and there shouldn't be a need for any pullups, though you'll want to add a largish decoupling cap to the VCC line on the SD card (47uF should be more than enough) since some cards draw more power than others.
-- Kevin (microbuilder.eu)
Posted: 16 Sep 2010, 11:09
ohararp said:
Microbuilder, for connection to an SD card are there any pullup resistors required for proper operation of the SD card or should everything be a direct connect?
Kevin, thanks for that. I am looking to port my SD gps datalogger design from the pic 18f parts to the 1343. SD connection and GPS parsing are at the top of the list.
Posted: 16 Sep 2010, 14:09
ohararp said:
Kevin, thanks for that. I am looking to port my SD gps datalogger design from the pic 18f parts to the 1343. SD connection and GPS parsing are at the top of the list.
Ryan:
There's already some code in the LPC1343 Code Base for SD cards (ChaN's FATFS, v0.07 I believe off the top of my head), which I can confirm works for SDHC cards as well. It was only recently added, but it's been working well for me, albeit SPI isn't the fastest method in the world to access or write large files. I'm sure it's fine for simple datalogging though. I haven't had a chance to update the documentation in a while, but if you look at sysinit.c you can see some test code that demonstrates the most common functionality.
Kevin.
Posted: 01 Jun 2012, 09:06
Kevin, any chance you have any file examples ther read/write to an sd card?