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eaydin
Joined: 25 May 2022
Posts: 10
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 Posted: Sun May 29, 2022 11:38 pm |
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| VCC 3.7V lion battery. I use 0.1uF capacitor on power stage. I try more capacitor in space assembly on circuit breadboard. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19568
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| Posted: Tue May 31, 2022 12:19 am |
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A nominal 3.7v Li-ion battery can be up to 4.2v when freshly charged.
Even at 3.7, it is above the rated maximum for an SD card. The SD card
spec has a rated voltage range of 2.7 to 3.6v (SD2 cards down to 1.8v). |
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asmallri
Joined: 12 Aug 2004
Posts: 1636
Location: Perth, Australia
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| Posted: Tue May 31, 2022 10:48 pm |
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Drop your SPI speed down to 5 MHz and retest. If that works successfully try increasing it to 10 MHz. It is rare to find a PIC implementation of an SD card using the SPI bus with an SPI speed above 10 MHz. At these speeds PCB layout becomes critical as is RF noise generation.
_________________
Regards, Andrew
http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!! |
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eaydin
Joined: 25 May 2022
Posts: 10
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| Posted: Wed Jun 01, 2022 12:24 am |
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| Ttelmah wrote: | A nominal 3.7v Li-ion battery can be up to 4.2v when freshly charged.
Even at 3.7, it is above the rated maximum for an SD card. The SD card
spec has a rated voltage range of 2.7 to 3.6v (SD2 cards down to 1.8v). |
Li-On bat has mid charge. Has a 3.5V
| asmallri wrote: | | Drop your SPI speed down to 5MHz and restest. If that works successfully try increeasing it to 10MHz. It is rare to find a PIC implementation of an SD card using the SPI bus with an SPI speed above 10MHz. At these speeds PCB layout becomes critical as is RF noise generation. |
How to run 5MHZ ? Thats what i know PIC run 4MHZ, 8MHZ, and PLL |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19568
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| Posted: Wed Jun 01, 2022 12:27 am |
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10M, is 'pushing it'. If you look at the timing diagrams, and add up the
minimum specified high time, low time, and the two rise and fall times,
you get 105nSec legal minimum. So 9.5MHz max. I like to use 8MHz
as the maximum that is generally reliable. |
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asmallri
Joined: 12 Aug 2004
Posts: 1636
Location: Perth, Australia
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| Posted: Wed Jun 01, 2022 5:10 am |
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| Ttelmah wrote: | | 10M, is 'pushing it'.... I like to use 8MHz as the maximum that is generally reliable. |
As do I :-)
_________________
Regards, Andrew
http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!! |
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