We no longer sell products directly from the GHI Electronics website, click here for more details. Please find a Distributor to complete your online order. If you have any questions regarding this notice please contact us at support@ghielectronics.com.

F20 Developers' Guide

Last modified June 16, 2016

The F20 SoC is a low-cost yet full featured file system processor which communicates over UART with the host system and only needs 3.3V, GND, TX, and RX to operate.

The F20-uSD is a small off the shelf product exposing a micro-SD connector with the required interface pins.

The commands supported are a subset of the commands supported by the F40. Consult the below comparison and the File System User Manual to see which commands are supported and how to use them as well as for information on device startup.

The current version of the firmware is version 1.0.3 and can be found here.

Bootloader and Firmware Update

The F20 comes pre-programmed with a bootloader from GHI Electronics that allows you to easily update the firmware when updates are available. To enter the bootloader, hold LDR0 low on power up. For details on the bootloader, please see this document

Comparison

Feature F40 F20
Long File Name Yes Yes (max 247 character name and path)
Max Handles 16 (0 - F) 4 (0 - 3)
Max Access Speed ~1 MByte/s ~10 KByte/s
Access Interface SPI, I2C, UART UART
Media Interface 4-bit SD, USB SD over SPI
Power Consumption N/A 20 mA run, 0.1 mA standby
RTC Shared (internal) and backup (external 32,768 Hz) mode Shared (internal) only
Processor Crystal External 12 MHz crystal required Internal clock used
Controllable Startup UART Baud Rate Yes (firmware only) Yes

Commands

Command Description F40 F20
VGet VersionYesYes
#Enable EchoYesNo
ZDevice ControlYesYes (Z 0 and Z 3 only)
TInitialize Date/TimeYesYes (T S only)
SSet Date/TimeYesYes
GGet Date/TimeYesYes
BSet Baud RateYesYes
IInitialize MediaYesYes (I M:>2 only)
JGet StatusYesYes (J 0 only)
KGet Free SizeYesYes
@Initialize File and Folder ListYesYes
NGet Next FileYesYes
OOpen FileYesYes
RRead FileYesYes
WWrite FileYesYes
LWrite File Fast SPI ModeYesNo
FFlush FileYesYes
CClose FileYesYes
PFile SeekYesYes
YFile TellYesYes
DDelete FileYesYes
?Find FileYesYes
MCopy FileYesNo
ARename FileYesNo
ETest SpeedYesNo
QFormatYesYes
Leave feedback about this document.
Let us know if the information presented here was accurate, helpful and if you have any suggestions.
Leave feedback about this document.
Let us know if the information presented here was accurate, helpful and if you have any suggestions.

* Indicates required fields.
This form is only for feedback not support.
Review our how to find information guide on locating helpful resources.