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updated readme

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David Welch
2012-05-27 11:09:10 -04:00
parent 507949cb1b
commit b04a3344d6
1 changed files with 28 additions and 3 deletions
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README
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@@ -22,9 +22,6 @@ And the schematic for the board
http://www.raspberrypi.org/wp-content/uploads/2012/04/Raspberry-Pi-Schematics-R1.0.pdf
(might be an old link, find the one on the wiki page)
Ultimately I will make a uart based bootloader. For now start with
blinker01
I dont normally use .data nor gcc libraries nor C libraries so you can
build most if not all of my examples using a gcc cross compilerl. Basically
it doesnt matter if you use arm-none-linux-gnueabi or arm-none-eabi.
@@ -34,4 +31,32 @@ easy to use but you can use it. Building your own toolchain from gnu
sources (binutils and gcc) is fairly straight forward and at some point
will create a script to do that for you.
My first bootloader is working, this will greatly save on wear and tear
on the sd card socket. You will need some sort of serial adapter.
The uart signals on the raspi are not at RS232 levels, you CANNOT
simply connect them to a "COM port", you will fry your raspberry pi.
A simple solution is to get these two items at sparkfun or something
similar (there are many ftdi usb to serial 3.3v solutions out there)
http://www.sparkfun.com/products/718
http://www.sparkfun.com/products/8430
On the raspberry pi, the connector with two rows of a bunch of pins is
P1. Starting at that corner of the board, the outside corner pin is
pin 2. From pin 2 heading toward the yellow rca connector the pins
are 2, 4, 6, 8, 10. Pin 6 connect to gnd on the usb to serial board
pin 8 is tx out of the raspi connect that to RX on the usb to serial
board. pin 10 is rx into the raspi, connect that to TX on the usb to
serial board. Careful not to have metal items on the usb to serial
board touch metal items on the raspberry pi (other than the three
connections described). On your host computer you will want to use
some sort of dumb terminal program, minicom, putty, etc. Set the
serial port (usb to serial board) to 115200 baud, 8 data bits, no
parity, 1 stop bit. NO flow control. With minicom you likely have
to save the config, exit minicom, then restart in order for flow control
changes to take effect.
going to work on a terminal based bootloder with xmodem, instead of the
proprietary solution in bootloader01.
I recommend you start with blinker01 and follow the discovery through
those to uart01, etc. Now that I have the bootloader working I have
to go back through these and generate a .hex file as well as a .img file.