diff --git a/README b/README index b600afe..e8612b0 100644 --- a/README +++ b/README @@ -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.