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by dwelch67
Sun May 27, 2012 2:05 pm
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

@dwelch67 Well done for getting it going, all those SD card insertions and removals are not fun. Very similar to the old days using the 8051 where it was a case of take the chip out of the socket, insert in ZIF socket of programmer, program, take out, put back into target board, test, oops, mistake...
by dwelch67
Sun May 27, 2012 1:54 pm
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

Please educate me/us on where I need to go or what I need to do to inform the right parties about errors in the datasheet.
by dwelch67
Sun May 27, 2012 6:36 am
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

I have a bootloader working now. http://github.com/dwelch67/raspberrypi/ You may find it ugly but it works. I didnt count the dozens/hundreds of sd card insertions it took to get to this point...no more! Hacking through the error(s) in the chip doc were quite painful.
by dwelch67
Sun May 27, 2012 4:23 am
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

That was quite painful. I figured it out though http://github.com/dwelch67/raspberrypi/uart01 This uses the mini uart, which is uart1 (TXD1, RXD1). Actually only TXD1, GPIO14. I dont understand all the fuss about making a MAX232 board, when there are at least three different flavors of ftdi boards a...
by dwelch67
Sun May 27, 2012 3:34 am
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

Does anyone have bare metal code that initializes the gpio/uart and transmits characters? This is driving me nuts...I can get the mini uart to spit something out, the other side isnt seeing it correctly (I have the proper level shifter on the host side). I can bit bang just fine. The full uart is no...
by dwelch67
Sat May 26, 2012 11:46 pm
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

typos in the manual it appears

page 12 ..5044 is the IER not IIR, next page 5048 is the IIR not IER, right?

in the IER description those should all be R/W bits.
by dwelch67
Sat May 26, 2012 11:34 pm
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

That was probably it. The docs say you should config the gpio first, that may have caused something on the rx, causing an interrupt. So I disabled the interrupts first, then disabled the uart, then was able to configure the gpio, and then configure and enable the uart. Not working yet, but over that...
by dwelch67
Sat May 26, 2012 10:34 pm
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

Yes, all bare metal.

Using physical addressing, replace 0x7Exxxxxx with 0x20xxxxxx, can blink leds and talk to timers and such, moving toward bringing up one of the uarts. Prefer the mini uart to the full uart, but am having problems with the mini.
by dwelch67
Sat May 26, 2012 10:01 pm
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

And getting hangs talking to the mini-uart. I write a 0x1 to the AUX_ENABLES then try to write to the control register in the mini uart and that appears to cause a hang. Am I missing something?
by dwelch67
Sat May 26, 2012 9:42 pm
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

I am struggling to turn off the pull down for GPIO14 and 15 (UART). from the diagram in the docs it implies that pull up/down are indpendent of function/alternate function. is that correct? If I have switched to the alternate function for the GPIO do I need to modify the pull up/down? What I am doin...
by dwelch67
Sat May 26, 2012 6:05 pm
Forum: Other programming languages
Topic: Programming the ARM chip
Replies: 134
Views: 42573

Re: Programming the ARM chip

Got my (first) raspberry pi yesterday http://github.com/dwelch67/raspberrypi I have just started a set of bare metal arm programming examples for the rpi. Quite disappointed that the arm jtag is not easier to get to. If nothing else a very small kernel.img that changes gpio pins to alternate functio...

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