August 10th, 2006
The Master Boot Record of my SD card starting at address 0×1BE (the important stuff). Bonus points to anyone who replies with comments stating what each byte of this block means.
Well, sorry that I haven’t posted lately, but I’ve been really quite busy. I’ve had quite a bit of success and the mp3 player project has gone through several key changes.
First, and most importantly, I’ve successfully (and reliably!) interfaced to the SD card. This took some work. On the breadboard pictured in one of the previous posts, I was getting some strange interference on the data line of the SD card. Because of this, I decided to switch to wire wrapping for my prototyping. It’s my first time wire wrapping so its still a bit sloppy, but is still leagues ahead of the breadboard in terms of expandability and neatness. After a few more headaches, I realized the problem; the first couple hundred bytes of my SD card are 0×00. I chose a more suitable address to read and it appeared to be working. After a few more tweaks it was reading consistantly and I was able to bump up the peak rate to around 305Kb/s.
Now I am on to the challenge of writing a FAT16 driver. Expect another post on details of this in a day or two.
Share and Enjoy:
These icons link to social bookmarking sites where readers can share and discover new web pages.
Posted in Mp3 Player | No Comments »
June 28th, 2006
MP3 Player Schematic
I decided to give a bit more details on my MP3 player today. Above is my original schematic that I designed back in January (I’ve really been lagging a bit on this project). The design remains basically the same today, with a few minor changes.
For instance, in the schematic I have the LCD backlight controlled through a transfer gate, but after looking at the PIC’s datasheet and measuring the current drawn by the backlight, I decided that I would be able to connect the LCD directly to the PIC. As an added bonus, I connected the LCD to one of the pulse width modulated pins on the PIC and now have fine control over the brightness of the backlight. This will allow me to fade the backlight on/off when the user hasn’t pressed any buttons in a certain time period (power saving feature, yay!).
On another front, the SD card still gives me problems, and I have sampled some 3.3V LM2936 voltage regulators from National Semiconductors1. I’m hoping that when the regulators arrive I will have more success with the SD card; imprecise voltages can have a large effect on the SD card operation from what I have read online. Up until now I have been powering my SD card through a simple voltage divider.
1.  A quick tip for those of you who want to order samples from National Semiconductor: make sure you don’t use your IEEE.org email alias. Due to the high number of samples requested from ieee.org email addresses, they want to charge you; instead use a low-brow email address like a university account and you should sail through without paying a dime.
Share and Enjoy:
These icons link to social bookmarking sites where readers can share and discover new web pages.
Posted in Mp3 Player | No Comments »
June 20th, 2006
Fireworks that we set off at my lake. My camera’s nightshot mode has a longer aperture time making these look really cool.
Well, it’s official; I am now an adult in the eyes of America (not that it really matters, I’ve been an adult in Canada for quite some time now).
To celebrate, a couple friends and myself went out to my lake with my parents. All in all, fun was had, although we got a bit wet when we decided to do a 5km hike through the rain on our way back to the city. But to be fair, we didn’t know it was going to rain when we started the hike.
Obligatory sunset photo
Read more for a couple more photos.
Read the rest of this entry »
Share and Enjoy:
These icons link to social bookmarking sites where readers can share and discover new web pages.
Posted in Uncategorized | 1 Comment »
