Low byte rate when reading MMC
Posted: 25 Jul 2010 23:03
Hello,
I'm developing a mp3-player with a QVGA color screen using SD-card for mp3-file storage.
My problem is, that I can only read around 100kbytes/s which is not enough when I need to decode wav-files that has around 1400kbit/s or 180byte/s. How come it?
I have 6K2 pull-up's on every dataline (CS, CLK, DI, DO) and a 100nF capacitor on the supply as close to the card as possible. The socket for the microSD is a miniSD with soldered wires to it. They are approximatively 2,5cm long. All this is connected to the breadboard. My microcontroller is running @ 48MHz and the bus line is running fosc/4.
Shouldn't I be able to read at faster rates? Like 200-300 kbyte/s?
I also thought of shortening the wires to the socket because I had problems when they where longer, but I don't know if that is going to change any performance. What do u think is the problem?
Regards,
Simon H.A.
I'm developing a mp3-player with a QVGA color screen using SD-card for mp3-file storage.
My problem is, that I can only read around 100kbytes/s which is not enough when I need to decode wav-files that has around 1400kbit/s or 180byte/s. How come it?
I have 6K2 pull-up's on every dataline (CS, CLK, DI, DO) and a 100nF capacitor on the supply as close to the card as possible. The socket for the microSD is a miniSD with soldered wires to it. They are approximatively 2,5cm long. All this is connected to the breadboard. My microcontroller is running @ 48MHz and the bus line is running fosc/4.
Shouldn't I be able to read at faster rates? Like 200-300 kbyte/s?
I also thought of shortening the wires to the socket because I had problems when they where longer, but I don't know if that is going to change any performance. What do u think is the problem?
Regards,
Simon H.A.