SD Card pullup resistors, atmega 644 programmer, few questions
Posted: Mon Sep 24, 2018 5:31 am
I was following (e)uzebox project for few years and I finally managed to get all the required parts so now Im ready to start making my homebrew euzebox, and I have few questions (with more to come along building, for sure).
Just now soldering, and I have LC Technology SD card socket module with integrated 3.3V regulator, it has 10k ohm pull up resistors to 3.3V for MOSI, SCK and MISO lines (and the one for DATA1/DATA2 lines not used in this project). As they arent in schematics, do I need to remove them? Because it wont be possible to remove after soldering 8x2pin header connector to pcb, and if needed it can be easy added at later stage on main pcb. I saw few mentions of it (especially MISO pullup lately) in some discusion here on forum but without clear answer.
Picture and schematic of sd card module in question.
I dont have much experience with Atmel AVRs (was using PIC in past), except burning hex onto atmega8 long time ago with own-made simple LPT programmer and PonyProg. If needed, I'll made SI-Prog or STK200-compatible programmer. After some reading Im heading towards STK200, and planning to use 4Mhz crystal on programmer board, because im not sure that it will work for programming on 28.6363mhz crystal and i dont want to mess alot with bits and fuses to avoid possibile bricking avr644. Also im unsure, do I need to write bits before or after flashing Bootloader_0_4_5.hex? Im open for any other programmer/programming suggestions, but i dont need expensive programmers so try to avoid it.
I'm building enclosure for it (if wanted i'll post pictures when finished and hopefully working), using short (~5cm), thin (0.24mm) unshielded wires to connect SCART socket onto pcb (wires soldered at both ends). I hope that wont be a problem, and i wouldn't have signal issues because of that?
Just now soldering, and I have LC Technology SD card socket module with integrated 3.3V regulator, it has 10k ohm pull up resistors to 3.3V for MOSI, SCK and MISO lines (and the one for DATA1/DATA2 lines not used in this project). As they arent in schematics, do I need to remove them? Because it wont be possible to remove after soldering 8x2pin header connector to pcb, and if needed it can be easy added at later stage on main pcb. I saw few mentions of it (especially MISO pullup lately) in some discusion here on forum but without clear answer.
Picture and schematic of sd card module in question.
I dont have much experience with Atmel AVRs (was using PIC in past), except burning hex onto atmega8 long time ago with own-made simple LPT programmer and PonyProg. If needed, I'll made SI-Prog or STK200-compatible programmer. After some reading Im heading towards STK200, and planning to use 4Mhz crystal on programmer board, because im not sure that it will work for programming on 28.6363mhz crystal and i dont want to mess alot with bits and fuses to avoid possibile bricking avr644. Also im unsure, do I need to write bits before or after flashing Bootloader_0_4_5.hex? Im open for any other programmer/programming suggestions, but i dont need expensive programmers so try to avoid it.
I'm building enclosure for it (if wanted i'll post pictures when finished and hopefully working), using short (~5cm), thin (0.24mm) unshielded wires to connect SCART socket onto pcb (wires soldered at both ends). I hope that wont be a problem, and i wouldn't have signal issues because of that?