Changing CS to Pin 14
ratbertDS opened this issue · comments
Hi for my project I have the CS Line wired to Pin 14 for the SD Card. I'm a bit of a newbie here to changing bootloaders. Can some one give me a clue to exactly what needs changing to make this work. The CPU is a 328p 3,3v Device.
Thanks!
By "Pin 14", do you mean the Arduino pin number (as you would use with digitalWrite(), etc.) or do you mean physical pin 14 on the ATmega328P chip?
If the latter, what is the IC package of your ATmega328P?
So I am using a 3,3v Pro Mini.
And I am connecting the SD Card as follows:
CS -> Arduino pin A0
MOSI -> Arduino D11
SCLK -> Arduino D13
MISO -> Arduino D12
Does that make any better sense? Sorry as I said newbie
OK. That's the information I needed. avr_boot doesn't use Arduino pin numbers to define the CS pin. It uses the PORT/BIT number. So the first thing is to determine the pin mapping of Arduino pin 14 on the Pro Mini. From this handy chart:
we can see that Arduino pin 14 is PC0 (PORTC, BIT 0).
You can define the CS pin port and bit either by editing lines 9-11 of the Makefile or via the SD_CS_PORT, SD_CS_DDR, and SD_CS_BIT arguments to make. I prefer the latter. So the correct make command is this:
make MCU_TARGET=atmega328p BOOT_ADR=0x7000 F_CPU=8000000 SD_CS_PORT=PORTC SD_CS_DDR=DDRC SD_CS_BIT=0 USE_LED=0 USE_UART=0 ADDED_CFLAGS="-Wextra -Wno-strict-aliasing" TARGET=$(MCU_TARGET)_cs14_$(F_CPU)L
Wow! Thank you so much..