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ArduinoISP.ino does not properly handle word-based address for EEPROM read/write #2186

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#2188
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ArduinoISP.ino does not properly handle word-based address for EEPROM read/write#2186
#2188
@x0urc3

Description

@x0urc3
x0urc3
opened on Jun 14, 2022 · edited by x0urc3

Steps to reproduce
Reading and writing EEPROM using Adafruit ArduinoISP.ino will cause Bad EEPROM data. The official Arduino ArduinoISP.ino does not have similar issue. See avrdudes/avrdude/issues/990

Possible solution
The read and write EEPROM function does not handle word-based address. The high address byte is 0x00 in both function.

Adafruit_Learning_System_Guides/ArduinoISP/ArduinoISP/ArduinoISP.ino

Lines 550 to 557 in 0090edd

char eeprom_read_page(int length) {
// here again we have a word address
for (int x = 0; x < length; x++) {
byte ee = spi_transaction(0xA0, 0x00, _addr*2+x, 0xFF);
Serial.write( ee);
}
return STK_OK;
}

Adafruit_Learning_System_Guides/ArduinoISP/ArduinoISP/ArduinoISP.ino

Lines 487 to 496 in 0090edd

byte write_eeprom(int length) {
// here is a word address, so we use here*2
// this writes byte-by-byte,
// page writing may be faster (4 bytes at a time)
for (int x = 0; x < length; x++) {
spi_transaction(0xC0, 0x00, _addr*2+x, buff[x]);
delay(45);
}
return STK_OK;
}

Activity

TheKitty

TheKitty commented on Jun 14, 2022

@TheKitty
TheKitty
on Jun 14, 2022
Collaborator

Please submit a pull request if at all possible.

mcuee

mcuee commented on Jun 14, 2022

@mcuee
mcuee
on Jun 14, 2022 · edited by mcuee

FYI, Arduino's example has the fix back in Dec 2011.
arduino/arduino-examples@ea98fc8

Specific fix here.
rsbohn/ArduinoISP@bc480b0

x0urc3
linked a pull request that will close this issue on Jun 15, 2022
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        ArduinoISP.ino does not properly handle word-based address for EEPROM read/write · Issue #2186 · adafruit/Adafruit_Learning_System_Guides