Hi, Klaus Rudolph: > Hi again, > >> Example: >> SBI of bit 0 in PINB register should toggle (xor) PORTB.PB0. Using RMW >> approach, we read PINB = 0xff (because DDRB is input/tristate, read as >> '1' for each pin), we OR the bitmask (1<<0)=1 on top of it (=0xff) and >> write it back to PINB, *which toggles all PORTB bits* --> bug. > > PINB register is read only. What you want to achieve?
for many years already, AVR have a PIN toggle feature, for example ATmega644 datasheet says: > 12.2.2 Toggling the Pin > Writing a logic one to PINxn toggles the value of PORTxn, independent on the > value of DDRxn. > Note that the SBI instruction can be used to toggle one single bit in a port. This makes toggling a pin a 2 cycle/single instruction operation instead of IN/EOR/OUT. Simulavr in principle also supports this, although in a buggy way when using SBI instead of LDI/OUT. Just look at the implementation of HWPort in hwport.cpp. When I look through git-blame, the feature was introduced by Thomas K on 2009-12-04, commit 3f6a6882: > HWPort: new features PIN toggle PORT and variable port size > > This change adds also usage of HWPort in python interface (but usefull for > debugging only) and sets the right size and type of ports in ATtiny2313. Cheers, panic _______________________________________________ Simulavr-devel mailing list Simulavr-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/simulavr-devel
