Register Summary (Continued)AddressNameBit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0 $02 ($22) Reserved $01 ($21) Reserved $00 ($20) Reserved Notes: 1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses should never be written. 2. Some of the status flags are cleared by writing a logical one to them. Note that the CBI and SBI instructions will operate on all bits in the I/O register, writing a one back into any flag read as set, thus clearing the flag. The CBI and SBI instructions work with registers $00 to $1F only. 8AT90S/LS2333 and AT90S/LS4433 Document Outline Features Description Block Diagram Pin Descriptions VCC GND Port B (PB5..PB0) Port C (PC5..PC0) Port D (PD7..PD0) RESET XTAL1 XTAL2 AVCC AREF AGND Architectural Overview Register Summary (Continued) Instruction Set Summary (Continued) Ordering Information Pin Configurations