68HCS12

EE 308 Spring 2003 68HCS12 Address Space   68HCS12 has 16 address lines   68HCS12 can address ¡£¢¥¤ distinct locations   For 68HCS12, each location holds one byte (eight bits)   68HCS12 can address ¡£¢¥¤ bytes   ¡ ¢¦¤¨§ ©©   ¡¢¦¤ § ¡¤ ¡¢¦ § ©  !#"$¡ %§ ©& KB   ( !(' § ¡ ¢¦¨§ !#"¡ 0)   68HCS12 can address 64 KB www.DataSheet4U.com 1 EE 308 Spring 2003 68HCS12 Address Space " """ § "   Lowest address: """"""""""""""""¡  §  ¢¦¤ ¢ ¦ ¢ ¢£¢£¢ §  © &   Highest address: !!!!!!!!!!!!!!!!   § £ ¢¦¤ ¢¦ 0x0000 0 16 0xFFFF 65535 2 − 1 www.DataSheet4U.com 2 EE 308 Spring 2003 MEMORY TYPES RAM: ROM: PROM: EPROM: Random Access Memory (can read and write) Read Only Memory (programmed at factory) Programmable Read Only Memory (Program once at site) Erasable Programmable Read Only Memory (Program at site, can erase using UV light and reprogram) EEPROM: Electrically Erasable Programmable Read Only Memory (Program and erase using voltage rather than UV light) 68HCS12 has: 12 K RAM 4 KB EEPROM Can erase and reprogram any byte using normal 5V pow 256 KB Flash EEPROM Can erase using external 12V power supply www.DataSheet4U.com 3 EE 308 Spring 2003 68HCS12 Address Space 0x0000 Registers 0x03FF 0x0400 3 K Bytes EEPROM 0x0FFF 0x1000 User RAM 0x3BFF 0x3C00 0x3FFF 0x4000 0xFFFF 11 K 1 K Bytes D−Bug 12 RAM D−Bug 12 Flash EEPROM 1K www.DataSheet4U.com 4 EE 308 Spring 2003 68HCS12 ALU   Arithmetic Logic Unit (ALU) ...