Freescale 68HC12

Freescale 68HC12

The 68HC12 (6812 or HC12 for short) is a microcontroller family from Freescale Semiconductor with an 8-bit ALU and 16-bit linear addressing. Originally introduced in the mid 1990s, the architecture is an enhancement of the Freescale 68HC11. Programs written for the HC11 are usually compatible with the HC12, which has a few extra instructions. The first 68HC12 derivatives had a maximum bus speed of 8MHz and flash memory sizes up to 128 kB.

Contents

Architecture of the 68HC12

Like the 68HC11, the 68HC12 has 2 8-bit accumulators A and B (referred to as a single 16-bit accumulator, D, when A & B are cascaded so as to allow for operations involving 16 bits), 2 16-bit registers X and Y, a 16-bit program counter, a 16-bit stack pointer and an 8 bit Condition Code Register.

HCS12/MC9S12 derivatives

Beginning in 2000 the family was extended with the introduction of the MC9S12 derivatives which have bus speeds of up to 25 MHz and flash sizes up to 512 kB.

The MC9S12NE64 was introduced by Freescale in September 2004, claiming to be the "industry's first single-chip fast-Ethernet Flash microcontroller." It features a 25 MHz HCS12 CPU, 64 kB of FLASH EEPROM, 8 kB of RAM, and an Ethernet 10/100 Mbit/s controller.

MC9S12X derivatives

The MC9S12XDP512 which was introduced in 2004 has a bus speed of 40 MHz and a peripheral co-processor known as the XGATE which allows for some tasks to be offloaded from the CPU. The CPU of the S12X derivative also features several new instructions to increase performance.

Freescale announced the MC9S12XEP100 in May 2006 to further extend the S12X family to 50MHz bus speed and add a Memory protection unit (based on segmentation) and a hardware scheme to provide Emulated EEPROM. HCS12 products contain a single processor, the HCS12X feature the additional XGATE peripheral processor.

The XGATE co-processor is a 16-bit RISC processor operating at twice the main bus clock. It offloads work from the HC12 core by handling interrupts only and does not run a background loop. The first versions of the XGATE do not allow for higher priority interrupts to pre-empt a currently handled interrupt, but the "XGATEV3" as featured in the 9S12XEP100 does allow this. The HC12 can trigger software interrupts on the XGATE core. A semaphore system is implemented to allow the S12X and XGATE cores to share peripherals.

External links

but HCS12X contains XGATE peripheral processor


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • Freescale 68HC11 — Motorola MC68HC11, plastic DIP. The MC68HC11A8 is available …   Wikipedia

  • Freescale 68HC08 — Les Freescale 68HC08 sont des microcontrôleurs de la gamme 8 bits fabriqués par Freescale[1] (précédemment Motorola) sur base du cœur CPU08[2], dérivé du dérivé du CPU du Motorola 6800. Ils ont été conçus comme les successeurs améliorés des… …   Wikipédia en Français

  • Freescale 683XX — The Freescale 683xx (formerly Motorola 683xx) is a family of compatible microcontrollers that use a Freescale 68000 based CPU core. The family was designed using a Hardware Description Language, making the parts synthesizable, and amenable to… …   Wikipedia

  • List of Freescale products — The following is a partial list of Freescale Semiconductor products, including products formerly manufactured by Motorola until 2004.MicroprocessorsEarly microprocessors*Motorola MC14500B Industrial Control Unit (ICU) (1 bit) *Motorola 6800 (8… …   Wikipedia

  • Liste der Freescale-Produkte — Dies ist eine nicht ganz vollständige Liste der Freescale Semiconductor (ehemals Motorola) bis etwa 2004. Inhaltsverzeichnis 1 Mikroprozessoren 1.1 Frühe Mikroprozessoren 1.2 68000 Serie (CISC) …   Deutsch Wikipedia

  • Motorola 6800 —      Motorola MC6800   >> Центральный процессор …   Википедия

  • 16-bit — This article is about 16 bit in computer architecture. For the color encoding, see Highcolor. For the era of computer gaming commonly referred to as 16 bit, see History of video game consoles (fourth generation) Processors 1 bit 4 bit 8 bit 12… …   Wikipedia

  • Motorola 6800 family — The 6800 family of 8 bit microprocessors (µPs) and microcontrollers (µCs) is based upon the Motorola 6800 CPU. The architecture also inspired the MOS Technology 6502, and that company initially started business producing 6800 clones. The chips… …   Wikipedia

  • Accumulator (computing) — In a computer s central processing unit (CPU), an accumulator is a register in which intermediate arithmetic and logic results are stored. Without a register like an accumulator, it would be necessary to write the result of each calculation… …   Wikipedia

  • Micro controleur — Microcontrôleur Le Motorola 68HC11, ici en boîtier PLCC, est un microcontrôleur réputé. Un microcontrôleur est un circuit intégré qui rassemble les éléments essentiels d un ordinateur : processeur, mémoires (mémoire morte pour le programme,… …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”